squash! Prefer installing version from `toolchain` directive

Avoid installing from `toolchain` if `GOTOOLCHAIN` is `local`, also
better regex for matching toolchain directive

__tests__/setup-go.test.ts

@@ -129,6 +129,9 @@ describe('setup-go', () => {
   });
 
   afterEach(() => {
+    // clear out env var set during 'run'
+    delete process.env[im.GOTOOLCHAIN_ENV_VAR];
+
     //jest.resetAllMocks();
     jest.clearAllMocks();
     //jest.restoreAllMocks();
@@ -989,11 +992,16 @@ use .
   });
 
   describe('go-version-file-toolchain', () => {
-    const goModContents = `module example.com/mymodule
+    const goVersions = ['1.22.0', '1.21rc2', '1.18'];
+    const placeholderVersion = '1.19';
+    const buildGoMod = (
+      goVersion: string,
+      toolchainVersion: string
+    ) => `module example.com/mymodule
 
-go 1.14
+go ${goVersion}
 
-toolchain go1.21.0
+toolchain go${toolchainVersion}
 
 require (
 	example.com/othermodule v1.2.3
@@ -1005,36 +1013,67 @@ replace example.com/thatmodule => ../thatmodule
 exclude example.com/thismodule v1.3.0
 `;
 
-    const goWorkContents = `go 1.19
+    const buildGoWork = (
+      goVersion: string,
+      toolchainVersion: string
+    ) => `go 1.19
 
-toolchain go1.21.0
+toolchain go${toolchainVersion}
 
 use .
 
 `;
 
-    it('reads version from toolchain directive in go.mod', async () => {
-      inputs['go-version-file'] = 'go.mod';
-      existsSpy.mockImplementation(() => true);
-      readFileSpy.mockImplementation(() => Buffer.from(goModContents));
-
-      await main.run();
-
-      expect(logSpy).toHaveBeenCalledWith('Setup go version spec 1.21.0');
-      expect(logSpy).toHaveBeenCalledWith('Attempting to download 1.21.0...');
-      expect(logSpy).toHaveBeenCalledWith('matching 1.21.0...');
-    });
-
-    it('reads version from toolchain directive in go.work', async () => {
-      inputs['go-version-file'] = 'go.work';
-      existsSpy.mockImplementation(() => true);
-      readFileSpy.mockImplementation(() => Buffer.from(goWorkContents));
-
-      await main.run();
-
-      expect(logSpy).toHaveBeenCalledWith('Setup go version spec 1.21.0');
-      expect(logSpy).toHaveBeenCalledWith('Attempting to download 1.21.0...');
-      expect(logSpy).toHaveBeenCalledWith('matching 1.21.0...');
+    goVersions.forEach(version => {
+      [
+        {
+          goVersionfile: 'go.mod',
+          fileContents: Buffer.from(buildGoMod(placeholderVersion, version)),
+          expected_version: version,
+          desc: 'from toolchain directive'
+        },
+        {
+          goVersionfile: 'go.work',
+          fileContents: Buffer.from(buildGoMod(placeholderVersion, version)),
+          expected_version: version,
+          desc: 'from toolchain directive'
+        },
+        {
+          goVersionfile: 'go.mod',
+          fileContents: Buffer.from(buildGoMod(placeholderVersion, version)),
+          gotoolchain_env: 'local',
+          expected_version: placeholderVersion,
+          desc: 'from go directive when GOTOOLCHAIN is local'
+        },
+        {
+          goVersionfile: 'go.work',
+          fileContents: Buffer.from(buildGoMod(placeholderVersion, version)),
+          gotoolchain_env: 'local',
+          expected_version: placeholderVersion,
+          desc: 'from go directive when GOTOOLCHAIN is local'
+        }
+      ].forEach(test => {
+        it(`reads version (${version}) in ${test.goVersionfile} ${test.desc}`, async () => {
+          inputs['go-version-file'] = test.goVersionfile;
+          if (test.gotoolchain_env !== undefined) {
+            process.env[im.GOTOOLCHAIN_ENV_VAR] = test.gotoolchain_env;
+          }
+          existsSpy.mockImplementation(() => true);
+          readFileSpy.mockImplementation(() => Buffer.from(test.fileContents));
+
+          await main.run();
+
+          expect(logSpy).toHaveBeenCalledWith(
+            `Setup go version spec ${test.expected_version}`
+          );
+          expect(logSpy).toHaveBeenCalledWith(
+            `Attempting to download ${test.expected_version}...`
+          );
+          expect(logSpy).toHaveBeenCalledWith(
+            `matching ${test.expected_version}...`
+          );
+        });
+      });
     });
   });
 

dist/setup/index.js

@@ -94666,10 +94666,14 @@ function parseGoVersionFile(versionFilePath) {
     const contents = fs_1.default.readFileSync(versionFilePath).toString();
     if (path.basename(versionFilePath) === 'go.mod' ||
         path.basename(versionFilePath) === 'go.work') {
-        // toolchain directive: https://go.dev/ref/mod#go-mod-file-toolchain
-        const matchToolchain = contents.match(/^toolchain go(\d+(\.\d+)*)/m);
-        if (matchToolchain) {
-            return matchToolchain[1];
+        // for backwards compatibility: use version from go directive if
+        // 'GOTOOLCHAIN' has been explicitly set
+        if (process.env[exports.GOTOOLCHAIN_ENV_VAR] !== exports.GOTOOLCHAIN_LOCAL_VAL) {
+            // toolchain directive: https://go.dev/ref/mod#go-mod-file-toolchain
+            const matchToolchain = contents.match(/^toolchain go(1\.\d+(?:\.\d+|rc\d+)?)/m);
+            if (matchToolchain) {
+                return matchToolchain[1];
+            }
         }
         // go directive: https://go.dev/ref/mod#go-mod-file-go
         const matchGo = contents.match(/^go (\d+(\.\d+)*)/m);

src/installer.ts

@@ -497,10 +497,16 @@ export function parseGoVersionFile(versionFilePath: string): string {
     path.basename(versionFilePath) === 'go.mod' ||
     path.basename(versionFilePath) === 'go.work'
   ) {
-    // toolchain directive: https://go.dev/ref/mod#go-mod-file-toolchain
-    const matchToolchain = contents.match(/^toolchain go(\d+(\.\d+)*)/m);
-    if (matchToolchain) {
-      return matchToolchain[1];
+    // for backwards compatibility: use version from go directive if
+    // 'GOTOOLCHAIN' has been explicitly set
+    if (process.env[GOTOOLCHAIN_ENV_VAR] !== GOTOOLCHAIN_LOCAL_VAL) {
+      // toolchain directive: https://go.dev/ref/mod#go-mod-file-toolchain
+      const matchToolchain = contents.match(
+        /^toolchain go(1\.\d+(?:\.\d+|rc\d+)?)/m
+      );
+      if (matchToolchain) {
+        return matchToolchain[1];
+      }
     }
 
     // go directive: https://go.dev/ref/mod#go-mod-file-go