Backport bugfixes from golangci-lint v2.13.2

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## v1.27.1 (unreleased)
+
+### Bug Fixes (backported)
+
+- **cache**: Reuse cached results across module locations ([golangci-lint#6762](https://github.com/golangci/golangci-lint/pull/6762)). Cache keys and cached issue positions embedded absolute paths, so a module checked out at a different path — CI runners, containers, renamed worktrees — never hit the cache. Paths are now stored relative to the module directory. This release invalidates existing cache entries once.
+- **staticcheck**: Fix two SA4023 false positives introduced in v1.27.0 ([v0.8.1](https://github.com/dominikh/go-tools/releases/tag/v0.8.1)). Unconstrained generics are no longer treated as never-nil ([#1736](https://github.com/dominikh/go-tools/issues/1736)), and comparisons not involving typed nils are no longer flagged ([#1737](https://github.com/dominikh/go-tools/issues/1737)) — `errors.New("") == nil` and similar defensive checks.
+- **unparam**: Fix panic on type parameters used by closures ([mvdan/unparam#2fa3d84](https://github.com/mvdan/unparam/commit/2fa3d841b0c8)). Packages that previously crashed now lint normally, so new findings may appear in generic code. Parameters of zero-sized generic types with phantom type parameters are no longer reported, matching `unparam`'s zero-size skip rule.
+
 ## v1.27.0 (2026-08-20)
 
 Rebased onto `golangci-lint` v2.13.1, targeting Go 1.27. This pulls forward everything from

go.mod

@@ -154,9 +154,9 @@ require (
 	golang.org/x/sync v0.22.0
 	golang.org/x/sys v0.47.0
 	golang.org/x/tools v0.49.0
-	honnef.co/go/tools v0.8.0
+	honnef.co/go/tools v0.8.1
 	mvdan.cc/gofumpt v0.11.0
-	mvdan.cc/unparam v0.0.0-20260818115549-3f964bcb5673
+	mvdan.cc/unparam v0.0.0-20260823230713-2fa3d841b0c8
 )
 
 require (

internal/cache/cache.go

@@ -172,6 +172,10 @@ func (c *Cache) computePkgHash(pkg *packages.Package) (hashResults, error) {
 			return nil, fmt.Errorf("failed to calculate file %s hash: %w", f, fErr)
 		}
 
+		if rel, ok := toRelativePath(pkg.Module, f); ok {
+			f = pkg.Module.Path + "/" + rel
+		}
+
 		fmt.Fprintf(key, "file %s %x\n", f, h)
 	}
 

internal/cache/position.go

@@ -0,0 +1,54 @@
+package cache
+
+import (
+	"go/token"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/tools/go/packages"
+)
+
+// RelativePosition creates a [token.Position] with a filename relative to the module directory.
+func RelativePosition(mod *packages.Module, pos token.Position) token.Position {
+	pos.Filename, _ = toRelativePath(mod, pos.Filename)
+
+	return pos
+}
+
+// AbsolutionPosition creates the absolute path base on the module directory.
+func AbsolutionPosition(mod *packages.Module, pos token.Position) token.Position {
+	pos.Filename = toAbsolutePath(mod, pos.Filename)
+
+	return pos
+}
+
+func toRelativePath(mod *packages.Module, filename string) (string, bool) {
+	if filename == "" || !isCurrentModule(mod) {
+		return filename, false
+	}
+
+	rel, err := filepath.Rel(mod.Dir, filename)
+	if err != nil {
+		return filename, false
+	}
+
+	rel = filepath.ToSlash(rel)
+
+	if rel == ".." || strings.HasPrefix(rel, "../") {
+		return filename, false
+	}
+
+	return rel, true
+}
+
+func toAbsolutePath(mod *packages.Module, filename string) string {
+	if filename == "" || !isCurrentModule(mod) || filepath.IsAbs(filename) {
+		return filename
+	}
+
+	return filepath.Join(mod.Dir, filepath.FromSlash(filename))
+}
+
+func isCurrentModule(mod *packages.Module) bool {
+	return mod != nil && mod.Dir != "" && mod.Version == ""
+}

internal/cache/position_test.go

@@ -0,0 +1,54 @@
+package cache
+
+import (
+	"go/token"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/tools/go/packages"
+)
+
+func TestRelativePosition(t *testing.T) {
+	mod := &packages.Module{Dir: "/my/path"}
+
+	initialPos := token.Position{
+		Filename: filepath.FromSlash("/my/path/foo.go"),
+		Offset:   1,
+		Line:     2,
+		Column:   3,
+	}
+
+	pos := RelativePosition(mod, initialPos)
+
+	expected := token.Position{
+		Filename: "foo.go",
+		Offset:   1,
+		Line:     2,
+		Column:   3,
+	}
+
+	assert.Equal(t, expected, pos)
+}
+
+func TestAbsolutionPosition(t *testing.T) {
+	mod := &packages.Module{Dir: "/my/other/path"}
+
+	initialPos := token.Position{
+		Filename: "foo.go",
+		Offset:   1,
+		Line:     2,
+		Column:   3,
+	}
+
+	pos := AbsolutionPosition(mod, initialPos)
+
+	expected := token.Position{
+		Filename: filepath.FromSlash("/my/other/path/foo.go"),
+		Offset:   1,
+		Line:     2,
+		Column:   3,
+	}
+
+	assert.Equal(t, expected, pos)
+}

pkg/commands/run.go

@@ -640,6 +640,7 @@ func initHashSalt(logger logutils.Log, version string, cfg *config.Config) error
 	}
 
 	b := bytes.NewBuffer(binSalt)
+	b.WriteString("golangci-lint-cache/v2")
 	b.Write(configSalt)
 	b.WriteString(goModSalt)
 
@@ -712,7 +713,8 @@ func computeGoModSalt() (string, error) {
 		return "", fmt.Errorf("failed to read go.mod: %w", err)
 	}
 
-	sum, err := dirhash.Hash1([]string{goModPath}, func(string) (io.ReadCloser, error) {
+	// NOTE: the variable `goModPath` is not used here to ensure getting the same hash, independently of the location, for the same content.
+	sum, err := dirhash.Hash1([]string{"go.mod"}, func(string) (io.ReadCloser, error) {
 		return io.NopCloser(bytes.NewReader(data)), nil
 	})
 	if err != nil {

pkg/goanalysis/runners_cache.go

@@ -42,7 +42,7 @@ func saveIssuesToCache(allPkgs []*packages.Package, pkgsFromCache map[*packages.
 						FromLinter:           issue.FromLinter,
 						Text:                 issue.Text,
 						Severity:             issue.Severity,
-						Pos:                  issue.Pos,
+						Pos:                  cache.RelativePosition(pkg.Module, issue.Pos),
 						LineRange:            issue.LineRange,
 						SuggestedFixes:       issue.SuggestedFixes,
 						ExpectNoLint:         issue.ExpectNoLint,
@@ -114,7 +114,7 @@ func loadIssuesFromCache(pkgs []*packages.Package, lintCtx *linter.Context,
 						FromLinter:           issue.FromLinter,
 						Text:                 issue.Text,
 						Severity:             issue.Severity,
-						Pos:                  issue.Pos,
+						Pos:                  cache.AbsolutionPosition(pkg.Module, issue.Pos),
 						LineRange:            issue.LineRange,
 						SuggestedFixes:       issue.SuggestedFixes,
 						Pkg:                  pkg,