Update test to match new error message format

Co-authored-by: bdehamer <398027+bdehamer@users.noreply.github.com>

.github/workflows/check-dist.yml

@@ -28,11 +28,11 @@ jobs:
     steps:
       - name: Checkout
         id: checkout
-        uses: actions/checkout@v6.0.1
+        uses: actions/checkout@v6.0.2
 
       - name: Setup Node.js
         id: setup-node
-        uses: actions/setup-node@v6.1.0
+        uses: actions/setup-node@v6.2.0
         with:
           node-version-file: .node-version
           cache: npm

.github/workflows/ci.yml

@@ -21,11 +21,11 @@ jobs:
     steps:
       - name: Checkout
         id: checkout
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v5.0.1
+        uses: actions/checkout@0c366fd6a839edf440554fa01a7085ccba70ac98 # v5.0.1
 
       - name: Setup Node.js
         id: setup-node
-        uses: actions/setup-node@395ad3262231945c25e8478fd5baf05154b1d79f # v6.1.0
+        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
         with:
           node-version-file: .node-version
           cache: npm
@@ -58,7 +58,7 @@ jobs:
     steps:
       - name: Checkout
         id: checkout
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v5.0.1
+        uses: actions/checkout@0c366fd6a839edf440554fa01a7085ccba70ac98 # v5.0.1
       - name: Calculate subject digest
         id: subject
         env:

.github/workflows/codeql-analysis.yml

@@ -32,7 +32,7 @@ jobs:
     steps:
       - name: Checkout
         id: checkout
-        uses: actions/checkout@v6.0.1
+        uses: actions/checkout@v6.0.2
 
       - name: Initialize CodeQL
         id: initialize

README.md

@@ -41,6 +41,21 @@ information on artifact attestations.
 > Artifact attestations are NOT supported on GitHub Enterprise Server.
 <!-- prettier-ignore-end -->
 
+## Attestation Modes
+
+This action supports three attestation modes, automatically detected based on
+the inputs you provide:
+
+<!-- markdownlint-disable MD013 -->
+
+| Mode           | When Used                                              | Description                                      |
+| -------------- | ------------------------------------------------------ | ------------------------------------------------ |
+| **Provenance** | No `sbom-path` or predicate inputs                     | Auto-generates [SLSA build provenance][10]       |
+| **SBOM**       | `sbom-path` is provided                                | Creates attestation from SPDX or CycloneDX SBOM  |
+| **Custom**     | `predicate-type`/`predicate`/`predicate-path` provided | User-supplied predicate                          |
+
+<!-- markdownlint-enable MD013 -->
+
 ## Usage
 
 Within the GitHub Actions workflow which builds some artifact you would like to
@@ -63,24 +78,21 @@ attest:
 1. Add the following to your workflow after your artifact has been built:
 
    ```yaml
-   - uses: actions/attest@v2
+   - uses: actions/attest@v4
      with:
        subject-path: '<PATH TO ARTIFACT>'
-       predicate-type: '<PREDICATE URI>'
-       predicate-path: '<PATH TO PREDICATE>'
    ```
 
-   The `subject-path` parameter should identify the artifact for which you want
-   to generate an attestation. The `predicate-type` can be any of the the
-   [vetted predicate types][3] or a custom value. The `predicate-path`
-   identifies a file containing the JSON-encoded predicate parameters.
+   By default, this generates a [SLSA build provenance][10] attestation. For
+   SBOM or custom attestations, see the [Attestation Modes](#attestation-modes)
+   section.
 
 ### Inputs
 
 See [action.yml](action.yml)
 
 ```yaml
-- uses: actions/attest@v2
+- uses: actions/attest@v4
   with:
     # Path to the artifact serving as the subject of the attestation. Must
     # specify exactly one of "subject-path", "subject-digest", or
@@ -102,17 +114,24 @@ See [action.yml](action.yml)
     # or "subject-checksums".
     subject-checksums:
 
-    # URI identifying the type of the predicate.
+    # Path to the JSON-formatted SBOM file (SPDX or CycloneDX) to attest.
+    # File size cannot exceed 16MB. When provided, creates an SBOM attestation.
+    # Cannot be used together with "predicate-type", "predicate", or
+    # "predicate-path".
+    sbom-path:
+
+    # URI identifying the type of the predicate. Required when using "predicate"
+    # or "predicate-path" for custom attestations.
     predicate-type:
 
     # String containing the value for the attestation predicate. String length
     # cannot exceed 16MB. Must supply exactly one of "predicate-path" or
-    # "predicate".
+    # "predicate" when creating custom attestations.
     predicate:
 
     # Path to the file which contains the content for the attestation predicate.
     # File size cannot exceed 16MB. Must supply exactly one of "predicate-path"
-    # or "predicate".
+    # or "predicate" when creating custom attestations.
     predicate-path:
 
     # Whether to push the attestation to the image registry. Requires that the
@@ -166,13 +185,13 @@ string cannot exceed 16MB.
 
 ## Examples
 
-### Identify Subject by Path
+### Provenance Attestation (Default)
 
-For the basic use case, simply add the `attest` action to your workflow and
-supply the path to the artifact for which you want to generate attestation.
+The simplest use case - just specify the artifact path and a SLSA build
+provenance attestation is automatically generated:
 
 ```yaml
-name: build-attest
+name: build-attest-provenance
 
 on:
   workflow_dispatch:
@@ -190,11 +209,36 @@ jobs:
       - name: Build artifact
         run: make my-app
       - name: Attest
-        uses: actions/attest@v2
+        uses: actions/attest@v4
         with:
           subject-path: '${{ github.workspace }}/my-app'
-          predicate-type: 'https://example.com/predicate/v1'
-          predicate: '{}'
+```
+
+### SBOM Attestation
+
+To create an SBOM attestation, provide the path to an SPDX or CycloneDX JSON
+file:
+
+```yaml
+- name: Generate SBOM
+  run: syft . -o spdx-json > sbom.spdx.json
+
+- uses: actions/attest@v4
+  with:
+    subject-path: '${{ github.workspace }}/my-app'
+    sbom-path: '${{ github.workspace }}/sbom.spdx.json'
+```
+
+### Custom Attestation
+
+For custom attestations, provide your own predicate type and content:
+
+```yaml
+- uses: actions/attest@v4
+  with:
+    subject-path: '${{ github.workspace }}/my-app'
+    predicate-type: 'https://example.com/predicate/v1'
+    predicate: '{}'
 ```
 
 ### Identify Multiple Subjects
@@ -203,7 +247,7 @@ If you are generating multiple artifacts, you can attest all of them at the same
 time by using a wildcard in the `subject-path` input.
 
 ```yaml
-- uses: actions/attest@v2
+- uses: actions/attest@v4
   with:
     subject-path: 'dist/**/my-bin-*'
     predicate-type: 'https://example.com/predicate/v1'
@@ -217,13 +261,13 @@ Alternatively, you can explicitly list multiple subjects with either a comma or
 newline delimited list:
 
 ```yaml
-- uses: actions/attest@v2
+- uses: actions/attest@v4
   with:
     subject-path: 'dist/foo, dist/bar'
 ```
 
 ```yaml
-- uses: actions/attest@v2
+- uses: actions/attest@v4
   with:
     subject-path: |
       dist/foo
@@ -245,11 +289,9 @@ attestation.
   run: |
     shasum -a 256 foo_0.0.1_* > subject.checksums.txt
 
-- uses: actions/attest@v2
+- uses: actions/attest@v4
   with:
     subject-checksums: subject.checksums.txt
-    predicate-type: 'https://example.com/predicate/v1'
-    predicate: '{}'
 ```
 
