Show cron description on hover (#291)

Related #286 - When hovering over a cron expression, show the human-readable
description instead of empty content. Users who have inlay hints disabled
can now still see the cron description.

languageservice/src/hover.test.ts

@@ -110,8 +110,7 @@ jobs:
 `;
     const result = await hover(...getPositionFromCursor(input));
     expect(result).not.toBeUndefined();
-    // Cron description is now shown via diagnostics, not hover
-    expect(result?.contents).toEqual("");
+    expect(result?.contents).toEqual("Runs at 0 and 30 minutes past the hour, at 00:00 and 12:00");
   });
 
   it("on a cron mapping key", async () => {

languageservice/src/hover.ts

@@ -2,6 +2,8 @@ import {data, DescriptionDictionary, Parser} from "@actions/expressions";
 import {FunctionDefinition, FunctionInfo} from "@actions/expressions/funcs/info";
 import {Lexer} from "@actions/expressions/lexer";
 import {parseAction} from "@actions/workflow-parser/actions/action-parser";
+import {isString} from "@actions/workflow-parser";
+import {getCronDescription} from "@actions/workflow-parser/model/converter/cron";
 import {ErrorPolicy} from "@actions/workflow-parser/model/convert";
 import {splitAllowedContext} from "@actions/workflow-parser/templates/allowed-context";
 import {TemplateToken} from "@actions/workflow-parser/templates/tokens/template-token";
@@ -134,6 +136,17 @@ export async function hover(document: TextDocument, position: Position, config?:
   // Non-expression hover: show the schema description for the YAML key or value
   info(`Calculating hover for token with definition ${hoverToken.definition.key}`);
 
+  // Check for cron expression hover
+  if (isString(hoverToken) && hoverToken.definition.key === "cron-pattern") {
+    const cronDescription = getCronDescription(hoverToken.value);
+    if (cronDescription) {
+      return {
+        contents: cronDescription,
+        range: mapRange(hoverToken.range)
+      };
+    }
+  }
+
   let description: string;
   if (!isAction && tokenResult.parent && isReusableWorkflowJobInput(tokenResult)) {
     // Reusable workflow call: fetch the called workflow's input descriptions