feat(repo): add rename_branch tool (#245)

Adds a native `rename_branch` write tool so MCP clients can rename branches without emulating it via create + delete.

Changes:
- Add `rename_branch` to the repository branch tools with `owner`, `repo`, `branch`, and `new_name` parameters.
- Call the Gitea SDK's `RenameRepoBranch` operation and propagate API errors.
- Add handler/registration tests and README tool table entries.

Closes https://gitea.com/gitea/gitea-mcp/issues/236

Assisted by Codet

Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/245
Reviewed-by: silverwind <2021+silverwind@noreply.gitea.com>

README.md

@@ -180,6 +180,7 @@ Once configured, try `list all my repositories` in the chat box.
 | create_branch                | branch       | Write  | Create a new branch |
 | delete_branch                | branch       | Write  | Delete a branch |
 | list_branches                | branch       | Read   | List repository branches |
+| rename_branch                | branch       | Write  | Rename a branch |
 | create_tag                   | tag          | Write  | Create a tag |
 | delete_tag                   | tag          | Write  | Delete a tag |
 | get_tag                      | tag          | Read   | