Omit unknown HTTP status codes from download errors

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

src/tools-download.test.ts

@@ -1,9 +1,12 @@
 import { once } from "events";
 import * as fs from "fs";
+import { ClientRequest, IncomingMessage } from "http";
 import * as path from "path";
 
+import * as core from "@actions/core";
 import * as toolcache from "@actions/tool-cache";
 import test from "ava";
+import { https } from "follow-redirects";
 import nock from "nock";
 import * as sinon from "sinon";
 
@@ -158,6 +161,48 @@ test.serial(
   },
 );
 
+test.serial(
+  "downloadAndExtract omits an unknown HTTP status from the error message",
+  async (t) => {
+    await withTmpDir(async (tmpDir) => {
+      sinon.stub(process, "platform").value("linux");
+      const archivePath = path.join(tmpDir, "codeql-bundle.tar.zst");
+      const destination = path.join(tmpDir, "codeql");
+      const response = sinon.createStubInstance(IncomingMessage);
+      response.statusCode = undefined;
+      sinon
+        .stub(https, "get")
+        .callsArgWith(2, response)
+        .returns(sinon.createStubInstance(ClientRequest));
+      const warning = sinon.stub(core, "warning");
+      const downloadTool = sinon
+        .stub(toolcache, "downloadTool")
+        .resolves(archivePath);
+      const extract = sinon.stub(tar, "extract").resolves(destination);
+      const extractTarZst = sinon.stub(tar, "extractTarZst").resolves();
+
+      await downloadAndExtract(
+        "https://example.com/codeql-bundle.tar.zst",
+        "zstd",
+        destination,
+        undefined,
+        {},
+        { type: "gnu", version: "1.34" },
+        getRunnerLogger(true),
+      );
+
+      t.is(
+        warning.firstCall.args[0],
+        "Failed to download and extract CodeQL bundle using streaming with error: Failed to download CodeQL bundle from https://example.com/codeql-bundle.tar.zst.",
+      );
+      t.true(response.resume.calledOnce);
+      t.false(extractTarZst.called);
+      t.true(downloadTool.calledOnce);
+      t.true(extract.calledOnce);
+    });
+  },
+);
+
 test.serial(
   "downloadAndExtract reports only the total duration when streaming extraction",
   async (t) => {

src/tools-download.ts

@@ -200,13 +200,15 @@ async function downloadAndExtractZstdWithStreaming(
     });
   });
 
-  if (response.statusCode !== 200) {
+  const statusCode = response.statusCode ?? 0;
+  if (statusCode !== 200) {
     // Discard the response body so that the connection can be released.
     response.resume();
-    throw new HTTPError(
-      `Failed to download CodeQL bundle from ${codeqlURL}. HTTP status code: ${response.statusCode}.`,
-      response.statusCode ?? 0,
-    );
+    let message = `Failed to download CodeQL bundle from ${codeqlURL}.`;
+    if (statusCode !== 0) {
+      message += ` HTTP status code: ${statusCode}.`;
+    }
+    throw new HTTPError(message, statusCode);
   }
 
   await tar.extractTarZst(response, dest, tarVersion, logger);