Warn when CODEQL_ACTION_CLEANUP_TRAP_CACHES is set

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

src/analyze-action.ts

@@ -49,7 +49,10 @@ import {
   getActionsStatus,
   StatusReportBase,
 } from "./status-report";
-import { uploadTrapCaches } from "./trap-caching";
+import {
+  uploadTrapCaches,
+  warnIfTrapCacheCleanupEnvVarIsSet,
+} from "./trap-caching";
 import * as uploadLib from "./upload-lib";
 import { UploadResult } from "./upload-lib";
 import { postProcessAndUploadSarif } from "./upload-sarif";
@@ -270,6 +273,8 @@ async function run(action: ActionState<["Base", "Logger", "Env", "Actions"]>) {
       );
     }
 
+    warnIfTrapCacheCleanupEnvVarIsSet(action);
+
     const apiDetails = getApiDetails();
     const outputDir = actionsUtil.getRequiredInput("output");
     action.env.export(EnvVar.SARIF_RESULTS_OUTPUT_DIR, outputDir);

src/trap-caching.test.ts

@@ -15,6 +15,7 @@ import * as configUtils from "./config-utils";
 import * as gitUtils from "./git-utils";
 import { BuiltInLanguage } from "./languages";
 import {
+  callee,
   createTestConfig,
   getRecordingLogger,
   makeVersionInfo,
@@ -24,6 +25,7 @@ import {
   downloadTrapCaches,
   getLanguagesSupportingCaching,
   uploadTrapCaches,
+  warnIfTrapCacheCleanupEnvVarIsSet,
 } from "./trap-caching";
 import * as util from "./util";
 
@@ -194,3 +196,28 @@ test.serial(
     });
   },
 );
+
+// `CODEQL_ACTION_CLEANUP_TRAP_CACHES` has no effect with either value, so we warn even when it's
+// set to `false`.
+for (const value of ["true", "false"]) {
+  test(`warnIfTrapCacheCleanupEnvVarIsSet warns when CODEQL_ACTION_CLEANUP_TRAP_CACHES is '${value}'`, async (t) => {
+    const target = callee(warnIfTrapCacheCleanupEnvVarIsSet)
+      .withEnv((env) => env.set("CODEQL_ACTION_CLEANUP_TRAP_CACHES", value))
+      .withArgs()
+      .logs(
+        t,
+        "CODEQL_ACTION_CLEANUP_TRAP_CACHES environment variable no longer has any effect",
+      );
+    await target.passes(t.is, undefined);
+    t.deepEqual(
+      target.getLogger().messages.map((m) => m.type),
+      ["warning"],
+    );
+  });
+}
+
+test("warnIfTrapCacheCleanupEnvVarIsSet doesn't warn when CODEQL_ACTION_CLEANUP_TRAP_CACHES is unset", async (t) => {
+  const target = callee(warnIfTrapCacheCleanupEnvVarIsSet).withArgs();
+  await target.passes(t.is, undefined);
+  t.deepEqual(target.getLogger().messages, []);
+});

src/trap-caching.ts

@@ -3,6 +3,7 @@ import * as path from "path";
 
 import * as actionsCache from "@actions/cache";
 
+import { type ActionState } from "./action-common";
 import * as actionsUtil from "./actions-util";
 import { type CodeQL } from "./codeql";
 import { type Config } from "./config-utils";
@@ -169,6 +170,25 @@ export async function uploadTrapCaches(
   return true;
 }
 
+/**
+ * Warns if the `CODEQL_ACTION_CLEANUP_TRAP_CACHES` environment variable is set to a non-empty
+ * value. That variable controlled the removed TRAP cache cleanup feature, so setting it has no
+ * effect.
+ */
+export function warnIfTrapCacheCleanupEnvVarIsSet({
+  env,
+  logger,
+}: ActionState<["Logger", "ReadOnlyEnv"]>): void {
+  if (env.getOptional("CODEQL_ACTION_CLEANUP_TRAP_CACHES") !== undefined) {
+    logger.warning(
+      "TRAP cache cleanup has been removed, so the CODEQL_ACTION_CLEANUP_TRAP_CACHES environment " +
+        "variable no longer has any effect and can be removed from your workflow. If you used TRAP " +
+        "cache cleanup to limit Actions cache usage, we recommend disabling TRAP caching instead by " +
+        "passing the `trap-caching: false` input to the `init` Action.",
+    );
+  }
+}
+
 export async function getLanguagesSupportingCaching(
   codeql: CodeQL,
   languages: Language[],