Add option to skip Astral mirror downloads (#387)

## Summary
- add `download-from-astral-mirror` input defaulting to `true`
- skip mirror URL rewriting and download directly from GitHub Releases
when disabled
- document the input and add unit coverage

Fixes #384

Refs: pi-session 019f31bc-bd1c-7276-9b4e-9734fa0aa367

## Testing
- npm run build
- npm run check
- npm run test:unit

src/download/download-version.ts

@@ -35,6 +35,7 @@ export async function downloadVersion(
   checksum: string | undefined,
   githubToken: string,
   manifestUrl?: string,
+  downloadFromAstralMirror = true,
 ): Promise<{ version: string; cachedToolDir: string }> {
   const artifact = await getArtifact(version, arch, platform, manifestUrl);
 
@@ -57,6 +58,7 @@ export async function downloadVersion(
     arch,
     version,
     getDownloadToken(artifact.downloadUrl, githubToken),
+    downloadFromAstralMirror,
   );
   await validateChecksum(
     resolvedChecksum,
@@ -83,6 +85,10 @@ export async function downloadVersion(
   return { cachedToolDir, version };
 }
 
+/**
+ * Rewrite a GitHub Releases URL to the Astral mirror.
+ * Returns `undefined` if the URL does not match the expected GitHub prefix.
+ */
 export function rewriteToMirror(url: string): string | undefined {
   if (!url.startsWith(GITHUB_RELEASES_PREFIX)) {
     return undefined;
@@ -97,8 +103,11 @@ async function downloadArtifact(
   arch: Architecture,
   version: string,
   githubToken: string | undefined,
+  downloadFromAstralMirror: boolean,
 ): Promise<string> {
-  const mirrorUrl = rewriteToMirror(downloadUrl);
+  const mirrorUrl = downloadFromAstralMirror
+    ? rewriteToMirror(downloadUrl)
+    : undefined;
   const resolvedDownloadUrl = mirrorUrl ?? downloadUrl;
 
   try {

src/ruff-action.ts

@@ -9,6 +9,7 @@ import {
 import {
   args,
   checkSum,
+  downloadFromAstralMirror,
   githubToken,
   manifestFile,
   src,
@@ -39,7 +40,13 @@ async function run(): Promise<void> {
     if (arch === undefined) {
       throw new Error(`Unsupported architecture: ${process.arch}`);
     }
-    const setupResult = await setupRuff(platform, arch, checkSum, githubToken);
+    const setupResult = await setupRuff(
+      platform,
+      arch,
+      checkSum,
+      githubToken,
+      downloadFromAstralMirror,
+    );
 
     addRuffToPath(setupResult.ruffDir);
     setOutputFormat();
@@ -60,6 +67,7 @@ async function setupRuff(
   arch: Architecture,
   checkSum: string | undefined,
   githubToken: string,
+  downloadFromAstralMirror: boolean,
 ): Promise<{ ruffDir: string; version: string }> {
   const resolvedVersion = await determineVersion();
   const manifestUrl = manifestFile || undefined;
@@ -84,6 +92,7 @@ async function setupRuff(
     checkSum,
     githubToken,
     manifestUrl,
+    downloadFromAstralMirror,
   );
 
   return {

src/utils/inputs.ts

@@ -7,3 +7,14 @@ export const args = core.getInput("args");
 export const src = core.getInput("src");
 export const versionFile = core.getInput("version-file");
 export const manifestFile = core.getInput("manifest-file");
+export const downloadFromAstralMirror = getBooleanInput(
+  "download-from-astral-mirror",
+  true,
+);
+
+function getBooleanInput(name: string, defaultValue: boolean): boolean {
+  if (core.getInput(name) === "") {
+    return defaultValue;
+  }
+  return core.getBooleanInput(name);
+}