golangci-lint custom follows plugin's go.mod replace directives

pkg/commands/internal/builder.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/sha256"
 	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"io"
 	"os"
@@ -115,6 +116,11 @@ func (b Builder) addToGoMod(ctx context.Context) error {
 				return err
 			}
 
+			err = b.mergeReplaceDirectives(ctx, plugin.Path)
+			if err != nil {
+				return err
+			}
+
 			continue
 		}
 
@@ -162,6 +168,89 @@ func (b Builder) addReplaceDirective(ctx context.Context, plugin *Plugin) error
 	return nil
 }
 
+type goModReplace struct {
+	Replace []struct {
+		Old struct{ Path, Version string }
+		New struct{ Path, Version string }
+	}
+}
+
+func readGoModReplace(ctx context.Context, dir string) (*goModReplace, error) {
+	cmd := exec.CommandContext(ctx, "go", "mod", "edit", "-json")
+	cmd.Dir = dir
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", strings.Join(cmd.Args, " "), err)
+	}
+
+	var goMod goModReplace
+	err = json.Unmarshal(output, &goMod)
+	if err != nil {
+		return nil, fmt.Errorf("unmarshal go.mod json: %w", err)
+	}
+
+	return &goMod, nil
+}
+
+func (b Builder) mergeReplaceDirectives(ctx context.Context, pluginPath string) error {
+	pluginGoMod, err := readGoModReplace(ctx, pluginPath)
+	if err != nil {
+		return err
+	}
+
+	rootGoMod, err := readGoModReplace(ctx, b.repo)
+	if err != nil {
+		return err
+	}
+
+	for _, r := range pluginGoMod.Replace {
+		for _, rr := range rootGoMod.Replace {
+			if r.Old.Path == rr.Old.Path && r.Old.Version == rr.Old.Version {
+				return fmt.Errorf("duplicate replace directive for %s@%s", r.Old.Path, r.Old.Version)
+			}
+		}
+	}
+
+	for _, r := range pluginGoMod.Replace {
+		abs, err := filepath.Abs(filepath.Join(pluginPath, r.New.Path))
+		if err != nil {
+			return fmt.Errorf("get absolute path: %w", err)
+		}
+
+		stat, err := os.Stat(abs)
+		if err != nil {
+			return fmt.Errorf("%s: %w", abs, err)
+		}
+		if stat.IsDir() {
+			r.New.Path = abs
+		}
+
+		replace := fmt.Sprintf("%s=%s", r.Old.Path, r.New.Path)
+		if r.Old.Version != "" {
+			replace += "@" + r.Old.Version
+		}
+		if r.New.Version != "" {
+			replace += "@" + r.New.Version
+		}
+
+		cmd := exec.CommandContext(ctx, "go", "mod", "edit", "-replace", replace)
+		cmd.Dir = b.repo
+
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			b.log.Warnf("%s", string(output))
+
+			return fmt.Errorf("%s: %w", strings.Join(cmd.Args, " "), err)
+		}
+	}
+
+	// NOTE(sublee): We don't need to follow nested replace directives because
+	// the directives are effective only at the main module. All necessary
+	// replacements should be handled at this level.
+	return nil
+}
+
 func (b Builder) goModTidy(ctx context.Context) error {
 	cmd := exec.CommandContext(ctx, "go", "mod", "tidy")
 	cmd.Dir = b.repo