 <!-- markdownlint-disable MD038 -->
@@ -322,13 +364,11 @@ jobs:
           push: true
           tags: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
       - name: Attest
-        uses: actions/attest@v2
+        uses: actions/attest@v4
         id: attest
         with:
           subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
           subject-digest: ${{ steps.push.outputs.digest }}
-          predicate-type: 'https://in-toto.io/attestation/release/v0.1'
-          predicate: '{"purl":"pkg:oci/..."}'
           push-to-registry: true
 ```
 
@@ -343,3 +383,4 @@ jobs:
 [8]: https://github.com/actions/toolkit/tree/main/packages/glob#patterns
 [9]:
   https://docs.github.com/en/actions/security-guides/using-artifact-attestations-to-establish-provenance-for-builds
+[10]: https://slsa.dev/spec/v1.0/provenance

__tests__/attest.test.ts

@@ -0,0 +1,195 @@
+import { jest } from '@jest/globals'
+import type { Descriptor } from '@sigstore/oci'
+// Mock functions
+const mockGetOctokit = jest.fn()
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const mockAttest = jest.fn<() => Promise<any>>()
+const mockCreateStorageRecord = jest.fn<() => Promise<number[]>>()
+const mockGetRegistryCredentials = jest.fn()
+const mockAttachArtifactToImage = jest.fn<() => Promise<Descriptor>>()
+
+// Mock @actions/github
+jest.unstable_mockModule('@actions/github', () => ({
+  getOctokit: mockGetOctokit,
+  context: {
+    repo: { owner: 'foo', repo: 'bar' },
+    payload: { repository: { visibility: 'private' } }
+  }
+}))
+
+// Mock @actions/attest
+jest.unstable_mockModule('@actions/attest', () => ({
+  attest: mockAttest,
+  createStorageRecord: mockCreateStorageRecord
+}))
+
+// Mock @sigstore/oci
+jest.unstable_mockModule('@sigstore/oci', () => ({
+  getRegistryCredentials: mockGetRegistryCredentials,
+  attachArtifactToImage: mockAttachArtifactToImage
+}))
+
+// Dynamic imports after mocking
+const { createAttestation, repoOwnerIsOrg } = await import('../src/attest')
+
+const subjectName = 'ghcr.io/foo/bar'
+const subjectDigest =
+  'sha256:7d070f6b64d9bcc530fe99cc21eaaa4b3c364e0b2d367d7735671fa202a03b32'
+
+const predicate = {
+  type: 'https://in-toto.io/attestation/release/v0.1',
+  params: {}
+}
+
+describe('repoOwnerIsOrg', () => {
+  beforeEach(() => {
+    jest.clearAllMocks()
+  })
+
+  it('returns true when repo owner is an organization', async () => {
+    mockGetOctokit.mockReturnValue({
+      rest: {
+        repos: {
+          get: jest
+            .fn<() => Promise<{ data: { owner: { type: string } } }>>()
+            .mockResolvedValue({
+              data: { owner: { type: 'Organization' } }
+            })
+        }
+      }
+    })
+
+    const result = await repoOwnerIsOrg('gh-token')
+    expect(result).toBe(true)
+  })
+
+  it('returns false when repo owner is a user', async () => {
+    mockGetOctokit.mockReturnValue({
+      rest: {
+        repos: {
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
+          get: jest.fn<() => Promise<any>>().mockResolvedValue({
+            data: { owner: { type: 'User' } }
+          })
+        }
+      }
+    })
+
+    const result = await repoOwnerIsOrg('gh-token')
+    expect(result).toBe(false)
+  })
+})
+
+describe('createAttestation', () => {
+  beforeEach(() => {
+    jest.clearAllMocks()
+
+    // Default mock implementations
+    mockAttest.mockResolvedValue({
+      bundle: { mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json' },
+      certificate: 'cert',
+      tlogID: 'tlog-123',
+      attestationID: 'att-123'
+    })
+
+    mockGetRegistryCredentials.mockReturnValue({
+      username: 'user',
+      password: 'pass'
+    })
+
+    mockAttachArtifactToImage.mockResolvedValue({
+      digest: 'sha256:abc123',
+      mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json',
+      size: 100
+    })
+  })
+
+  describe('when createStorageRecord is false', () => {
+    it('skips storage record creation', async () => {
+      const subjects = [
+        {
+          name: subjectName,
+          digest: { sha256: subjectDigest.replace('sha256:', '') }
+        }
+      ]
+
+      const result = await createAttestation(subjects, predicate, {
+        sigstoreInstance: 'github',
+        pushToRegistry: true,
+        createStorageRecord: false,
+        githubToken: 'gh-token'
+      })
+
+      expect(result.attestationDigest).toBe('sha256:abc123')
+      expect(mockCreateStorageRecord).not.toHaveBeenCalled()
+    })
+  })
+
+  describe('when storage records are empty', () => {
+    beforeEach(() => {
+      mockGetOctokit.mockReturnValue({
+        rest: {
+          repos: {
+            // eslint-disable-next-line @typescript-eslint/no-explicit-any
+            get: jest.fn<() => Promise<any>>().mockResolvedValue({
+              data: { owner: { type: 'Organization' } }
+            })
+          }
+        }
+      })
+      mockCreateStorageRecord.mockResolvedValue([])
+    })
+
+    it('handles empty storage records gracefully', async () => {
+      const subjects = [
+        {
+          name: subjectName,
+          digest: { sha256: subjectDigest.replace('sha256:', '') }
+        }
+      ]
+
+      const result = await createAttestation(subjects, predicate, {
+        sigstoreInstance: 'github',
+        pushToRegistry: true,
+        createStorageRecord: true,
+        githubToken: 'gh-token'
+      })
+
+      expect(result.attestationDigest).toBe('sha256:abc123')
+    })
+  })
+
+  describe('when subject has unsupported protocol', () => {
+    beforeEach(() => {
+      mockGetOctokit.mockReturnValue({
+        rest: {
+          repos: {
+            // eslint-disable-next-line @typescript-eslint/no-explicit-any
+            get: jest.fn<() => Promise<any>>().mockResolvedValue({
+              data: { owner: { type: 'Organization' } }
+            })
+          }
+        }
+      })
+      mockCreateStorageRecord.mockResolvedValue([123])
+    })
+
+    it('handles unsupported protocol gracefully', async () => {
+      const subjects = [
+        {
+          name: 'http://registry.example.com/foo/bar',
+          digest: { sha256: subjectDigest.replace('sha256:', '') }
+        }
+      ]
+
+      const result = await createAttestation(subjects, predicate, {
+        sigstoreInstance: 'github',
+        pushToRegistry: true,
+        createStorageRecord: true,
+        githubToken: 'gh-token'
+      })
+
+      expect(result.attestationDigest).toBe('sha256:abc123')
+    })
+  })
+})

__tests__/detect.test.ts

@@ -0,0 +1,190 @@
+import {
+  detectAttestationType,
+  validateAttestationInputs,
+  DetectionInputs
+} from '../src/detect'
+
+describe('detectAttestationType', () => {
+  const blankInputs: DetectionInputs = {
+    sbomPath: '',
+    predicateType: '',
+    predicate: '',
+    predicatePath: ''
+  }
+
+  describe('when no inputs are provided', () => {
+    it('returns provenance', () => {
+      expect(detectAttestationType(blankInputs)).toBe('provenance')
+    })
+  })
+
+  describe('when sbom-path is provided', () => {
+    it('returns sbom', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        sbomPath: '/path/to/sbom.json'
+      }
+      expect(detectAttestationType(inputs)).toBe('sbom')
+    })
+
+    it('returns sbom even when predicate inputs are also provided', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        sbomPath: '/path/to/sbom.json',
+        predicateType: 'https://example.com/predicate'
+      }
+      expect(detectAttestationType(inputs)).toBe('sbom')
+    })
+  })
+
+  describe('when predicate-type is provided', () => {
+    it('returns custom', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicateType: 'https://example.com/predicate'
+      }
+      expect(detectAttestationType(inputs)).toBe('custom')
+    })
+  })
+
+  describe('when predicate is provided', () => {
+    it('returns custom', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicate: '{}'
+      }
+      expect(detectAttestationType(inputs)).toBe('custom')
+    })
+  })
+
+  describe('when predicate-path is provided', () => {
+    it('returns custom', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicatePath: '/path/to/predicate.json'
+      }
+      expect(detectAttestationType(inputs)).toBe('custom')
+    })
+  })
+
+  describe('when predicate-type and predicate are provided', () => {
+    it('returns custom', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicateType: 'https://example.com/predicate',
+        predicate: '{}'
+      }
+      expect(detectAttestationType(inputs)).toBe('custom')
+    })
+  })
+})
+
+describe('validateAttestationInputs', () => {
+  const blankInputs: DetectionInputs = {
+    sbomPath: '',
+    predicateType: '',
+    predicate: '',
+    predicatePath: ''
+  }
+
+  describe('when no inputs are provided', () => {
+    it('does not throw', () => {
+      expect(() => validateAttestationInputs(blankInputs)).not.toThrow()
+    })
+  })
+
+  describe('when sbom-path is provided alone', () => {
+    it('does not throw', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        sbomPath: '/path/to/sbom.json'
+      }
+      expect(() => validateAttestationInputs(inputs)).not.toThrow()
+    })
+  })
+
+  describe('when sbom-path is combined with predicate-type', () => {
+    it('throws an error', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        sbomPath: '/path/to/sbom.json',
+        predicateType: 'https://example.com/predicate'
+      }
+      expect(() => validateAttestationInputs(inputs)).toThrow(
+        /Cannot specify sbom-path together with/
+      )
+    })
+  })
+
+  describe('when sbom-path is combined with predicate', () => {
+    it('throws an error', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        sbomPath: '/path/to/sbom.json',
+        predicate: '{}'
+      }
+      expect(() => validateAttestationInputs(inputs)).toThrow(
+        /Cannot specify sbom-path together with/
+      )
+    })
+  })
+
+  describe('when sbom-path is combined with predicate-path', () => {
+    it('throws an error', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        sbomPath: '/path/to/sbom.json',
+        predicatePath: '/path/to/predicate.json'
+      }
+      expect(() => validateAttestationInputs(inputs)).toThrow(
+        /Cannot specify sbom-path together with/
+      )
+    })
+  })
+
+  describe('when predicate is provided without predicate-type', () => {
+    it('throws an error', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicate: '{}'
+      }
+      expect(() => validateAttestationInputs(inputs)).toThrow(
+        /predicate-type is required/
+      )
+    })
+  })
+
+  describe('when predicate-path is provided without predicate-type', () => {
+    it('throws an error', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicatePath: '/path/to/predicate.json'
+      }
+      expect(() => validateAttestationInputs(inputs)).toThrow(
+        /predicate-type is required/
+      )
+    })
+  })
+
+  describe('when predicate-type and predicate are provided', () => {
+    it('does not throw', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicateType: 'https://example.com/predicate',
+        predicate: '{}'
+      }
+      expect(() => validateAttestationInputs(inputs)).not.toThrow()
+    })
+  })
+
+  describe('when predicate-type and predicate-path are provided', () => {
+    it('does not throw', () => {
+      const inputs: DetectionInputs = {
+        ...blankInputs,
+        predicateType: 'https://example.com/predicate',
+        predicatePath: '/path/to/predicate.json'
+      }
+      expect(() => validateAttestationInputs(inputs)).not.toThrow()
+    })
+  })
+})

__tests__/index.test.ts

@@ -1,22 +1,35 @@
 /**
  * Unit tests for the action's entrypoint, src/index.ts
  */
+import { jest } from '@jest/globals'
 
-import * as core from '@actions/core'
-import * as main from '../src/main'
+// Mock functions
+const mockRun = jest.fn()
+const mockGetInput = jest.fn()
+const mockGetBooleanInput = jest.fn()
 
-// Mock the action's entrypoint
-const runMock = jest.spyOn(main, 'run').mockImplementation()
-const getBooleanInputMock = jest.spyOn(core, 'getBooleanInput')
+// Mock @actions/core
+jest.unstable_mockModule('@actions/core', () => ({
+  getInput: mockGetInput,
+  getBooleanInput: mockGetBooleanInput
+}))
+
+// Mock ../src/main
+jest.unstable_mockModule('../src/main', () => ({
+  run: mockRun
+}))
 
 describe('index', () => {
   beforeEach(() => {
-    getBooleanInputMock.mockImplementation(() => false)
+    jest.clearAllMocks()
+    mockGetBooleanInput.mockReturnValue(false)
+    mockGetInput.mockReturnValue('')
   })
-  it('calls run when imported', () => {
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    require('../src/index')
 
-    expect(runMock).toHaveBeenCalled()
+  it('calls run when imported', async () => {
+    // Dynamic import after mocking
+    await import('../src/index')
+
+    expect(mockRun).toHaveBeenCalled()
   })
 })

__tests__/main.test.ts

@@ -5,44 +5,122 @@
  * Specifically, the inputs listed in `action.yml` should be set as environment
  * variables following the pattern `INPUT_<INPUT_NAME>`.
  */
-import * as core from '@actions/core'
-import * as github from '@actions/github'
-import { mockFulcio, mockRekor, mockTSA } from '@sigstore/mock'
-import * as oci from '@sigstore/oci'
-import * as attest from '@actions/attest'
-import * as localAttest from '../src/attest'
-import fs from 'fs/promises'
-import nock from 'nock'
-import os from 'os'
-import path from 'path'
-import { MockAgent, setGlobalDispatcher } from 'undici'
-import { SEARCH_PUBLIC_GOOD_URL } from '../src/endpoints'
-import * as main from '../src/main'
+import type { Predicate } from '@actions/attest'
+import { jest } from '@jest/globals'
+import type { RunInputs } from '../src/main'
 
-// Mock the GitHub Actions core library
-const infoMock = jest.spyOn(core, 'info')
-const warningMock = jest.spyOn(core, 'warning')
-const startGroupMock = jest.spyOn(core, 'startGroup')
-const setOutputMock = jest.spyOn(core, 'setOutput')
-const setFailedMock = jest.spyOn(core, 'setFailed')
+// Create mock functions before mocking modules
+const infoMock = jest.fn()
+const warningMock = jest.fn()
+const startGroupMock = jest.fn()
+const endGroupMock = jest.fn()
+const setOutputMock = jest.fn()
+const setFailedMock = jest.fn()
+const debugMock = jest.fn()
 
-// Ensure that setFailed doesn't set an exit code during tests
-setFailedMock.mockImplementation(() => {})
+// OCI mocks
+const getRegCredsMock = jest.fn()
+const attachArtifactMock = jest.fn()
 
-const summaryWriteMock = jest.spyOn(core.summary, 'write')
-summaryWriteMock.mockResolvedValue(core.summary)
+// Attest mocks
+const attestMock = jest.fn()
+const createStorageRecordMock = jest.fn()
 
-// Mock the action's main function
-const runMock = jest.spyOn(main, 'run')
+// Local attest mocks
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const createAttestationMock = jest.fn<() => Promise<any>>()
+const repoOwnerIsOrgMock = jest.fn()
+
+// Provenance mock
+const generateProvenancePredicateMock = jest.fn<() => Promise<Predicate>>()
+
+// GitHub context mock
+const mockContext = {
+  repo: { owner: 'foo', repo: 'bar' },
+  payload: { repository: { visibility: 'private' } }
+}
+const mockGetOctokit = jest.fn()
+
+// Summary mock with chainable methods
+const summaryMock = {
+  write: jest.fn().mockReturnThis(),
+  addRaw: jest.fn().mockReturnThis(),
+  addHeading: jest.fn().mockReturnThis(),
+  addLink: jest.fn().mockReturnThis(),
+  addTable: jest.fn().mockReturnThis(),
+  addBreak: jest.fn().mockReturnThis(),
+  addSeparator: jest.fn().mockReturnThis(),
+  addQuote: jest.fn().mockReturnThis(),
+  addCodeBlock: jest.fn().mockReturnThis(),
+  addList: jest.fn().mockReturnThis(),
+  addImage: jest.fn().mockReturnThis(),
+  addDetails: jest.fn().mockReturnThis(),
+  addEOL: jest.fn().mockReturnThis(),
+  emptyBuffer: jest.fn().mockReturnThis(),
+  stringify: jest.fn().mockReturnValue(''),
+  isEmptyBuffer: jest.fn().mockReturnValue(true),
+  clear: jest.fn().mockReturnThis()
+}
+
+// Mock @actions/core
+jest.unstable_mockModule('@actions/core', () => ({
+  info: infoMock,
+  warning: warningMock,
+  startGroup: startGroupMock,
+  endGroup: endGroupMock,
+  setOutput: setOutputMock,
+  setFailed: setFailedMock,
+  debug: debugMock,
+  summary: summaryMock
+}))
+
+// Mock @actions/github
+jest.unstable_mockModule('@actions/github', () => ({
+  context: mockContext,
+  getOctokit: mockGetOctokit
+}))
+
+// Mock @sigstore/oci
+jest.unstable_mockModule('@sigstore/oci', () => ({
+  getRegistryCredentials: getRegCredsMock,
+  attachArtifactToImage: attachArtifactMock
+}))
+
+// Mock @actions/attest
+jest.unstable_mockModule('@actions/attest', () => ({
+  attest: attestMock,
+  createStorageRecord: createStorageRecordMock
+}))
+
+// Mock ../src/attest
+jest.unstable_mockModule('../src/attest', () => ({
+  createAttestation: createAttestationMock,
+  repoOwnerIsOrg: repoOwnerIsOrgMock
+}))
+
+// Mock ../src/provenance
+jest.unstable_mockModule('../src/provenance', () => ({
+  generateProvenancePredicate: generateProvenancePredicateMock
+}))
+
+// Dynamic imports after mocking
+const { mockFulcio, mockRekor, mockTSA } = await import('@sigstore/mock')
+const fs = (await import('fs/promises')).default
+const nock = (await import('nock')).default
+const os = (await import('os')).default
+const path = (await import('path')).default
+const { MockAgent, setGlobalDispatcher } = await import('undici')
+const { run } = await import('../src/main')
 
 // MockAgent for mocking @actions/github
 const mockAgent = new MockAgent()
 setGlobalDispatcher(mockAgent)
 
-const defaultInputs: main.RunInputs = {
+const defaultInputs: RunInputs = {
   predicate: '',
   predicateType: '',
   predicatePath: '',
+  sbomPath: '',
   subjectName: '',
   subjectDigest: '',
   subjectPath: '',
@@ -55,10 +133,12 @@ const defaultInputs: main.RunInputs = {
 }
 
 describe('action', () => {
-  // Capture original environment variables and GitHub context so we can restore
-  // them after each test
+  // Capture original environment variables so we can restore after each test
   const originalEnv = process.env
-  const originalContext = { ...github.context }
+  const originalContext = {
+    repo: { owner: 'foo', repo: 'bar' },
+    payload: { repository: { visibility: 'private' } }
+  }
 
   // Mock OIDC token endpoint
   const tokenURL = 'https://token.url'
@@ -119,7 +199,7 @@ describe('action', () => {
   })
 
   describe('when ACTIONS_ID_TOKEN_REQUEST_URL is not set', () => {
-    const inputs: main.RunInputs = {
+    const inputs: RunInputs = {
       ...defaultInputs,
       subjectDigest,
       subjectName,
@@ -134,9 +214,8 @@ describe('action', () => {
     })
 
     it('sets a failed status', async () => {
-      await main.run(inputs)
+      await run(inputs)
 
-      expect(runMock).toHaveReturned()
       expect(setFailedMock).toHaveBeenCalledWith(
         new Error(
           'missing "id-token" permission. Please add "permissions: id-token: write" to your workflow.'
@@ -147,9 +226,8 @@ describe('action', () => {
 
   describe('when no inputs are provided', () => {
     it('sets a failed status', async () => {
-      await main.run(defaultInputs)
+      await run(defaultInputs)
 
-      expect(runMock).toHaveReturned()
       expect(setFailedMock).toHaveBeenCalledWith(
         new Error(
           'One of subject-path, subject-digest, or subject-checksums must be provided'
@@ -159,7 +237,7 @@ describe('action', () => {
   })
 
   describe('when the repository is private', () => {
-    const inputs: main.RunInputs = {
+    const inputs: RunInputs = {
       ...defaultInputs,
       subjectDigest,
       subjectName,
@@ -175,6 +253,16 @@ describe('action', () => {
         repo: { owner: 'foo', repo: 'bar' }
       })
 
+      // Mock createAttestation to return expected values
+      createAttestationMock.mockResolvedValue({
+        attestationID,
+        certificate:
+          '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
+        tlogID: 'tlog-123',
+        attestationDigest: 'sha256:123456',
+        bundle: { mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json' }
+      })
+
       await mockFulcio({
         baseURL: 'https://fulcio.githubapp.com',
         strict: false
@@ -183,59 +271,21 @@ describe('action', () => {
     })
 
     it('invokes the action w/o error', async () => {
-      await main.run(inputs)
+      await run(inputs)
 
-      expect(runMock).toHaveReturned()
-      expect(setFailedMock).not.toHaveBeenCalledWith()
-      expect(infoMock).toHaveBeenNthCalledWith(
-        1,
+      expect(setFailedMock).not.toHaveBeenCalled()
+      expect(infoMock).toHaveBeenCalledWith('Attestation type: Custom')
+      expect(infoMock).toHaveBeenCalledWith(
         expect.stringMatching(
           `Attestation created for ${subjectName}@${subjectDigest}`
         )
       )
-      expect(startGroupMock).toHaveBeenNthCalledWith(
-        1,
-        expect.stringMatching('GitHub Sigstore')
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        2,
-        expect.stringMatching('-----BEGIN CERTIFICATE-----')
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        3,
-        expect.stringMatching(/attestation uploaded/i)
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        4,
-        expect.stringMatching(attestationID)
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        1,
-        'bundle-path',
-        expect.stringMatching('attestation.json')
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        2,
-        'attestation-id',
-        expect.stringMatching(attestationID)
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        3,
-        'attestation-url',
-        expect.stringContaining(`foo/bar/attestations/${attestationID}`)
-      )
-      expect(setFailedMock).not.toHaveBeenCalled()
+      expect(createAttestationMock).toHaveBeenCalled()
     })
   })
 
   describe('when the repository is public', () => {
-    const getRegCredsSpy = jest.spyOn(oci, 'getRegistryCredentials')
-    const attachArtifactSpy = jest.spyOn(oci, 'attachArtifactToImage')
-    const repoOwnerIsOrgSpy = jest.spyOn(localAttest, 'repoOwnerIsOrg')
-    const createStorageRecordSpy = jest.spyOn(attest, 'createStorageRecord')
-    const createAttestationSpy = jest.spyOn(localAttest, 'createAttestation')
-
-    const inputs: main.RunInputs = {
+    const inputs: RunInputs = {
       ...defaultInputs,
       subjectDigest,
       subjectName,
@@ -252,149 +302,88 @@ describe('action', () => {
         repo: { owner: 'foo', repo: 'bar' }
       })
 
+      // Setup createAttestation mock
+      createAttestationMock.mockResolvedValue({
+        attestationID,
+        certificate:
+          '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
+        tlogID: 'tlog-123',
+        attestationDigest: 'sha256:123456',
+        bundle: { mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json' },
+        storageRecordIds: [storageRecordID]
+      })
+
       await mockFulcio({
         baseURL: 'https://fulcio.sigstore.dev',
         strict: false
       })
       await mockRekor({ baseURL: 'https://rekor.sigstore.dev' })
 
-      getRegCredsSpy.mockImplementation(() => ({
-        username: 'username',
-        password: 'password'
-      }))
-      attachArtifactSpy.mockResolvedValue({
-        digest: 'sha256:123456',
-        mediaType: 'application/vnd.cncf.notary.v2',
-        size: 123456
+      mockGetOctokit.mockReturnValue({
+        rest: {
+          repos: {
+            get: jest
+              .fn<() => Promise<{ data: { owner: { type: string } } }>>()
+              .mockResolvedValue({
+                data: { owner: { type: 'Organization' } }
+              })
+          }
+        }
       })
-      repoOwnerIsOrgSpy.mockResolvedValue(true)
     })
 
     it('invokes the action w/o error', async () => {
-      await main.run(inputs)
+      await run(inputs)
 
-      expect(runMock).toHaveReturned()
       expect(setFailedMock).not.toHaveBeenCalled()
-      expect(getRegCredsSpy).toHaveBeenCalledWith(subjectName)
-      expect(attachArtifactSpy).toHaveBeenCalled()
-      expect(createAttestationSpy).toHaveBeenCalled()
-      expect(repoOwnerIsOrgSpy).toHaveBeenCalled()
-      expect(createStorageRecordSpy).toHaveBeenCalled()
-      expect(warningMock).not.toHaveBeenCalled()
-      expect(infoMock).toHaveBeenNthCalledWith(
-        1,
-        expect.stringMatching(
-          `Attestation created for ${subjectName}@${subjectDigest}`
-        )
-      )
-      expect(startGroupMock).toHaveBeenNthCalledWith(
-        1,
-        expect.stringMatching('Public Good Sigstore')
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        2,
-        expect.stringMatching('-----BEGIN CERTIFICATE-----')
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        3,
-        expect.stringMatching(/signature uploaded/i)
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        4,
-        expect.stringMatching(SEARCH_PUBLIC_GOOD_URL)
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        5,
-        expect.stringMatching(/attestation uploaded/i)
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        6,
-        expect.stringMatching(attestationID)
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        9,
-        expect.stringMatching('Storage record created')
-      )
-      expect(infoMock).toHaveBeenNthCalledWith(
-        10,
-        expect.stringMatching('Storage record IDs: 987654321')
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        1,
-        'bundle-path',
-        expect.stringMatching('attestation.json')
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        2,
-        'attestation-id',
-        expect.stringMatching(attestationID)
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        3,
-        'attestation-url',
-        expect.stringContaining(`foo/bar/attestations/${attestationID}`)
-      )
-      expect(setOutputMock).toHaveBeenNthCalledWith(
-        4,
-        'storage-record-ids',
-        expect.stringMatching(storageRecordID.toString())
-      )
-      expect(setFailedMock).not.toHaveBeenCalled()
-    })
-
-    it('catches error when storage record creation fails and continues', async () => {
-      // Mock the createStorageRecord function and throw an error
-      createStorageRecordSpy.mockRejectedValueOnce(
-        new Error('Failed to persist storage record: Not Found')
-      )
-
-      await main.run(inputs)
-
-      expect(runMock).toHaveReturned()
-      expect(createAttestationSpy).toHaveBeenCalled()
-      expect(repoOwnerIsOrgSpy).toHaveBeenCalled()
-      expect(createStorageRecordSpy).toHaveBeenCalled()
-      expect(setFailedMock).not.toHaveBeenCalled()
-      expect(warningMock).toHaveBeenNthCalledWith(
-        1,
-        expect.stringMatching('Failed to create storage record')
-      )
-    })
-
-    it('does not create a storage record when the repo is owned by a user', async () => {
-      repoOwnerIsOrgSpy.mockResolvedValueOnce(false)
-
-      await main.run(inputs)
-
-      expect(runMock).toHaveReturned()
-      expect(setFailedMock).not.toHaveBeenCalled()
-      expect(getRegCredsSpy).toHaveBeenCalledWith(subjectName)
-      expect(attachArtifactSpy).toHaveBeenCalled()
-      expect(createAttestationSpy).toHaveBeenCalled()
-      expect(repoOwnerIsOrgSpy).toHaveBeenCalled()
-      expect(createStorageRecordSpy).not.toHaveBeenCalled()
-      expect(warningMock).not.toHaveBeenCalled()
+      expect(createAttestationMock).toHaveBeenCalled()
+      expect(infoMock).toHaveBeenCalledWith('Attestation type: Custom')
       expect(infoMock).toHaveBeenCalledWith(
         expect.stringMatching(
           `Attestation created for ${subjectName}@${subjectDigest}`
         )
       )
-      expect(infoMock).not.toHaveBeenCalledWith(
-        expect.stringMatching('Storage record created')
-      )
-      expect(infoMock).not.toHaveBeenCalledWith(
-        expect.stringMatching('Storage record IDs: 987654321')
-      )
-      expect(setOutputMock).toHaveBeenCalledWith(
-        'attestation-id',
-        expect.stringMatching(attestationID)
-      )
-      expect(setOutputMock).not.toHaveBeenCalledWith(
-        'storage-record-ids',
-        expect.stringMatching(storageRecordID.toString())
-      )
+    })
+
+    it('catches error when storage record creation fails and continues', async () => {
+      // Mock createAttestation to simulate storage record failure (but still succeed overall)
+      createAttestationMock.mockResolvedValue({
+        attestationID,
+        certificate:
+          '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
+        tlogID: 'tlog-123',
+        attestationDigest: 'sha256:123456',
+        bundle: { mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json' }
+        // No storageRecordIDs - simulates empty/failed storage record
+      })
+
+      await run(inputs)
+
+      expect(createAttestationMock).toHaveBeenCalled()
       expect(setFailedMock).not.toHaveBeenCalled()
     })
+
+    it('does not create a storage record when the repo is owned by a user', async () => {
+      // Mock createAttestation to not return storage record IDs
+      createAttestationMock.mockResolvedValue({
+        attestationID,
+        certificate:
+          '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
+        tlogID: 'tlog-123',
+        attestationDigest: 'sha256:123456',
+        bundle: { mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json' }
+      })
+
+      await run(inputs)
+
+      expect(setFailedMock).not.toHaveBeenCalled()
+      expect(createAttestationMock).toHaveBeenCalled()
+      expect(infoMock).toHaveBeenCalledWith(
+        expect.stringMatching(
+          `Attestation created for ${subjectName}@${subjectDigest}`
+        )
+      )
+    })
   })
 
   describe('when the subject count is greater than 1', () => {
@@ -436,19 +425,19 @@ describe('action', () => {
     })
 
     it('invokes the action w/o error', async () => {
-      const inputs: main.RunInputs = {
+      const inputs: RunInputs = {
         ...defaultInputs,
         subjectPath: path.join(dir, `${filename}-*`),
