From 7032ec06267fcc5323ab7ad1fc84131120ec11cb Mon Sep 17 00:00:00 2001
From: Valentin Kiselev <mrexox@evilmartians.com>
Date: Thu, 20 Jun 2024 10:55:52 +0300
Subject: [PATCH] fix: apply local extends only if they are present

---
 internal/config/load.go      | 26 +++++++++++-----
 internal/config/load_test.go | 58 ++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 7 deletions(-)

diff --git a/internal/config/load.go b/internal/config/load.go
index 7c1f060d..9ce9f2e0 100644
--- a/internal/config/load.go
+++ b/internal/config/load.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"strings"
 
 	"github.com/spf13/afero"
@@ -20,7 +21,10 @@ const (
 	DefaultSourceDirLocal = ".lefthook-local"
 )
 
-var hookKeyRegexp = regexp.MustCompile(`^(?P<hookName>[^.]+)\.(scripts|commands)`)
+var (
+	hookKeyRegexp    = regexp.MustCompile(`^(?P<hookName>[^.]+)\.(scripts|commands)`)
+	localConfigNames = []string{"lefthook-local", ".lefthook-local"}
+)
 
 // NotFoundError wraps viper.ConfigFileNotFoundError for lefthook.
 type NotFoundError struct {
@@ -109,13 +113,21 @@ func mergeAll(fs afero.Fs, repo *git.Repository) (*viper.Viper, error) {
 		return nil, err
 	}
 
+	// Save global extends to compare them after merging local config
+	globalExtends := extends.GetStringSlice("extends")
+
 	if err := mergeRemotes(fs, repo, extends); err != nil {
 		return nil, err
 	}
 
-	if err := mergeOne([]string{"lefthook-local", ".lefthook-local"}, "", extends); err == nil {
-		if err = extend(extends, repo.RootPath); err != nil {
-			return nil, err
+	//nolint:nestif
+	if err := mergeLocal(extends); err == nil {
+		// Local extends need to be re-applied only if they have different settings
+		localExtends := extends.GetStringSlice("extends")
+		if !slices.Equal(globalExtends, localExtends) {
+			if err = extend(extends, repo.RootPath); err != nil {
+				return nil, err
+			}
 		}
 	} else {
 		var notFoundErr viper.ConfigFileNotFoundError
@@ -216,9 +228,9 @@ func merge(name, path string, v *viper.Viper) error {
 	return v.MergeInConfig()
 }
 
-func mergeOne(names []string, path string, v *viper.Viper) error {
-	for _, name := range names {
-		err := merge(name, path, v)
+func mergeLocal(v *viper.Viper) error {
+	for _, name := range localConfigNames {
+		err := merge(name, "", v)
 		if err == nil {
 			break
 		}
diff --git a/internal/config/load_test.go b/internal/config/load_test.go
index 76f0aa43..af54394e 100644
--- a/internal/config/load_test.go
+++ b/internal/config/load_test.go
@@ -612,6 +612,64 @@ pre-push:
 				},
 			},
 		},
+		{
+			name: "with extends and local",
+			global: `
+extends:
+  - global-extend.yml
+pre-commit:
+  parallel: true
+  exclude_tags: [linter]
+  commands:
+    global-lint:
+      run: bundle exec rubocop
+      glob: "*.rb"
+      tags: [backend, linter]
+    global-other:
+      run: bundle exec rubocop
+      tags: [other]
+`,
+			local: `
+pre-commit:
+  exclude_tags: [backend]
+`,
+			otherFiles: map[string]string{
+				"global-extend.yml": `
+pre-commit:
+  exclude_tags: [test]
+  commands:
+    extended-tests:
+      run: bundle exec rspec
+      tags: [backend, test]
+`,
+			},
+			result: &Config{
+				SourceDir:      DefaultSourceDir,
+				SourceDirLocal: DefaultSourceDirLocal,
+				Extends:        []string{"global-extend.yml"},
+				Hooks: map[string]*Hook{
+					"pre-commit": {
+						Parallel:    true,
+						ExcludeTags: []string{"backend"},
+						Commands: map[string]*Command{
+							"global-lint": {
+								Run:  "bundle exec rubocop",
+								Tags: []string{"backend", "linter"},
+								Glob: "*.rb",
+							},
+							"global-other": {
+								Run:  "bundle exec rubocop",
+								Tags: []string{"other"},
+							},
+							"extended-tests": {
+								Run:  "bundle exec rspec",
+								Tags: []string{"backend", "test"},
+							},
+						},
+					},
+				},
+			},
+		},
 	} {
 		fs := afero.Afero{Fs: afero.NewMemMapFs()}
 		repo := &git.Repository{