From f9567f0d4fc5cf6d0e1cea2d22289250c6b1cb2b Mon Sep 17 00:00:00 2001
From: Shulhan <ms@kilabit.info>
Date: Mon, 5 Jan 2026 21:47:09 +0700
Subject: lib/git: implement Equaler interface on Git

The Equaler interface provide the method Equal that when implemented
can be used to compare two instances of struct.
---
 lib/git/git.go              | 23 ++++++++++++++++++++++
 lib/git/git_example_test.go | 31 +++++++++++++++++++++++++++++
 lib/git/git_test.go         | 48 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+)

diff --git a/lib/git/git.go b/lib/git/git.go
index 02877281..1fc5fde3 100644
--- a/lib/git/git.go
+++ b/lib/git/git.go
@@ -144,6 +144,24 @@ func Clone(remoteURL, dest string) (err error) {
 	return nil
 }
 
+// Equal return true if `v` is instance of `*Git` and has the same working
+// directory.
+// This implement [git.sr.ht/~shulhan/pakakeh.go/lib/reflect.Equaler]
+// interface.
+func (git *Git) Equal(v any) bool {
+	if v == nil {
+		return false
+	}
+	got, ok := v.(*Git)
+	if !ok {
+		return false
+	}
+	if got == nil {
+		return false
+	}
+	return git.String() == got.String()
+}
+
 // FetchAll will fetch the latest commits and tags from remote.
 func FetchAll(repoDir string) (err error) {
 	cmd := exec.Command("git", "fetch")
@@ -439,3 +457,8 @@ func RemoteBranches(repoDir string) ([]string, error) {
 
 	return branches, nil
 }
+
+// String return the working directory with prefix "git+file://".
+func (git *Git) String() string {
+	return `git+file://` + git.absDir
+}
diff --git a/lib/git/git_example_test.go b/lib/git/git_example_test.go
index 0b55a251..968d4431 100644
--- a/lib/git/git_example_test.go
+++ b/lib/git/git_example_test.go
@@ -40,3 +40,34 @@ func ExampleGit_IsIgnored() {
 	// "hello.go": false
 	// "foo/hello.go": false
 }
+
+func ExampleGit_Equal() {
+	var agit *git.Git
+	var err error
+	agit, err = git.New(`testdata/Equal`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var vgit *git.Git
+	var dir = `testdata/IsIgnored`
+
+	vgit, err = git.New(dir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	var got = agit.Equal(vgit)
+	fmt.Printf("On git %s: Equal is %t\n", dir, got)
+
+	dir = `testdata/Equal`
+	vgit, err = git.New(dir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	got = agit.Equal(vgit)
+	fmt.Printf("On git %s: Equal is %t\n", dir, got)
+
+	// Output:
+	// On git testdata/IsIgnored: Equal is false
+	// On git testdata/Equal: Equal is true
+}
diff --git a/lib/git/git_test.go b/lib/git/git_test.go
index 70a9ccca..65fe572d 100644
--- a/lib/git/git_test.go
+++ b/lib/git/git_test.go
@@ -134,6 +134,35 @@ Use '--' to separate paths from revisions, like this:
 	}
 }
 
+func TestGit_Equal(t *testing.T) {
+	type testCase struct {
+		v   any
+		exp bool
+	}
+	var nilgit *Git
+	var listCase = []testCase{{
+		v: nil,
+	}, {
+		v: os.ErrExist,
+	}, {
+		v: nilgit,
+	}}
+
+	var agit *Git
+	var err error
+	agit, err = New(`testdata/Equal`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var tc testCase
+	var got bool
+	for _, tc = range listCase {
+		got = agit.Equal(tc.v)
+		test.Assert(t, fmt.Sprintf(`%T`, tc.v), tc.exp, got)
+	}
+}
+
 func TestGetRemoteURL(t *testing.T) {
 	cases := []struct {
 		desc                 string
@@ -393,3 +422,22 @@ func TestRemoteChange(t *testing.T) {
 		test.Assert(t, "stdout", c.expStdout, mockStdout.String())
 	}
 }
+
+func TestGit_String(t *testing.T) {
+	var agit *Git
+	var err error
+	agit, err = New(`testdata/Equal`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var wd string
+	wd, err = os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var exp = fmt.Sprintf(`git+file://%s/testdata/Equal`, wd)
+	var got = agit.String()
+	test.Assert(t, `String`, exp, got)
+}
-- 
cgit v1.3