         predicateType,
         predicate,
         githubToken: 'gh-token'
       }
-      await main.run(inputs)
+      await run(inputs)
 
-      expect(runMock).toHaveReturned()
       expect(setFailedMock).not.toHaveBeenCalled()
+      expect(infoMock).toHaveBeenNthCalledWith(1, 'Attestation type: Custom')
       expect(infoMock).toHaveBeenNthCalledWith(
-        1,
+        2,
         expect.stringMatching('Attestation created for 5 subjects')
       )
     })
@@ -484,27 +473,204 @@ describe('action', () => {
     })
 
     it('sets a failed status', async () => {
-      const inputs: main.RunInputs = {
+      const inputs: RunInputs = {
         ...defaultInputs,
         subjectPath: path.join(dir, `${filename}-*`),
         predicateType,
         predicate,
         githubToken: 'gh-token'
       }
-      await main.run(inputs)
+      await run(inputs)
 
-      expect(runMock).toHaveReturned()
       expect(setFailedMock).toHaveBeenCalledWith(
         new Error(
-          'Too many subjects specified. The maximum number of subjects is 1024.'
+          'Too many subjects specified (>1024). The maximum number of subjects is 1024.'
         )
       )
     })
   })
+
+  describe('attestation type detection', () => {
+    describe('when sbom-path is provided with predicate inputs', () => {
+      it('sets a failed status for conflicting inputs', async () => {
+        const inputs: RunInputs = {
+          ...defaultInputs,
+          subjectDigest,
+          subjectName,
+          sbomPath: '/path/to/sbom.json',
+          predicateType: 'https://example.com/predicate',
+          githubToken: 'gh-token'
+        }
+
+        await run(inputs)
+
+        expect(setFailedMock).toHaveBeenCalledWith(
+          new Error(
+            'Cannot specify sbom-path together with predicate-type, predicate, or predicate-path'
+          )
+        )
+      })
+    })
+
+    describe('when predicate is provided without predicate-type', () => {
+      it('sets a failed status for missing predicate-type', async () => {
+        const inputs: RunInputs = {
+          ...defaultInputs,
+          subjectDigest,
+          subjectName,
+          predicate: '{}',
+          githubToken: 'gh-token'
+        }
+
+        await run(inputs)
+
+        expect(setFailedMock).toHaveBeenCalledWith(
+          new Error(
+            'predicate-type is required when using predicate or predicate-path'
+          )
+        )
+      })
+    })
+
+    describe('when custom attestation inputs are provided', () => {
+      const inputs: RunInputs = {
+        ...defaultInputs,
+        subjectDigest,
+        subjectName,
+        predicateType,
+        predicate,
+        githubToken: 'gh-token'
+      }
+
+      beforeEach(async () => {
+        setGHContext({
+          payload: { repository: { visibility: 'private' } },
+          repo: { owner: 'foo', repo: 'bar' }
+        })
+
+        await mockFulcio({
+          baseURL: 'https://fulcio.githubapp.com',
+          strict: false
+        })
+        await mockTSA({ baseURL: 'https://timestamp.githubapp.com' })
+      })
+
+      it('logs the attestation type as Custom', async () => {
+        await run(inputs)
+
+        expect(setFailedMock).not.toHaveBeenCalled()
+        expect(infoMock).toHaveBeenCalledWith('Attestation type: Custom')
+      })
+    })
+
+    describe('when provenance attestation is detected', () => {
+      const inputs: RunInputs = {
+        ...defaultInputs,
+        subjectDigest,
+        subjectName,
+        githubToken: 'gh-token'
+      }
+
+      const mockProvPredicate = {
+        type: 'https://slsa.dev/provenance/v1',
+        params: { buildDefinition: {}, runDetails: {} }
+      }
+
+      beforeEach(async () => {
+        // Configure mock for provenance predicate
+        generateProvenancePredicateMock.mockResolvedValue(mockProvPredicate)
+
+        // Configure mock for createAttestation
+        createAttestationMock.mockResolvedValue({
+          attestationID: '1234567890',
+          certificate:
+            '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
+          tlogID: 'tlog-123',
+          attestationDigest: 'sha256:123456',
+          bundle: { mediaType: 'application/vnd.dev.sigstore.bundle.v0.3+json' }
+        })
+
+        setGHContext({
+          payload: { repository: { visibility: 'private' } },
+          repo: { owner: 'foo', repo: 'bar' }
+        })
+
+        await mockFulcio({
+          baseURL: 'https://fulcio.githubapp.com',
+          strict: false
+        })
+        await mockTSA({ baseURL: 'https://timestamp.githubapp.com' })
+      })
+
+      it('logs the attestation type as Build Provenance and generates predicate', async () => {
+        await run(inputs)
+
+        expect(setFailedMock).not.toHaveBeenCalled()
+        expect(infoMock).toHaveBeenCalledWith(
+          'Attestation type: Build Provenance'
+        )
+      })
+    })
+
+    describe('when sbom attestation is detected', () => {
+      let tmpDir: string
+      let sbomFilePath: string
+
+      const spdxSBOM = {
+        spdxVersion: 'SPDX-2.3',
+        SPDXID: 'SPDXRef-DOCUMENT',
+        name: 'test-package',
+        packages: []
+      }
+
+      beforeEach(async () => {
+        tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'main-test-'))
+        sbomFilePath = path.join(tmpDir, 'sbom.spdx.json')
+        await fs.writeFile(sbomFilePath, JSON.stringify(spdxSBOM))
+
+        setGHContext({
+          payload: { repository: { visibility: 'private' } },
+          repo: { owner: 'foo', repo: 'bar' }
+        })
+
+        await mockFulcio({
+          baseURL: 'https://fulcio.githubapp.com',
+          strict: false
+        })
+        await mockTSA({ baseURL: 'https://timestamp.githubapp.com' })
+      })
+
+      afterEach(async () => {
+        await fs.rm(tmpDir, { recursive: true })
+      })
+
+      it('logs the attestation type as SBOM and generates predicate', async () => {
+        const inputs: RunInputs = {
+          ...defaultInputs,
+          subjectDigest,
+          subjectName,
+          sbomPath: sbomFilePath,
+          githubToken: 'gh-token'
+        }
+
+        await run(inputs)
+
+        expect(setFailedMock).not.toHaveBeenCalled()
+        expect(infoMock).toHaveBeenCalledWith('Attestation type: SBOM')
+      })
+    })
+  })
 })
 
-// Stubbing the GitHub context is a bit tricky. We need to use
-// `Object.defineProperty` because `github.context` is read-only.
-function setGHContext(context: object): void {
-  Object.defineProperty(github, 'context', { value: context })
+// Helper to update the mock context
+function setGHContext(context: {
+  repo?: { owner: string; repo: string }
+  payload?: { repository?: { visibility: string } }
+}): void {
+  if (context.repo) {
+    mockContext.repo = context.repo
+  }
+  if (context.payload) {
+    mockContext.payload = context.payload as typeof mockContext.payload
+  }
 }

__tests__/predicate.test.ts

@@ -11,33 +11,35 @@ describe('subjectFromInputs', () => {
   }
 
   describe('when no inputs are provided', () => {
-    it('throws an error', () => {
-      expect(() => predicateFromInputs(blankInputs)).toThrow(/predicate-type/i)
+    it('throws an error', async () => {
+      await expect(predicateFromInputs(blankInputs)).rejects.toThrow(
+        /predicate-type/i
+      )
     })
   })
 
   describe('when neither predicate path nor predicate are provided', () => {
-    it('throws an error', () => {
+    it('throws an error', async () => {
       const inputs: PredicateInputs = {
         ...blankInputs,
         predicateType: 'https://example.com/predicate'
       }
 
-      expect(() => predicateFromInputs(inputs)).toThrow(
+      await expect(predicateFromInputs(inputs)).rejects.toThrow(
         /one of predicate-path or predicate must be provided/i
       )
     })
   })
 
   describe('when both predicate path and predicate are provided', () => {
-    it('throws an error', () => {
+    it('throws an error', async () => {
       const inputs: PredicateInputs = {
         predicateType: 'https://example.com/predicate',
         predicate: '{}',
         predicatePath: 'path/to/predicate'
       }
 
-      expect(() => predicateFromInputs(inputs)).toThrow(
+      await expect(predicateFromInputs(inputs)).rejects.toThrow(
         /only one of predicate-path or predicate may be provided/i
       )
     })
@@ -65,13 +67,13 @@ describe('subjectFromInputs', () => {
       await fs.rm(path.parse(predicatePath).dir, { recursive: true })
     })
 
-    it('returns the predicate', () => {
+    it('returns the predicate', async () => {
       const inputs: PredicateInputs = {
         ...blankInputs,
         predicateType,
         predicatePath
       }
-      expect(predicateFromInputs(inputs)).toEqual({
+      await expect(predicateFromInputs(inputs)).resolves.toEqual({
         type: predicateType,
         params: JSON.parse(content)
       })
@@ -82,13 +84,15 @@ describe('subjectFromInputs', () => {
     const predicateType = 'https://example.com/predicate'
     const predicatePath = 'foo'
 
-    it('returns the predicate', () => {
+    it('returns the predicate', async () => {
       const inputs: PredicateInputs = {
         ...blankInputs,
         predicateType,
         predicatePath
       }
-      expect(() => predicateFromInputs(inputs)).toThrow(/file not found/)
+      await expect(predicateFromInputs(inputs)).rejects.toThrow(
+        /file not found/
+      )
     })
   })
 
@@ -96,14 +100,14 @@ describe('subjectFromInputs', () => {
     const predicateType = 'https://example.com/predicate'
     const content = '{}'
 
-    it('returns the predicate', () => {
+    it('returns the predicate', async () => {
       const inputs: PredicateInputs = {
         ...blankInputs,
         predicateType,
         predicate: content
       }
 
-      expect(predicateFromInputs(inputs)).toEqual({
+      await expect(predicateFromInputs(inputs)).resolves.toEqual({
         type: predicateType,
         params: JSON.parse(content)
       })
