fix(manager/gomod): perfer to use go version defined as toolchain to update artifacts

lib/modules/manager/gomod/artifacts.spec.ts

@@ -2,7 +2,7 @@ import { codeBlock } from 'common-tags';
 import { join } from 'upath';
 import { mockDeep } from 'vitest-mock-extended';
 import { envMock, mockExecAll } from '../../../../test/exec-util';
-import { env, fs, git, mocked, partial } from '../../../../test/util';
+import { env, fs, git, partial } from '../../../../test/util';
 import { GlobalConfig } from '../../../config/global';
 import type { RepoGlobalConfig } from '../../../config/types';
 import * as docker from '../../../util/exec/docker';
@@ -31,9 +31,9 @@ vi.mock('./artifacts-extra', () => mockDeep());
 
 process.env.CONTAINERBASE = 'true';
 
-const datasource = mocked(_datasource);
-const hostRules = mocked(_hostRules);
-const artifactsExtra = mocked(_artifactsExtra);
+const datasource = vi.mocked(_datasource);
+const hostRules = vi.mocked(_hostRules);
+const artifactsExtra = vi.mocked(_artifactsExtra);
 
 const gomod1 = codeBlock`
   module github.com/renovate-tests/gomod1
@@ -1820,7 +1820,6 @@ describe('modules/manager/gomod/artifacts', () => {
   it('updates import paths with specific tool version from constraint', async () => {
     fs.readLocalFile.mockResolvedValueOnce('Current go.sum');
     fs.readLocalFile.mockResolvedValueOnce(null); // vendor modules filename
-    fs.readLocalFile.mockResolvedValueOnce('go.mod file');
     const execSnapshots = mockExecAll();
     git.getRepoStatus.mockResolvedValueOnce(
       partial<StatusResult>({
@@ -1879,7 +1878,6 @@ describe('modules/manager/gomod/artifacts', () => {
   it('updates import paths with latest tool version on invalid version constraint', async () => {
     fs.readLocalFile.mockResolvedValueOnce('Current go.sum');
     fs.readLocalFile.mockResolvedValueOnce(null); // vendor modules filename
-    fs.readLocalFile.mockResolvedValueOnce('go.mod file');
     const execSnapshots = mockExecAll();
     git.getRepoStatus.mockResolvedValueOnce(
       partial<StatusResult>({
@@ -1997,7 +1995,6 @@ describe('modules/manager/gomod/artifacts', () => {
     GlobalConfig.set({ ...adminConfig, binarySource: 'install' });
     fs.readLocalFile.mockResolvedValueOnce('Current go.sum');
     fs.readLocalFile.mockResolvedValueOnce(null); // vendor modules filename
-    fs.readLocalFile.mockResolvedValueOnce(null);
     const execSnapshots = mockExecAll();
     git.getRepoStatus.mockResolvedValueOnce(
       partial<StatusResult>({
@@ -2056,7 +2053,6 @@ describe('modules/manager/gomod/artifacts', () => {
     GlobalConfig.set({ ...adminConfig, binarySource: 'docker' });
     fs.readLocalFile.mockResolvedValueOnce('Current go.sum');
     fs.readLocalFile.mockResolvedValueOnce(null); // vendor modules filename
-    fs.readLocalFile.mockResolvedValueOnce('someText\n\ngo 1.17\n\n');
     const execSnapshots = mockExecAll();
     git.getRepoStatus.mockResolvedValueOnce(
       partial<StatusResult>({
@@ -2075,7 +2071,7 @@ describe('modules/manager/gomod/artifacts', () => {
       updatedDeps: [
         { depName: 'github.com/google/go-github/v24', newVersion: 'v28.0.0' },
       ],
-      newPackageFileContent: gomod1,
+      newPackageFileContent: 'someText\n\ngo 1.17\n\n' + gomod1,
       config: {
         updateType: 'major',
         postUpdateOptions: ['gomodUpdateImportPaths'],
@@ -2125,12 +2121,56 @@ describe('modules/manager/gomod/artifacts', () => {
     expect(execSnapshots).toMatchObject(expectedResult);
   });
 
