Add GetLatestTag function with no-tags existence check

yyle88 · yangyile1990 · commit 5c96a2b8873d · 2025-11-24T10:19:03.000+07:00
- Add GetLatestTag() returning (tag, exists, error) tuple
- Use WithExpectExit(128, "NO-TAGS") pattern to handle missing tags
- When no tags exist, return ("", false, nil)
- Update demo3x example with improved log messages
- Add Tag Operations section to README.md and README.zh.md
- Add comprehensive tests with ZeroTags, OneTag, and TwoTags scenarios
diff --git a/README.md b/README.md
@@ -146,7 +146,7 @@ func main() {
 
 	gcm := gitgo.New(tempDIR)
 	gcm.Init().Done()
-	zaplog.SUG.Info("repo ready")
+	zaplog.SUG.Info("repo setup complete")
 
 	must.Done(os.WriteFile(filepath.Join(tempDIR, "app.txt"), []byte("v1"), 0644))
 	gcm.Add().Commit("v1").Tag("v1.0.0").Done()
@@ -160,7 +160,7 @@ func main() {
 	zaplog.SUG.Info("latest tag:", latest)
 
 	count := rese.V1(gcm.GetCommitCount())
-	zaplog.SUG.Info("total commits:", count)
+	zaplog.SUG.Info("commit count:", count)
 }
 ```
 
@@ -198,6 +198,11 @@ func main() {
 - `GetRemoteURL(remote) (string, error)` - Get remote repo URL
 - `GetIgnoredFiles() ([]string, error)` - Get files ignored in gitignore
 
+### Tag Operations
+
+- `LatestGitTag() (string, error)` - Get latest tag name (fails when no tags exist)
+- `GetLatestTag() (string, bool, error)` - Get latest tag name with existence check
+
 ### Issue Handling
 
 - `Result() ([]byte, error)` - Get output and check issues
diff --git a/README.zh.md b/README.zh.md
@@ -146,7 +146,7 @@ func main() {
 
 	gcm := gitgo.New(tempDIR)
 	gcm.Init().Done()
-	zaplog.SUG.Info("repo ready")
+	zaplog.SUG.Info("repo setup complete")
 
 	must.Done(os.WriteFile(filepath.Join(tempDIR, "app.txt"), []byte("v1"), 0644))
 	gcm.Add().Commit("v1").Tag("v1.0.0").Done()
@@ -160,7 +160,7 @@ func main() {
 	zaplog.SUG.Info("latest tag:", latest)
 
 	count := rese.V1(gcm.GetCommitCount())
-	zaplog.SUG.Info("total commits:", count)
+	zaplog.SUG.Info("commit count:", count)
 }
 ```
 
@@ -198,6 +198,11 @@ func main() {
 - `GetRemoteURL(remote) (string, error)` - 获取远程仓库 URL
 - `GetIgnoredFiles() ([]string, error)` - 获取 gitignore 忽略的文件
 
+### 标签操作
+
+- `LatestGitTag() (string, error)` - 获取最新标签名称（没有标签时会失败）
+- `GetLatestTag() (string, bool, error)` - 获取最新标签名称并检查是否存在
+
 ### 问题处理
 
 - `Result() ([]byte, error)` - 获取输出并检查问题
diff --git a/git_up.go b/git_up.go
@@ -128,6 +128,28 @@ func (G *Gcm) LatestGitTag() (string, error) {
 	return strings.TrimSpace(string(output)), nil
 }
 
+// GetLatestTag retrieves the latest tag name if it exists
+// Returns tag name, exists flag, and possible errors
+// When no tags exist, returns ("", false, nil)
+//
+// GetLatestTag 获取最新标签名称（如果存在）
+// 返回标签名称、存在标志和可能的错误
+// 当没有标签时，返回 ("", false, nil)
+func (G *Gcm) GetLatestTag() (string, bool, error) {
+	output, exc, err := G.execConfig.NewConfig().WithExpectExit(128, "NO-TAGS").ExecTake("git", "describe", "--tags", "--abbrev=0")
+	if err != nil {
+		return "", false, erero.Wro(err)
+	}
+	switch exc {
+	case 0:
+		return strings.TrimSpace(string(output)), true, nil // Tag exists // 标签存在
+	case 128:
+		return "", false, nil // No tags exist // 没有标签
+	default:
+		return "", false, erero.Errorf("git describe failed with exit code %d", exc)
+	}
+}
+
 // LatestGitTagHasPrefix retrieves the latest tag name with the specified prefix
 // Returns the most recent tag that starts with the given prefix
 // Helps find version tags on specific subprojects and components
diff --git a/git_up_test.go b/git_up_test.go
@@ -776,6 +776,105 @@ func TestGcm_LatestGitTag_Temp(t *testing.T) {
 	require.Equal(t, "v2.0.0", tag)
 }
 