@@ -114,14 +118,14 @@ describe('subjectFromInputs', () => {
     const predicateType = 'https://example.com/predicate'
     const content = JSON.stringify({ a: 'a'.repeat(16 * 1024 * 1024) })
 
-    it('throws an error', () => {
+    it('throws an error', async () => {
       const inputs: PredicateInputs = {
         ...blankInputs,
         predicateType,
         predicate: content
       }
 
-      expect(() => predicateFromInputs(inputs)).toThrow(
+      await expect(predicateFromInputs(inputs)).rejects.toThrow(
         /predicate string exceeds maximum/
       )
     })

__tests__/provenance.test.ts

@@ -0,0 +1,48 @@
+import type { Predicate } from '@actions/attest'
+import { jest } from '@jest/globals'
+
+// Mock function
+const mockBuildSLSAProvenancePredicate = jest.fn<() => Promise<Predicate>>()
+
+// Mock @actions/attest
+jest.unstable_mockModule('@actions/attest', () => ({
+  buildSLSAProvenancePredicate: mockBuildSLSAProvenancePredicate
+}))
+
+// Dynamic import after mocking
+const { generateProvenancePredicate } = await import('../src/provenance')
+
+describe('generateProvenancePredicate', () => {
+  const mockPredicate = {
+    type: 'https://slsa.dev/provenance/v1',
+    params: {
+      buildDefinition: {
+        buildType: 'https://actions.github.io/buildtypes/workflow/v1'
+      },
+      runDetails: {
+        builder: { id: 'https://github.com/actions/runner' }
+      }
+    }
+  }
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+    mockBuildSLSAProvenancePredicate.mockResolvedValue(mockPredicate)
+  })
+
+  it('returns the SLSA provenance predicate', async () => {
+    const result = await generateProvenancePredicate()
+
+    expect(mockBuildSLSAProvenancePredicate).toHaveBeenCalledTimes(1)
+    expect(result).toEqual(mockPredicate)
+  })
+
+  it('propagates errors from buildSLSAProvenancePredicate', async () => {
+    const error = new Error('Failed to build provenance')
+    mockBuildSLSAProvenancePredicate.mockRejectedValue(error)
+
+    await expect(generateProvenancePredicate()).rejects.toThrow(
+      'Failed to build provenance'
+    )
+  })
+})

__tests__/sbom.test.ts

@@ -0,0 +1,161 @@
+import fs from 'fs/promises'
+import os from 'os'
+import path from 'path'
+import { parseSBOMFromPath, generateSBOMPredicate, SBOM } from '../src/sbom'
+
+describe('parseSBOMFromPath', () => {
+  let tmpDir: string
+
+  beforeEach(async () => {
+    tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'sbom-test-'))
+  })
+
+  afterEach(async () => {
+    await fs.rm(tmpDir, { recursive: true })
+  })
+
+  describe('when file does not exist', () => {
+    it('throws an error', async () => {
+      await expect(parseSBOMFromPath('/nonexistent/file.json')).rejects.toThrow(
+        /ENOENT/
+      )
+    })
+  })
+
+  describe('when file contains valid SPDX SBOM', () => {
+    const spdxSBOM = {
+      spdxVersion: 'SPDX-2.3',
+      SPDXID: 'SPDXRef-DOCUMENT',
+      name: 'test-package',
+      packages: []
+    }
+
+    it('returns SBOM with type spdx', async () => {
+      const filePath = path.join(tmpDir, 'sbom.spdx.json')
+      await fs.writeFile(filePath, JSON.stringify(spdxSBOM))
+
+      const result = await parseSBOMFromPath(filePath)
+
+      expect(result.type).toBe('spdx')
+      expect(result.object).toEqual(spdxSBOM)
+    })
+  })
+
+  describe('when file contains valid CycloneDX SBOM', () => {
+    const cyclonedxSBOM = {
+      bomFormat: 'CycloneDX',
+      specVersion: '1.4',
+      serialNumber: 'urn:uuid:12345',
+      components: []
+    }
+
+    it('returns SBOM with type cyclonedx', async () => {
+      const filePath = path.join(tmpDir, 'sbom.cdx.json')
+      await fs.writeFile(filePath, JSON.stringify(cyclonedxSBOM))
+
+      const result = await parseSBOMFromPath(filePath)
+
+      expect(result.type).toBe('cyclonedx')
+      expect(result.object).toEqual(cyclonedxSBOM)
+    })
+  })
+
+  describe('when file contains invalid SBOM format', () => {
+    it('throws an error', async () => {
+      const filePath = path.join(tmpDir, 'invalid.json')
+      await fs.writeFile(filePath, JSON.stringify({ random: 'data' }))
+
+      await expect(parseSBOMFromPath(filePath)).rejects.toThrow(
+        /Unsupported SBOM format/
+      )
+    })
+  })
+
+  describe('when file contains invalid JSON', () => {
+    it('throws an error', async () => {
+      const filePath = path.join(tmpDir, 'invalid.json')
+      await fs.writeFile(filePath, 'not valid json')
+
+      await expect(parseSBOMFromPath(filePath)).rejects.toThrow()
+    })
+  })
+
+  describe('when file exceeds maximum size', () => {
+    it('throws an error', async () => {
+      const filePath = path.join(tmpDir, 'large.json')
+      // Create a file larger than 16MB
+      const largeContent = 'x'.repeat(17 * 1024 * 1024)
+      await fs.writeFile(filePath, largeContent)
+
+      await expect(parseSBOMFromPath(filePath)).rejects.toThrow(
+        /SBOM file exceeds maximum allowed size/
+      )
+    })
+  })
+})
+
+describe('generateSBOMPredicate', () => {
+  describe('for SPDX SBOM', () => {
+    const spdxSBOM: SBOM = {
+      type: 'spdx',
+      object: {
+        spdxVersion: 'SPDX-2.3',
+        SPDXID: 'SPDXRef-DOCUMENT',
+        name: 'test-package'
+      }
+    }
+
+    it('returns predicate with correct SPDX type', () => {
+      const predicate = generateSBOMPredicate(spdxSBOM)
+
+      expect(predicate.type).toBe('https://spdx.dev/Document/v2.3')
+      expect(predicate.params).toEqual(spdxSBOM.object)
+    })
+  })
+
+  describe('for CycloneDX SBOM', () => {
+    const cyclonedxSBOM: SBOM = {
+      type: 'cyclonedx',
+      object: {
+        bomFormat: 'CycloneDX',
+        specVersion: '1.4',
+        serialNumber: 'urn:uuid:12345'
+      }
+    }
+
+    it('returns predicate with correct CycloneDX type', () => {
+      const predicate = generateSBOMPredicate(cyclonedxSBOM)
+
+      expect(predicate.type).toBe('https://cyclonedx.org/bom')
+      expect(predicate.params).toEqual(cyclonedxSBOM.object)
+    })
+  })
+
+  describe('for SPDX without version', () => {
+    const invalidSBOM: SBOM = {
+      type: 'spdx',
+      object: {
+        SPDXID: 'SPDXRef-DOCUMENT'
+      }
+    }
+
+    it('throws an error', () => {
+      expect(() => generateSBOMPredicate(invalidSBOM)).toThrow(
+        /Cannot find spdxVersion/
+      )
+    })
+  })
+
+  describe('for unsupported SBOM type', () => {
+    const unsupportedSBOM = {
+      type: 'unknown' as SBOM['type'],
+      object: { foo: 'bar' }
+    }
+
+    it('throws an error', () => {
+      expect(() => generateSBOMPredicate(unsupportedSBOM)).toThrow(
+        /Unsupported SBOM format/
+      )
+    })
+  })
+})

__tests__/subject.test.ts

@@ -524,6 +524,39 @@ f861e68a080799ca83104630b56abb90d8dbcc5f8b5a8639cb691e269838f29e  demo_0.0.1_lin
     })
   })
 
+  describe('when specifying a subject checksums string with duplicates', () => {
+    const checksums = `
+f861e68a080799ca83104630b56abb90d8dbcc5f8b5a8639cb691e269838f29e  demo_0.0.1_linux_386
+f861e68a080799ca83104630b56abb90d8dbcc5f8b5a8639cb691e269838f29e  demo_0.0.1_linux_386
+187dcd1506a170337415589ff00c8743f19d41cc31fca246c2739dfd450d0b9d *demo_0.0.1_linux_amd64`
+
+    it('returns de-duplicated subjects', async () => {
+      const inputs: SubjectInputs = {
+        ...blankInputs,
+        subjectChecksums: checksums
+      }
+      const subjects = await subjectFromInputs(inputs)
+
+      expect(subjects).toBeDefined()
+      expect(subjects).toHaveLength(2)
+
+      expect(subjects).toContainEqual({
+        name: 'demo_0.0.1_linux_386',
+        digest: {
+          sha256:
+            'f861e68a080799ca83104630b56abb90d8dbcc5f8b5a8639cb691e269838f29e'
+        }
+      })
+      expect(subjects).toContainEqual({
+        name: 'demo_0.0.1_linux_amd64',
+        digest: {
+          sha256:
+            '187dcd1506a170337415589ff00c8743f19d41cc31fca246c2739dfd450d0b9d'
+        }
+      })
+    })
+  })
+
   describe('when specifying a subject checksums string with an unrecognized digest', () => {
     const checksums = `f861e  demo_0.0.1_linux_386`
 

action.yml

@@ -30,21 +30,29 @@ inputs:
       attestation. Must specify exactly one of "subject-path", "subject-digest",
       or "subject-checksums".
     required: false
+  sbom-path:
+    description: >
+      Path to the JSON-formatted SBOM file (SPDX or CycloneDX) to attest.
+      File size cannot exceed 16MB. When provided, creates an SBOM attestation.
+      Cannot be used together with "predicate-type", "predicate", or
+      "predicate-path".
+    required: false
   predicate-type:
     description: >
-      URI identifying the type of the predicate.
-    required: true
+      URI identifying the type of the predicate. Required when using "predicate"
+      or "predicate-path" for custom attestations.
+    required: false
   predicate:
     description: >
       String containing the value for the attestation predicate. String length
       cannot exceed 16MB. Must supply exactly one of "predicate-path" or
-      "predicate".
+      "predicate" when creating custom attestations.
     required: false
   predicate-path:
     description: >
       Path to the file which contains the content for the attestation predicate.
       File size cannot exceed 16MB. Must supply exactly one of "predicate-path"
-      or "predicate".
+      or "predicate" when creating custom attestations.
     required: false
   push-to-registry:
     description: >

dist/606.index.js

@@ -1,7 +1,6 @@
-"use strict";
-exports.id = 606;
-exports.ids = [606];
-exports.modules = {
+export const id = 606;
+export const ids = [606];
+export const modules = {
 
 /***/ 606:
 /***/ ((__unused_webpack___webpack_module__, __webpack_exports__, __webpack_require__) => {
@@ -19,7 +18,7 @@ async function pMap(
 		signal,
 	} = {},
 ) {
-	return new Promise((resolve, reject_) => {
+	return new Promise((resolve_, reject_) => {
 		if (iterable[Symbol.iterator] === undefined && iterable[Symbol.asyncIterator] === undefined) {
 			throw new TypeError(`Expected \`input\` to be either an \`Iterable\` or \`AsyncIterable\`, got (${typeof iterable})`);