pkg/commands/internal/builder_test.go

@@ -1,9 +1,14 @@
 package internal
 
 import (
+	"encoding/json"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func Test_sanitizeVersion(t *testing.T) {
@@ -54,3 +59,107 @@ func Test_sanitizeVersion(t *testing.T) {
 		})
 	}
 }
+
+func TestMergeReplaceDirectives(t *testing.T) {
+	t.Parallel()
+
+	// Create a temporary module with the following structure:
+	// tmp/
+	//   go.mod
+	//   golangci-lint/
+	tmp := t.TempDir()
+	require.NoError(t, os.WriteFile(filepath.Join(tmp, "go.mod"), []byte(`
+module github.com/golangci/golangci-lint/v2
+go 1.24.0
+`), 0o600))
+	require.NoError(t, os.Mkdir(filepath.Join(tmp, "golangci-lint"), 0o700))
+
+	b := NewBuilder(nil, &Configuration{Plugins: []*Plugin{
+		{Module: "example.com/plugin", Path: "testdata/plugin"},
+	}}, tmp)
+
+	// Merge replace directives from the plugin's go.mod into the temporary
+	// repo. Only the plugin's own replace rules are applied; transitive
+	// replaces from its dependencies are not automatically merged.
+	err := b.mergeReplaceDirectives(t.Context(), filepath.Join("testdata", "plugin"))
+	require.NoError(t, err)
+
+	cmd := exec.CommandContext(t.Context(), "go", "mod", "edit", "-json")
+	cmd.Dir = b.repo
+	output, err := cmd.CombinedOutput()
+	require.NoError(t, err)
+
+	var goMod struct {
+		Replace []struct{ New struct{ Path string } }
+	}
+	err = json.Unmarshal(output, &goMod)
+	require.NoError(t, err)
+
+	// The go.mod file should include a replace directive for
+	// example.com/target, pointing to the local path, because
+	// example.com/plugin's go.mod defines it. However, it should not include a
+	// replace directive for example.com/other, since example.com/plugin does
+	// not directly depend on it, and go mod ignores such transitive
+	// replacements.
+	require.Len(t, goMod.Replace, 1)
+	assert.Contains(t, goMod.Replace[0].New.Path, "testdata/plugin/target")
+}
+
+func TestMergeReplaceDirectives_DuplicateReplace(t *testing.T) {
+	t.Parallel()
+
+	tmp := t.TempDir()
+	require.NoError(t, os.WriteFile(filepath.Join(tmp, "go.mod"), []byte(`
+module github.com/golangci/golangci-lint/v2
+go 1.24.0
+`), 0o600))
+	require.NoError(t, os.Mkdir(filepath.Join(tmp, "golangci-lint"), 0o700))
+
+	// Both plugins define a replace directive for example.com/target.
+	b := NewBuilder(nil, &Configuration{Plugins: []*Plugin{
+		{Module: "example.com/plugin", Path: "testdata/plugin"},
+		{Module: "example.com/plugin2", Path: "testdata/plugin2"},
+	}}, tmp)
+
+	err := b.mergeReplaceDirectives(t.Context(), filepath.Join("testdata", "plugin"))
+	require.NoError(t, err)
+
+	err = b.mergeReplaceDirectives(t.Context(), filepath.Join("testdata", "plugin2"))
+	assert.ErrorContains(t, err, "duplicate replace directive for example.com/target")
+}
+
+func TestMergeReplaceDirectives_DuplicateButDifferentVersion(t *testing.T) {
+	t.Parallel()
+
+	tmp := t.TempDir()
+	require.NoError(t, os.WriteFile(filepath.Join(tmp, "go.mod"), []byte(`
+module github.com/golangci/golangci-lint/v2
+go 1.24.0
+`), 0o600))
+	require.NoError(t, os.Mkdir(filepath.Join(tmp, "golangci-lint"), 0o700))
+
+	// Both plugins define a replace directive for example.com/target.
+	b := NewBuilder(nil, &Configuration{Plugins: []*Plugin{
+		{Module: "example.com/plugin", Path: "testdata/plugin"},
+		{Module: "example.com/plugin3", Path: "testdata/plugin3"},
+	}}, tmp)
+
+	err := b.mergeReplaceDirectives(t.Context(), filepath.Join("testdata", "plugin"))
+	require.NoError(t, err)
+
+	err = b.mergeReplaceDirectives(t.Context(), filepath.Join("testdata", "plugin3"))
+	require.NoError(t, err)
+
+	cmd := exec.CommandContext(t.Context(), "go", "mod", "edit", "-json")
+	cmd.Dir = b.repo
+	output, err := cmd.CombinedOutput()
+	require.NoError(t, err)
+
+	var goMod struct {
+		Replace []struct{ New struct{ Path string } }
+	}
+	err = json.Unmarshal(output, &goMod)
+	require.NoError(t, err)
+
+	assert.Len(t, goMod.Replace, 2)
+}

pkg/commands/internal/testdata/plugin/go.mod

@@ -0,0 +1,7 @@
+module example.com/plugin
+
+go 1.24.0
+
+require example.com/target v0.0.0
+
+replace example.com/target => ./target

pkg/commands/internal/testdata/plugin/plugin.go

@@ -0,0 +1,3 @@
+package plugin
+
+import _ "example.com/target"

pkg/commands/internal/testdata/plugin/target/go.mod

@@ -0,0 +1,7 @@
+module example.com/target
+
+go 1.24.0
+
+require example.com/other v0.0.0
+
+replace example.com/other => ./other

pkg/commands/internal/testdata/plugin/target/other/go.mod

@@ -0,0 +1,3 @@
+module example.com/other
+
+go 1.24.0

pkg/commands/internal/testdata/plugin/target/other/other.go

@@ -0,0 +1 @@
+package other

pkg/commands/internal/testdata/plugin/target/target.go

@@ -0,0 +1,3 @@
+package target
+
+import _ "example.com/other"

pkg/commands/internal/testdata/plugin2/go.mod

@@ -0,0 +1,7 @@
+module example.com/plugin2
+
+go 1.24.0
+
+require example.com/target v0.0.0
+
+replace example.com/target => ./target

pkg/commands/internal/testdata/plugin2/plugin.go

@@ -0,0 +1,3 @@
+package plugin
+
+import _ "example.com/target"

pkg/commands/internal/testdata/plugin2/target/go.mod

@@ -0,0 +1,3 @@
+module example.com/target
+
+go 1.24.0

pkg/commands/internal/testdata/plugin2/target/target.go

@@ -0,0 +1 @@
+package target

pkg/commands/internal/testdata/plugin3/go.mod

@@ -0,0 +1,7 @@
+module example.com/plugin2
+
+go 1.24.0
+
+require example.com/target v1.0.0
+
+replace example.com/[email protected] => ./target

pkg/commands/internal/testdata/plugin3/plugin.go

@@ -0,0 +1,3 @@
+package plugin
+
+import _ "example.com/target"

pkg/commands/internal/testdata/plugin3/target/go.mod

@@ -0,0 +1,3 @@
+module example.com/target
+
+go 1.24.0

pkg/commands/internal/testdata/plugin3/target/target.go

@@ -0,0 +1 @@
+package target