disable automatic toolchain switching for golang hooks

pre_commit/languages/golang.py

@@ -75,6 +75,7 @@ def get_env_patch(venv: str, version: str) -> PatchesT:
 
     return (
         ('GOROOT', os.path.join(venv, '.go')),
+        ('GOTOOLCHAIN', 'local'),
         (
             'PATH', (
                 os.path.join(venv, 'bin'), os.pathsep,
@@ -145,6 +146,7 @@ def install_environment(
     env = no_git_env(dict(os.environ, GOPATH=gopath))
     env.pop('GOBIN', None)
     if version != 'system':
+        env['GOTOOLCHAIN'] = 'local'
         env['GOROOT'] = os.path.join(env_dir, '.go')
         env['PATH'] = os.pathsep.join((
             os.path.join(env_dir, '.go', 'bin'), os.environ['PATH'],

tests/languages/golang_test.py

@@ -11,11 +11,13 @@ from pre_commit.commands.install_uninstall import install
 from pre_commit.envcontext import envcontext
 from pre_commit.languages import golang
 from pre_commit.store import _make_local_repo
+from pre_commit.util import CalledProcessError
 from pre_commit.util import cmd_output
 from testing.fixtures import add_config_to_repo
 from testing.fixtures import make_config_from_repo
 from testing.language_helpers import run_language
 from testing.util import cmd_output_mocked_pre_commit_home
+from testing.util import cwd
 from testing.util import git_commit
 
 
@@ -165,3 +167,70 @@ def test_during_commit_all(tmp_path, tempdir_factory, store, in_git_dir):
         fn=cmd_output_mocked_pre_commit_home,
         tempdir_factory=tempdir_factory,
     )
+
+
+def test_automatic_toolchain_switching(tmp_path):
+    go_mod = '''\
+module toolchain-version-test
+
+go 1.23.1
+'''
+    main_go = '''\
+package main
+
+func main() {}
+'''
+    tmp_path.joinpath('go.mod').write_text(go_mod)
+    mod_dir = tmp_path.joinpath('toolchain-version-test')
+    mod_dir.mkdir()
+    main_file = mod_dir.joinpath('main.go')
+    main_file.write_text(main_go)
+
+    with pytest.raises(CalledProcessError) as excinfo:
+        run_language(
+            path=tmp_path,
+            language=golang,
+            version='1.22.0',
+            exe='golang-version-test',
+        )
+
+    assert 'go.mod requires go >= 1.23.1' in excinfo.value.stderr.decode()
+
+
+def test_automatic_toolchain_switching_go_fmt(tmp_path, monkeypatch):
+    go_mod_hook = '''\
+module toolchain-version-test
+
+go 1.22.0
+'''
+    go_mod = '''\
+module toolchain-version-test
+
+go 1.23.1
+'''
+    main_go = '''\
+package main
+
+func main() {}
+'''
+    hook_dir = tmp_path.joinpath('hook')
+    hook_dir.mkdir()
+    hook_dir.joinpath('go.mod').write_text(go_mod_hook)
+
+    test_dir = tmp_path.joinpath('test')
+    test_dir.mkdir()
+    test_dir.joinpath('go.mod').write_text(go_mod)
+    main_file = test_dir.joinpath('main.go')
+    main_file.write_text(main_go)
+
+    with cwd(test_dir):
+        ret, out = run_language(
+            path=hook_dir,
+            language=golang,
+            version='1.22.0',
+            exe='go fmt',
+            file_args=(str(main_file),),
+        )
+
+        assert ret == 1
+        assert 'go.mod requires go >= 1.23.1' in out.decode()