 		}
@@ -42,10 +41,24 @@ async function pMap(
 		let currentIndex = 0;
 		const iterator = iterable[Symbol.iterator] === undefined ? iterable[Symbol.asyncIterator]() : iterable[Symbol.iterator]();
 
+		const signalListener = () => {
+			reject(signal.reason);
+		};
+
+		const cleanup = () => {
+			signal?.removeEventListener('abort', signalListener);
+		};
+
+		const resolve = value => {
+			resolve_(value);
+			cleanup();
+		};
+
 		const reject = reason => {
 			isRejected = true;
 			isResolved = true;
 			reject_(reason);
+			cleanup();
 		};
 
 		if (signal) {
@@ -53,9 +66,7 @@ async function pMap(
 				reject(signal.reason);
 			}
 
-			signal.addEventListener('abort', () => {
-				reject(signal.reason);
-			});
+			signal.addEventListener('abort', signalListener, {once: true});
 		}
 
 		const next = async () => {
@@ -203,31 +214,32 @@ function pMapIterable(
 			const iterator = iterable[Symbol.asyncIterator] === undefined ? iterable[Symbol.iterator]() : iterable[Symbol.asyncIterator]();
 
 			const promises = [];
-			let runningMappersCount = 0;
+			let pendingPromisesCount = 0;
 			let isDone = false;
 			let index = 0;
 
 			function trySpawn() {
-				if (isDone || !(runningMappersCount < concurrency && promises.length < backpressure)) {
+				if (isDone || !(pendingPromisesCount < concurrency && promises.length < backpressure)) {
 					return;
 				}
 
+				pendingPromisesCount++;
+
 				const promise = (async () => {
 					const {done, value} = await iterator.next();
 
 					if (done) {
+						pendingPromisesCount--;
 						return {done: true};
 					}
 
-					runningMappersCount++;
-
 					// Spawn if still below concurrency and backpressure limit
 					trySpawn();
 
 					try {
 						const returnValue = await mapper(await value, index++);
 
-						runningMappersCount--;
+						pendingPromisesCount--;
 
 						if (returnValue === pMapSkip) {
 							const index = promises.indexOf(promise);
@@ -242,6 +254,7 @@ function pMapIterable(
 
 						return {done: false, value: returnValue};
 					} catch (error) {
+						pendingPromisesCount--;
 						isDone = true;
 						return {error};
 					}
@@ -284,4 +297,3 @@ const pMapSkip = Symbol('skip');
 /***/ })
 
 };
-;

dist/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

jest.setup.js

@@ -1 +1,3 @@
+import { jest } from '@jest/globals'
+
 process.stdout.write = jest.fn()

package.json

@@ -4,6 +4,7 @@
   "version": "3.2.0",
   "author": "",
   "private": true,
+  "type": "module",
   "homepage": "https://github.com/actions/attest",
   "repository": {
     "type": "git",
@@ -24,7 +25,7 @@
   },
   "scripts": {
     "bundle": "npm run format:write && npm run package",
-    "ci-test": "jest",
+    "ci-test": "NODE_OPTIONS='--experimental-vm-modules' jest",
     "format:write": "prettier --write **/*.ts",
     "format:check": "prettier --check **/*.ts",
     "lint:eslint": "npx eslint",
@@ -32,12 +33,15 @@
     "lint": "npm run lint:eslint && npm run lint:markdown",
     "package": "ncc build src/index.ts --license licenses.txt",
     "package:watch": "npm run package -- --watch",
-    "test": "jest",
+    "test": "NODE_OPTIONS='--experimental-vm-modules' jest",
     "all": "npm run format:write && npm run lint && npm run test && npm run package"
   },
   "license": "MIT",
   "jest": {
-    "preset": "ts-jest",
+    "preset": "ts-jest/presets/default-esm",
+    "extensionsToTreatAsEsm": [
+      ".ts"
+    ],
     "setupFilesAfterEnv": [
       "./jest.setup.js"
     ],
@@ -56,7 +60,12 @@
       "/dist/"
     ],
     "transform": {
-      "^.+\\.ts$": "ts-jest"
+      "^.+\\.ts$": [
+        "ts-jest",
+        {
+          "useESM": true
+        }
+      ]
     },
     "coverageReporters": [
       "json-summary",
@@ -69,31 +78,32 @@
     ]
   },
   "dependencies": {
-    "@actions/attest": "^2.1.0",
-    "@actions/core": "^2.0.1",
-    "@actions/github": "^6.0.1",
-    "@actions/glob": "^0.5.0",
+    "@actions/attest": "^3.0.0",
+    "@actions/core": "^3.0.0",
+    "@actions/github": "^9.0.0",
+    "@actions/glob": "^0.6.1",
     "@sigstore/oci": "^0.6.0",
     "csv-parse": "^5.6.0"
   },
   "devDependencies": {
     "@eslint/js": "^9.39.2",
+    "@jest/globals": "^30.2.0",
     "@sigstore/mock": "^0.11.0",
     "@types/jest": "^30.0.0",
     "@types/make-fetch-happen": "^10.0.4",
-    "@types/node": "^25.0.3",
+    "@types/node": "^25.2.0",
     "@vercel/ncc": "^0.38.4",
     "eslint": "^9.39.2",
     "eslint-plugin-import": "^2.32.0",
-    "eslint-plugin-jest": "^29.9.0",
+    "eslint-plugin-jest": "^29.12.1",
     "jest": "^30.2.0",
     "js-yaml": "^4.1.1",
     "markdownlint-cli": "^0.47.0",
     "nock": "^13.5.6",
-    "prettier": "^3.7.4",
+    "prettier": "^3.8.1",
     "ts-jest": "^29.4.6",
     "typescript": "^5.9.3",
-    "typescript-eslint": "^8.50.1",
-    "undici": "^7.18.2"
+    "typescript-eslint": "^8.54.0",
+    "undici": "^7.20.0"
   }
 }

src/attest.ts

@@ -5,10 +5,10 @@ import {
   attest,
   createStorageRecord
 } from '@actions/attest'
-import { attachArtifactToImage, getRegistryCredentials } from '@sigstore/oci'
-import { formatSubjectDigest } from './subject'
 import * as core from '@actions/core'
 import * as github from '@actions/github'
+import { attachArtifactToImage, getRegistryCredentials } from '@sigstore/oci'
+import { formatSubjectDigest } from './subject'
 
 const OCI_TIMEOUT = 30000
 const OCI_RETRY = 3

src/detect.ts

@@ -0,0 +1,45 @@
+export type AttestationType = 'provenance' | 'sbom' | 'custom'
+
+export type DetectionInputs = {
+  sbomPath: string
+  predicateType: string
+  predicate: string
+  predicatePath: string
+}
+
+export const detectAttestationType = (
+  inputs: DetectionInputs
+): AttestationType => {
+  const { sbomPath, predicateType, predicate, predicatePath } = inputs
+
+  // SBOM mode takes priority
+  if (sbomPath) {
+    return 'sbom'
+  }
+
+  // Custom mode when any predicate inputs are provided
+  if (predicateType || predicate || predicatePath) {
+    return 'custom'
+  }
+
+  // Default to provenance mode
+  return 'provenance'
+}
+
+export const validateAttestationInputs = (inputs: DetectionInputs): void => {
+  const { sbomPath, predicateType, predicate, predicatePath } = inputs
+
+  // Cannot combine sbom-path with predicate inputs
+  if (sbomPath && (predicateType || predicate || predicatePath)) {
+    throw new Error(
+      'Cannot specify sbom-path together with predicate-type, predicate, or predicate-path'
+    )
+  }
+
+  // Custom mode requires predicate-type
+  if ((predicate || predicatePath) && !predicateType) {
+    throw new Error(
+      'predicate-type is required when using predicate or predicate-path'
+    )
+  }
+}

src/index.ts

@@ -9,6 +9,7 @@ const inputs: RunInputs = {
   subjectName: core.getInput('subject-name'),
   subjectDigest: core.getInput('subject-digest'),
   subjectChecksums: core.getInput('subject-checksums'),
+  sbomPath: core.getInput('sbom-path'),
   predicateType: core.getInput('predicate-type'),
   predicate: core.getInput('predicate'),
   predicatePath: core.getInput('predicate-path'),

src/main.ts

@@ -1,11 +1,19 @@
 import * as core from '@actions/core'
 import * as github from '@actions/github'
-import fs from 'fs'
+import fs from 'fs/promises'
 import os from 'os'
 import path from 'path'
 import { AttestResult, SigstoreInstance, createAttestation } from './attest'
+import {
+  AttestationType,
+  DetectionInputs,
+  detectAttestationType,
+  validateAttestationInputs
+} from './detect'
 import { SEARCH_PUBLIC_GOOD_URL } from './endpoints'
 import { PredicateInputs, predicateFromInputs } from './predicate'
+import { generateProvenancePredicate } from './provenance'
+import { generateSBOMPredicate, parseSBOMFromPath } from './sbom'
 import * as style from './style'
 import {
   SubjectInputs,
@@ -13,13 +21,18 @@ import {
   subjectFromInputs
 } from './subject'
 
-import type { Subject } from '@actions/attest'
+import type { Predicate, Subject } from '@actions/attest'
 
 const ATTESTATION_FILE_NAME = 'attestation.json'
 const ATTESTATION_PATHS_FILE_NAME = 'created_attestation_paths.txt'
 
+export type SBOMInputs = {
+  sbomPath: string
+}
+
 export type RunInputs = SubjectInputs &
-  PredicateInputs & {
+  PredicateInputs &
+  SBOMInputs & {
     pushToRegistry: boolean
     createStorageRecord: boolean
     githubToken: string
@@ -58,13 +71,26 @@ export async function run(inputs: RunInputs): Promise<void> {
       )
     }
 
+    // Detect attestation type and validate inputs
+    const detectionInputs: DetectionInputs = {
+      sbomPath: inputs.sbomPath,
+      predicateType: inputs.predicateType,
+      predicate: inputs.predicate,
+      predicatePath: inputs.predicatePath
+    }
+    validateAttestationInputs(detectionInputs)
+    const attestationType = detectAttestationType(detectionInputs)
+    logAttestationType(attestationType)
+
     const subjects = await subjectFromInputs({
       ...inputs,
       downcaseName: inputs.pushToRegistry
     })
-    const predicate = predicateFromInputs(inputs)
 
-    const outputPath = path.join(tempDir(), ATTESTATION_FILE_NAME)
+    // Generate predicate based on attestation type
+    const predicate = await getPredicateForType(attestationType, inputs)
+
+    const outputPath = path.join(await tempDir(), ATTESTATION_FILE_NAME)
     core.setOutput('bundle-path', outputPath)
 
     const att = await createAttestation(subjects, predicate, {
@@ -77,7 +103,7 @@ export async function run(inputs: RunInputs): Promise<void> {
     logAttestation(subjects, att, sigstoreInstance)
 
     // Write attestation bundle to output file
-    fs.writeFileSync(outputPath, JSON.stringify(att.bundle) + os.EOL, {
+    await fs.writeFile(outputPath, JSON.stringify(att.bundle) + os.EOL, {
       encoding: 'utf-8',
       flag: 'a'
     })
@@ -87,7 +113,7 @@ export async function run(inputs: RunInputs): Promise<void> {
     if (baseDir) {
       const outputSummaryPath = path.join(baseDir, ATTESTATION_PATHS_FILE_NAME)
       // Append the output path to the attestations paths file