+  it('go.mod file contains go toolchain version', async () => {
+    GlobalConfig.set({ ...adminConfig, binarySource: 'install' });
+    fs.readLocalFile.mockResolvedValueOnce('Current go.sum');
+    fs.readLocalFile.mockResolvedValueOnce(null); // vendor modules filename
+    const execSnapshots = mockExecAll();
+    git.getRepoStatus.mockResolvedValueOnce(
+      partial<StatusResult>({
+        modified: ['go.sum'],
+      }),
+    );
+    fs.readLocalFile
+      .mockResolvedValueOnce('New go.sum')
+      .mockResolvedValueOnce('New go.mod');
+    datasource.getPkgReleases.mockResolvedValueOnce({
+      releases: [
+        { version: '1.17.0' },
+        { version: '1.23.6' },
+        { version: '1.24.0' },
+      ],
+    });
+    const res = await gomod.updateArtifacts({
+      packageFileName: 'go.mod',
+      updatedDeps: [{ depName: 'golang.org/x/crypto', newVersion: '0.35.0' }],
+      newPackageFileContent:
+        'someText\n\ngo 1.13\n\ntoolchain go1.23.6\n\n' + gomod1,
+      config: {
+        updateType: 'minor',
+      },
+    });
+
+    expect(res).toEqual([
+      { file: { type: 'addition', path: 'go.sum', contents: 'New go.sum' } },
+      { file: { type: 'addition', path: 'go.mod', contents: 'New go.mod' } },
+    ]);
+
+    expect(execSnapshots).toMatchObject([
+      {
+        cmd: 'install-tool golang 1.23.6',
+      },
+      {
+        cmd: 'go get -d -t ./...',
+      },
+    ]);
+  });
+
   it('returns artifact notices', async () => {
     artifactsExtra.getExtraDepsNotice.mockReturnValue('some extra notice');
     GlobalConfig.set({ ...adminConfig, binarySource: 'docker' });
     fs.readLocalFile.mockResolvedValueOnce('Current go.sum');
     fs.readLocalFile.mockResolvedValueOnce(null); // vendor modules filename
-    fs.readLocalFile.mockResolvedValueOnce('someText\n\ngo 1.17\n\n');
     mockExecAll();
     git.getRepoStatus.mockResolvedValueOnce(
       partial<StatusResult>({
@@ -2149,7 +2189,7 @@ describe('modules/manager/gomod/artifacts', () => {
       updatedDeps: [
         { depName: 'github.com/google/go-github/v24', newVersion: 'v28.0.0' },
       ],
-      newPackageFileContent: gomod1,
+      newPackageFileContent: 'someText\n\ngo 1.17\n\n' + gomod1,
       config: {
         updateType: 'major',
         postUpdateOptions: ['gomodUpdateImportPaths'],

lib/modules/manager/gomod/artifacts.ts

@@ -191,7 +191,7 @@ export async function updateArtifacts({
     }
   }
   const goConstraints =
-    config.constraints?.go ?? (await getGoConstraints(goModFileName));
+    config.constraints?.go ?? getGoConstraints(massagedGoMod);
 
   try {
     await writeLocalFile(goModFileName, massagedGoMod);
@@ -444,15 +444,16 @@ export async function updateArtifacts({
   }
 }
 
-async function getGoConstraints(
-  goModFileName: string,
-): Promise<string | undefined> {
-  const content = (await readLocalFile(goModFileName, 'utf8')) ?? null;
-  if (!content) {
-    return undefined;
+function getGoConstraints(goModContent: string): string | undefined {
+  // prefer toolchain directive when go.mod has one
+  const toolchain = regEx(/^toolchain\s*go(?<gover>\d+\.\d+\.\d+)$/m);
+  const toolchainMatch = toolchain.exec(goModContent);
+  if (toolchainMatch?.groups?.gover) {
+    return toolchainMatch.groups.gover;
   }
+
   const re = regEx(/^go\s*(?<gover>\d+\.\d+)$/m);
-  const match = re.exec(content);
+  const match = re.exec(goModContent);
   if (!match?.groups?.gover) {
     return undefined;
   }