Add support for native Go version syntax in go-version input (#804)

* Add support for native Go version syntax in go-version input

* Enhance Go-native version handling and update tests and documentation

* Update docs

src/installer.ts

@@ -60,6 +60,11 @@ export async function getGo(
   const osPlat: string = os.platform();
   const customBaseUrl = goDownloadBaseUrl?.replace(/\/+$/, '');
 
+  const originalVersionSpec = versionSpec;
+  if (isGoNativeVersion(versionSpec)) {
+    versionSpec = makeSemver(versionSpec);
+  }
+
   if (
     versionSpec === StableReleaseAlias.Stable ||
     versionSpec === StableReleaseAlias.OldStable
@@ -146,7 +151,11 @@ export async function getGo(
       core.info(
         'Skipping version listing for known direct-download URL. Constructing download URL directly.'
       );
-      info = getInfoFromDirectDownload(versionSpec, arch, customBaseUrl);
+      info = getInfoFromDirectDownload(
+        originalVersionSpec,
+        arch,
+        customBaseUrl
+      );
     } else {
       try {
         info = await getInfoFromDist(versionSpec, arch, customBaseUrl);
@@ -156,7 +165,11 @@ export async function getGo(
         );
       }
       if (!info) {
-        info = getInfoFromDirectDownload(versionSpec, arch, customBaseUrl);
+        info = getInfoFromDirectDownload(
+          originalVersionSpec,
+          arch,
+          customBaseUrl
+        );
       }
     }
 
@@ -167,13 +180,13 @@ export async function getGo(
       const downloadUrl = info?.downloadUrl || customBaseUrl;
       if (err instanceof tc.HTTPError && err.httpStatusCode === 404) {
         throw new Error(
-          `The requested Go version ${versionSpec} is not available for platform ${osPlat}/${arch}. ` +
+          `The requested Go version ${originalVersionSpec} is not available for platform ${osPlat}/${arch}. ` +
             `Download URL returned HTTP 404: ${downloadUrl}`,
           {cause: err}
         );
       }
       throw new Error(
-        `Failed to download Go ${versionSpec} for platform ${osPlat}/${arch} ` +
+        `Failed to download Go ${originalVersionSpec} for platform ${osPlat}/${arch} ` +
           `from ${downloadUrl}: ${err}`,
         {cause: err}
       );
@@ -610,6 +623,12 @@ export async function findMatch(
   return result;
 }
 
+export function isGoNativeVersion(version: string): boolean {
+  const expression =
+    /^go[1-9]\d*\.(0|[1-9]\d*)(?:\.(0|[1-9]\d*)|(?:beta|rc)[1-9]\d*)?$/;
+  return expression.test(version);
+}
+
 //
 // Convert the go version syntax into semver for semver matching
 // 1.13.1 => 1.13.1
@@ -617,6 +636,10 @@ export async function findMatch(
 // 1.10beta1 => 1.10.0-beta.1, 1.10rc1 => 1.10.0-rc.1
 // 1.8.5beta1 => 1.8.5-beta.1, 1.8.5rc1 => 1.8.5-rc.1
 export function makeSemver(version: string): string {
+  const validVersion = semver.valid(version);
+  if (validVersion) {
+    return validVersion;
+  }
   version = version.replace('go', '');
   version = version.replace('beta', '-beta.').replace('rc', '-rc.');
   const parts = version.split('-');

src/main.ts

@@ -215,6 +215,18 @@ function resolveVersionInput(): string {
   }
 
   if (version) {
+    const customBaseUrl =
+      core.getInput('go-download-base-url') ||
+      process.env['GO_DOWNLOAD_BASE_URL'];
+    if (
+      version.startsWith('go') &&
+      !customBaseUrl &&
+      !installer.isGoNativeVersion(version)
+    ) {
+      throw new Error(
+        `Invalid Go version "${version}". Go-native versions must look like go1.21, go1.21.5, go1.18beta2, or go1.21rc2. For version ranges, use SemVer syntax (e.g. ~1.21, ^1.21).`
+      );
+    }
     return version;
   }