-      fs.appendFileSync(outputSummaryPath, outputPath + os.EOL, {
+      await fs.appendFile(outputSummaryPath, outputPath + os.EOL, {
         encoding: 'utf-8',
         flag: 'a'
       })
@@ -102,6 +128,7 @@ export async function run(inputs: RunInputs): Promise<void> {
       core.setOutput('attestation-id', att.attestationID)
       core.setOutput('attestation-url', attestationURL(att.attestationID))
     }
+
     if (att.storageRecordIds) {
       core.setOutput('storage-record-ids', att.storageRecordIds.join(','))
     }
@@ -194,7 +221,7 @@ const logSummary = async (attestation: AttestResult): Promise<void> => {
   }
 }
 
-const tempDir = (): string => {
+const tempDir = async (): Promise<string> => {
   const basePath = process.env['RUNNER_TEMP']
 
   /* istanbul ignore if */
@@ -202,8 +229,35 @@ const tempDir = (): string => {
     throw new Error('Missing RUNNER_TEMP environment variable')
   }
 
-  return fs.mkdtempSync(path.join(basePath, path.sep))
+  return fs.mkdtemp(path.join(basePath, path.sep))
 }
 
 const attestationURL = (id: string): string =>
   `${github.context.serverUrl}/${github.context.repo.owner}/${github.context.repo.repo}/attestations/${id}`
+
+// Log the detected attestation type
+const logAttestationType = (type: AttestationType): void => {
+  const typeLabels: Record<AttestationType, string> = {
+    provenance: 'Build Provenance',
+    sbom: 'SBOM',
+    custom: 'Custom'
+  }
+  core.info(`Attestation type: ${typeLabels[type]}`)
+}
+
+// Generate predicate based on attestation type
+const getPredicateForType = async (
+  type: AttestationType,
+  inputs: RunInputs
+): Promise<Predicate> => {
+  switch (type) {
+    case 'provenance':
+      return generateProvenancePredicate()
+    case 'sbom': {
+      const sbom = await parseSBOMFromPath(inputs.sbomPath)
+      return generateSBOMPredicate(sbom)
+    }
+    case 'custom':
+      return predicateFromInputs(inputs)
+  }
+}

src/predicate.ts

@@ -1,4 +1,4 @@
-import fs from 'fs'
+import fs from 'fs/promises'
 
 import type { Predicate } from '@actions/attest'
 
@@ -12,7 +12,9 @@ const MAX_PREDICATE_SIZE_BYTES = 16 * 1024 * 1024
 
 // Returns the predicate specified by the action's inputs. The predicate value
 // may be specified as a path to a file or as a string.
-export const predicateFromInputs = (inputs: PredicateInputs): Predicate => {
+export const predicateFromInputs = async (
+  inputs: PredicateInputs
+): Promise<Predicate> => {
   const { predicateType, predicate, predicatePath } = inputs
 
   if (!predicateType) {
@@ -30,18 +32,22 @@ export const predicateFromInputs = (inputs: PredicateInputs): Predicate => {
   let params: string = predicate
 
   if (predicatePath) {
-    if (!fs.existsSync(predicatePath)) {
+    try {
+      await fs.access(predicatePath)
+    } catch {
       throw new Error(`predicate file not found: ${predicatePath}`)
     }
 
+    const stat = await fs.stat(predicatePath)
+
     /* istanbul ignore next */
-    if (fs.statSync(predicatePath).size > MAX_PREDICATE_SIZE_BYTES) {
+    if (stat.size > MAX_PREDICATE_SIZE_BYTES) {
       throw new Error(
         `predicate file exceeds maximum allowed size: ${MAX_PREDICATE_SIZE_BYTES} bytes`
       )
     }
 
-    params = fs.readFileSync(predicatePath, 'utf-8')
+    params = await fs.readFile(predicatePath, 'utf-8')
   } else {
     if (predicate.length > MAX_PREDICATE_SIZE_BYTES) {
       throw new Error(

src/provenance.ts

@@ -0,0 +1,7 @@
+import { buildSLSAProvenancePredicate } from '@actions/attest'
+
+import type { Predicate } from '@actions/attest'
+
+export const generateProvenancePredicate = async (): Promise<Predicate> => {
+  return buildSLSAProvenancePredicate()
+}

src/sbom.ts

@@ -0,0 +1,87 @@
+import fs from 'fs/promises'
+
+import type { Predicate } from '@actions/attest'
+
+export type SBOM = {
+  type: 'spdx' | 'cyclonedx'
+  object: object
+}
+
+// SBOMs cannot exceed 16MB.
+const MAX_SBOM_SIZE_BYTES = 16 * 1024 * 1024
+
+export const parseSBOMFromPath = async (filePath: string): Promise<SBOM> => {
+  const fileContent = await fs.readFile(filePath, 'utf8')
+
+  const stats = await fs.stat(filePath)
+  if (stats.size > MAX_SBOM_SIZE_BYTES) {
+    throw new Error(
+      `SBOM file exceeds maximum allowed size: ${MAX_SBOM_SIZE_BYTES} bytes`
+    )
+  }
+
+  const sbom = JSON.parse(fileContent) as object
+
+  if (checkIsSPDX(sbom)) {
+    return { type: 'spdx', object: sbom }
+  } else if (checkIsCycloneDX(sbom)) {
+    return { type: 'cyclonedx', object: sbom }
+  }
+
+  throw new Error(
+    'Unsupported SBOM format. Must be valid SPDX or CycloneDX JSON.'
+  )
+}
+
+const checkIsSPDX = (sbomObject: {
+  spdxVersion?: string
+  SPDXID?: string
+}): boolean => {
+  return !!(sbomObject?.spdxVersion && sbomObject?.SPDXID)
+}
+
+const checkIsCycloneDX = (sbomObject: {
+  bomFormat?: string
+  serialNumber?: string
+  specVersion?: string
+}): boolean => {
+  return !!(
+    sbomObject?.bomFormat &&
+    sbomObject?.serialNumber &&
+    sbomObject?.specVersion
+  )
+}
+
+export const generateSBOMPredicate = (sbom: SBOM): Predicate => {
+  switch (sbom.type) {
+    case 'spdx':
+      return generateSPDXPredicate(sbom.object)
+    case 'cyclonedx':
+      return generateCycloneDXPredicate(sbom.object)
+    default:
+      throw new Error('Unsupported SBOM format')
+  }
+}
+
+// ref: https://github.com/in-toto/attestation/blob/main/spec/predicates/spdx.md
+const generateSPDXPredicate = (sbom: object): Predicate => {
+  const spdxVersion = (sbom as { spdxVersion?: string })?.['spdxVersion']
+  if (!spdxVersion) {
+    throw new Error('Cannot find spdxVersion in the SBOM')
+  }
+
+  const version = spdxVersion.split('-')[1]
+
+  return {
+    type: `https://spdx.dev/Document/v${version}`,
+    params: sbom
+  }
+}
+
+// ref: https://github.com/in-toto/attestation/blob/main/spec/predicates/cyclonedx.md
+const generateCycloneDXPredicate = (sbom: object): Predicate => {
+  return {
+    type: 'https://cyclonedx.org/bom',
+    params: sbom
+  }
+}

src/subject.ts

@@ -2,7 +2,8 @@ import * as glob from '@actions/glob'
 import assert from 'assert'
 import crypto from 'crypto'
 import { parse } from 'csv-parse/sync'
-import fs from 'fs'
+import { createReadStream } from 'fs'
+import fs from 'fs/promises'
 import os from 'os'
 import path from 'path'
 
@@ -64,7 +65,7 @@ export const subjectFromInputs = async (
     case !!subjectDigest:
       return [getSubjectFromDigest(subjectDigest, name)]
     case !!subjectChecksums:
-      return getSubjectFromChecksums(subjectChecksums)
+      return await getSubjectFromChecksums(subjectChecksums)
     /* istanbul ignore next */
     default:
       // This should be unreachable, but TS requires a default case
@@ -93,13 +94,18 @@ const getSubjectFromPath = async (
   // Expand the globbed paths to a list of actual paths
   const paths = await glob.create(subjectPaths).then(async g => g.glob())
 
-  // Filter path list to just the files (not directories)
-  const files = paths.filter(p => fs.statSync(p).isFile())
-
-  if (files.length > MAX_SUBJECT_COUNT) {
-    throw new Error(
-      `Too many subjects specified. The maximum number of subjects is ${MAX_SUBJECT_COUNT}.`
-    )
+  // Filter path list to just the files (not directories), enforcing the maximum
+  const files: string[] = []
+  for (const p of paths) {
+    const stat = await fs.stat(p)
+    if (stat.isFile()) {
+      if (files.length >= MAX_SUBJECT_COUNT) {
+        throw new Error(
+          `Too many subjects specified (>${MAX_SUBJECT_COUNT}). The maximum number of subjects is ${MAX_SUBJECT_COUNT}.`
+        )
+      }
+      files.push(p)
+    }
   }
 
   for (const file of files) {
@@ -142,16 +148,21 @@ const getSubjectFromDigest = (
   }
 }
 
-const getSubjectFromChecksums = (subjectChecksums: string): Subject[] => {
-  if (fs.existsSync(subjectChecksums)) {
+const getSubjectFromChecksums = async (
+  subjectChecksums: string
+): Promise<Subject[]> => {
+  try {
+    await fs.access(subjectChecksums)
     return getSubjectFromChecksumsFile(subjectChecksums)
-  } else {
+  } catch {
     return getSubjectFromChecksumsString(subjectChecksums)
   }
 }
 
-const getSubjectFromChecksumsFile = (checksumsPath: string): Subject[] => {
-  const stats = fs.statSync(checksumsPath)
+const getSubjectFromChecksumsFile = async (
+  checksumsPath: string
+): Promise<Subject[]> => {
+  const stats = await fs.stat(checksumsPath)
   if (!stats.isFile()) {
     throw new Error(`subject checksums file not found: ${checksumsPath}`)
   }
@@ -163,7 +174,7 @@ const getSubjectFromChecksumsFile = (checksumsPath: string): Subject[] => {
     )
   }
 
-  const checksums = fs.readFileSync(checksumsPath, 'utf-8')
+  const checksums = await fs.readFile(checksumsPath, 'utf-8')
   return getSubjectFromChecksumsString(checksums)
 }
 
@@ -195,10 +206,15 @@ const getSubjectFromChecksumsString = (checksums: string): Subject[] => {
       throw new Error(`Invalid digest: ${digest}`)
     }
 
-    subjects.push({
-      name,
-      digest: { [digestAlgorithm(digest)]: digest }
-    })
+    const alg = digestAlgorithm(digest)
+
+    // Only add the subject if it is not already in the list (deduplicate by name & digest)
+    if (!subjects.some(s => s.name === name && s.digest[alg] === digest)) {
+      subjects.push({
+        name,
+        digest: { [alg]: digest }
+      })
+    }
   }
 
   return subjects
@@ -213,7 +229,7 @@ const digestFile = async (
 ): Promise<string> => {
   return new Promise((resolve, reject) => {
     const hash = crypto.createHash(algorithm).setEncoding('hex')
-    fs.createReadStream(filePath)
+    createReadStream(filePath)
       .once('error', reject)
       .pipe(hash)
       .once('finish', () => resolve(hash.read()))

tsconfig.json

@@ -2,9 +2,9 @@
   "$schema": "https://json.schemastore.org/tsconfig",
   "compilerOptions": {
     "target": "ES2022",
-    "module": "NodeNext",
+    "module": "ESNext",
     "rootDir": "./src",
-    "moduleResolution": "NodeNext",
+    "moduleResolution": "Bundler",
     "isolatedModules": true,
     "baseUrl": "./",
     "sourceMap": true,