Log unexpected conditions during caching CLI output

src/cli/output-cache.test.ts

@@ -4,6 +4,7 @@ import path from "path";
 import test from "ava";
 
 import { EnvVar } from "../environment";
+import { getRunnerLogger } from "../logging";
 import { getTestEnv, setupTests } from "../testing-utils";
 import * as util from "../util";
 
@@ -11,6 +12,8 @@ import * as outputCache from "./output-cache";
 
 setupTests(test);
 
+const logger = getRunnerLogger(true);
+
 test.serial(
   "getCachedCodeQlVersion reuses a version persisted by an earlier step",
   async (t) => {
@@ -25,9 +28,12 @@ test.serial(
         "utf8",
       );
       const env = getTestEnv({ [EnvVar.TEMP]: tmpDir });
-      t.deepEqual(outputCache.getCachedCodeQlVersion(env, "/path/to/codeql"), {
-        version: "2.20.0",
-      });
+      t.deepEqual(
+        outputCache.getCachedCodeQlVersion(logger, env, "/path/to/codeql"),
+        {
+          version: "2.20.0",
+        },
+      );
     });
   },
 );
@@ -47,7 +53,7 @@ test.serial(
       );
       const env = getTestEnv({ [EnvVar.TEMP]: tmpDir });
       t.is(
-        outputCache.getCachedCodeQlVersion(env, "/path/to/codeql"),
+        outputCache.getCachedCodeQlVersion(logger, env, "/path/to/codeql"),
         undefined,
       );
     });
@@ -62,7 +68,7 @@ test.serial(
       fs.writeFileSync(cacheFile, "not valid json", "utf8");
       const env = getTestEnv({ [EnvVar.TEMP]: tmpDir });
       t.is(
-        outputCache.getCachedCodeQlVersion(env, "/path/to/codeql"),
+        outputCache.getCachedCodeQlVersion(logger, env, "/path/to/codeql"),
         undefined,
       );
     });
@@ -100,7 +106,7 @@ test.serial(
       for (const value of testValues) {
         fs.writeFileSync(cacheFile, value, "utf8");
         t.is(
-          outputCache.getCachedCodeQlVersion(env, "/path/to/codeql"),
+          outputCache.getCachedCodeQlVersion(logger, env, "/path/to/codeql"),
           undefined,
           value,
         );
@@ -114,7 +120,7 @@ test.serial("getCachedCodeQlVersion ignores non-existent file", async (t) => {
     const env = getTestEnv({ [EnvVar.TEMP]: tmpDir });
     t.notThrows(() => {
       t.is(
-        outputCache.getCachedCodeQlVersion(env, "/path/to/codeql"),
+        outputCache.getCachedCodeQlVersion(logger, env, "/path/to/codeql"),
         undefined,
       );
     });

src/cli/output-cache.ts

@@ -3,6 +3,7 @@ import path from "path";
 
 import { getTemporaryDirectory } from "../actions-util";
 import { Env } from "../environment";
+import { Logger } from "../logging";
 
 import type { VersionInfo } from "./types";
 
@@ -78,10 +79,12 @@ export function cacheCodeQlVersion(
 
 /**
  * Returns the cached CodeQL CLI version, if any.
+ * @param logger The logger to use for logging messages.
  * @param env The environment variables to use.
  * @param cmd The path to the CodeQL CLI.
  */
 export function getCachedCodeQlVersion(
+  logger: Logger,
   env: Env,
   cmd?: string,
 ): undefined | VersionInfo {
@@ -94,13 +97,17 @@ export function getCachedCodeQlVersion(
   let serialized: string;
   try {
     serialized = fs.readFileSync(getCommandCacheFilePath(env), "utf8");
-  } catch {
+  } catch (e) {
+    logger.debug(
+      `Cannot read CLI-cache file ${getCommandCacheFilePath(env)}: ${e}`,
+    );
     return undefined;
   }
   let persisted: unknown;
   try {
     persisted = JSON.parse(serialized);
-  } catch {
+  } catch (e) {
+    logger.debug(`Cannot parse CLI-cache data as JSON: ${e}`);
     return undefined;
   }
   if (