Replace cron info diagnostics with inlay hints (#270)

- Remove DiagnosticSeverity.Information for valid cron expressions
- Add new inlay-hints.ts module with getInlayHints() function
- Register inlayHintProvider capability in language server
- Display human-readable cron descriptions as inline hints

Related #269

languageservice/src/index.ts

@@ -2,6 +2,7 @@ export {complete} from "./complete.js";
 export {ContextProviderConfig} from "./context-providers/config.js";
 export {documentLinks} from "./document-links.js";
 export {hover} from "./hover.js";
+export {getInlayHints} from "./inlay-hints.js";
 export {Logger, LogLevel, registerLogger, setLogLevel} from "./log.js";
 export {validate, ValidationConfig, ActionsMetadataProvider} from "./validate.js";
 export {ValueProviderConfig, ValueProviderKind} from "./value-providers/config.js";

languageservice/src/inlay-hints.test.ts

@@ -0,0 +1,116 @@
+import {InlayHintKind} from "vscode-languageserver-types";
+import {getInlayHints} from "./inlay-hints.js";
+import {registerLogger} from "./log.js";
+import {createDocument} from "./test-utils/document.js";
+import {TestLogger} from "./test-utils/logger.js";
+import {clearCache} from "./utils/workflow-cache.js";
+
+registerLogger(new TestLogger());
+
+beforeEach(() => {
+  clearCache();
+});
+
+describe("inlay-hints", () => {
+  describe("cron expressions", () => {
+    it("returns inlay hint for valid cron expression", () => {
+      const input = `on:
+  schedule:
+    - cron: '0 * * * *'
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(1);
+      expect(hints[0].label).toBe("→ Runs every hour");
+      expect(hints[0].kind).toBe(InlayHintKind.Parameter);
+      expect(hints[0].paddingLeft).toBe(true);
+    });
+
+    it("returns correct position at end of cron value", () => {
+      const input = `on:
+  schedule:
+    - cron: '0 3 * * 1'
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(1);
+      // Position should be at the end of the cron string value (after the closing quote)
+      // Line 3 (0-indexed: 2), end of '0 3 * * 1'
+      expect(hints[0].position.line).toBe(2);
+    });
+
+    it("returns no hint for invalid cron expression", () => {
+      const input = `on:
+  schedule:
+    - cron: 'invalid cron'
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(0);
+    });
+
+    it("returns multiple hints for multiple cron expressions", () => {
+      const input = `on:
+  schedule:
+    - cron: '0 * * * *'
+    - cron: '0 0 * * *'
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(2);
+      expect(hints[0].label).toBe("→ Runs every hour");
+      expect(hints[1].label).toBe("→ Runs at 00:00");
+    });
+
+    it("returns hint with descriptive label for weekly cron", () => {
+      const input = `on:
+  schedule:
+    - cron: '0 3 * * 1'
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(1);
+      expect(hints[0].label).toContain("Monday");
+    });
+
+    it("returns no hints for empty workflow", () => {
+      const input = ``;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(0);
+    });
+
+    it("returns no hints for workflow without schedule", () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo hello
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(0);
+    });
+
+    it("returns hint for frequent cron that triggers warning", () => {
+      // Even crons that trigger the <5min warning should still get inlay hints
+      const input = `on:
+  schedule:
+    - cron: '* * * * *'
+`;
+      const document = createDocument("test.yaml", input);
+      const hints = getInlayHints(document);
+
+      expect(hints).toHaveLength(1);
+      expect(hints[0].label).toBe("→ Runs every minute");
+    });
+  });
+});

languageservice/src/inlay-hints.ts

@@ -0,0 +1,56 @@
+import {isString} from "@actions/workflow-parser";
+import {getCronDescription} from "@actions/workflow-parser/model/converter/cron";
+import {TemplateToken} from "@actions/workflow-parser/templates/tokens/template-token";
+import {File} from "@actions/workflow-parser/workflows/file";
+import {TextDocument} from "vscode-languageserver-textdocument";
+import {InlayHint, InlayHintKind} from "vscode-languageserver-types";
+import {fetchOrParseWorkflow} from "./utils/workflow-cache.js";
+
+/**
+ * Returns inlay hints for a workflow document.
+ * Currently supports cron expressions, showing a human-readable description
+ * of the schedule inline after the cron value.
+ *
+ * @param document Text document to get inlay hints for
+ * @returns Array of inlay hints
+ */
+export function getInlayHints(document: TextDocument): InlayHint[] {
+  const file: File = {
+    name: document.uri,
+    content: document.getText()
+  };
+
+  const result = fetchOrParseWorkflow(file, document.uri);
+  if (!result?.value) {
+    return [];
+  }
+
+  const hints: InlayHint[] = [];
+
+  // Traverse the workflow AST to find cron expressions
+  for (const [parent, token, key] of TemplateToken.traverse(result.value)) {
+    const validationToken = key || parent || token;
+    const validationDefinition = validationToken.definition;
+
+    // Check for cron-pattern tokens
+    if (isString(token) && token.range && validationDefinition?.key === "cron-pattern") {
+      const cronValue = token.value;
+      const description = getCronDescription(cronValue);
+
+      if (description) {
+        // Position the hint at the end of the cron value
+        hints.push({
+          position: {
+            line: token.range.end.line - 1, // Convert from 1-based to 0-based
+            character: token.range.end.column - 1 // Convert from 1-based to 0-based
+          },
+          label: `→ ${description}`,
+          kind: InlayHintKind.Parameter,
+          paddingLeft: true
+        });
+      }
+    }
+  }
+
+  return hints;
+}

languageservice/src/validate.test.ts

@@ -231,7 +231,7 @@ jobs:
     } as Diagnostic);
   });
 
-  it("cron with interval of 5 minutes or more shows info", async () => {
+  it("cron with interval of 5 minutes or more shows no diagnostic", async () => {
     const result = await validate(
       createDocument(
         "wf.yaml",
@@ -245,25 +245,7 @@ jobs:
       {valueProviderConfig: defaultValueProviders}
     );
 
-    expect(result.length).toBe(1);
-    expect(result[0]).toEqual({
-      message: "Runs every 5 minutes",
-      severity: DiagnosticSeverity.Information,
-      code: "on-schedule",
-      codeDescription: {
-        href: "https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule"
-      },
-      range: {
-        end: {
-          character: 25,
-          line: 2
-        },
-        start: {
-          character: 12,
-          line: 2
-        }
-      }
-    } as Diagnostic);
+    expect(result.length).toBe(0);
   });
 
   it("cron with comma-separated minutes less than 5 apart shows warning", async () => {

languageservice/src/validate.ts

@@ -258,17 +258,6 @@ function validateCronExpression(diagnostics: Diagnostic[], token: StringToken):
         href: CRON_SCHEDULE_DOCS_URL
       }
     });
-  } else {
-    // Show info message for valid cron expressions
-    diagnostics.push({
-      message: description,
-      range: mapRange(token.range),
-      severity: DiagnosticSeverity.Information,
-      code: "on-schedule",
-      codeDescription: {
-        href: CRON_SCHEDULE_DOCS_URL
-      }
-    });
   }
 }