+// TestGetLatestTag tests GetLatestTag with 0, 1, and 2 tags scenarios
+// Verifies correct handling when no tags exist, one tag exists, and multiple tags exist
+//
+// TestGetLatestTag 测试 GetLatestTag 在 0、1、2 个标签场景
+// 验证在没有标签、1个标签和多个标签时的处理
+func TestGetLatestTag(t *testing.T) {
+	t.Run("ZeroTags", func(t *testing.T) {
+		// Create temp DIR with git repo but no tags
+		// 创建临时目录和 git 仓库但不创建标签
+		tempDIR := rese.V1(os.MkdirTemp("", "gitgo-get-latest-tag-zero-*"))
+		defer func() {
+			must.Done(os.RemoveAll(tempDIR))
+		}()
+
+		gcm := gitgo.New(tempDIR)
+		gcm.Init().Done()
+
+		// Create initial commit
+		// 创建初始提交
+		must.Done(os.WriteFile(filepath.Join(tempDIR, "init.txt"), []byte("init"), 0644))
+		gcm.Add().Commit("initial").Done()
+
+		// Test GetLatestTag with no tags
+		// 测试没有标签时的 GetLatestTag
+		tag, exists, err := gcm.GetLatestTag()
+		require.NoError(t, err)
+		require.False(t, exists)
+		require.Equal(t, "", tag)
+		t.Log("No tags: exists=", exists)
+	})
+
+	t.Run("OneTag", func(t *testing.T) {
+		// Create temp DIR with git repo and one tag
+		// 创建临时目录、git 仓库和一个标签
+		tempDIR := rese.V1(os.MkdirTemp("", "gitgo-get-latest-tag-one-*"))
+		defer func() {
+			must.Done(os.RemoveAll(tempDIR))
+		}()
+
+		gcm := gitgo.New(tempDIR)
+		gcm.Init().Done()
+
+		// Create initial commit
+		// 创建初始提交
+		must.Done(os.WriteFile(filepath.Join(tempDIR, "init.txt"), []byte("init"), 0644))
+		gcm.Add().Commit("initial").Done()
+
+		// Create one tag
+		// 创建一个标签
+		gcm.Tag("v0.0.1").Done()
+
+		// Test GetLatestTag with one tag
+		// 测试存在一个标签时的 GetLatestTag
+		tag, exists, err := gcm.GetLatestTag()
+		require.NoError(t, err)
+		require.True(t, exists)
+		require.Equal(t, "v0.0.1", tag)
+		t.Log("One tag: tag=", tag, "exists=", exists)
+	})
+
+	t.Run("TwoTags", func(t *testing.T) {
+		// Create temp DIR with git repo and two tags
+		// 创建临时目录、git 仓库和两个标签
+		tempDIR := rese.V1(os.MkdirTemp("", "gitgo-get-latest-tag-two-*"))
+		defer func() {
+			must.Done(os.RemoveAll(tempDIR))
+		}()
+
+		gcm := gitgo.New(tempDIR)
+		gcm.Init().Done()
+
+		// Create initial commit
+		// 创建初始提交
+		must.Done(os.WriteFile(filepath.Join(tempDIR, "init.txt"), []byte("init"), 0644))
+		gcm.Add().Commit("initial").Done()
+
+		// Create first tag
+		// 创建第一个标签
+		gcm.Tag("v0.0.1").Done()
+
+		// Create second commit
+		// 创建第二次提交
+		must.Done(os.WriteFile(filepath.Join(tempDIR, "second.txt"), []byte("second"), 0644))
+		gcm.Add().Commit("second").Done()
+
+		// Create second tag
+		// 创建第二个标签
+		gcm.Tag("v0.0.2").Done()
+
+		// Test GetLatestTag with two tags, should get the latest one
+		// 测试存在两个标签时的 GetLatestTag，应该获取最新的标签
+		tag, exists, err := gcm.GetLatestTag()
+		require.NoError(t, err)
+		require.True(t, exists)
+		require.Equal(t, "v0.0.2", tag)
+		t.Log("Two tags: tag=", tag, "exists=", exists)
+	})
+}
+
 // TestGcm_GetBranchTrackingBranch tests getting upstream branch
 // Verifies GetBranchTrackingBranch returns correct tracking info
 //
diff --git a/internal/demos/demo3x/main.go b/internal/demos/demo3x/main.go
@@ -20,7 +20,7 @@ func main() {
 
 	gcm := gitgo.New(tempDIR)
 	gcm.Init().Done()
-	zaplog.SUG.Info("repo ready")
+	zaplog.SUG.Info("repo setup complete")
 
 	must.Done(os.WriteFile(filepath.Join(tempDIR, "app.txt"), []byte("v1"), 0644))
 	gcm.Add().Commit("v1").Tag("v1.0.0").Done()
@@ -34,5 +34,5 @@ func main() {
 	zaplog.SUG.Info("latest tag:", latest)
 
 	count := rese.V1(gcm.GetCommitCount())
-	zaplog.SUG.Info("total commits:", count)
+	zaplog.SUG.Info("commit count:", count)
 }
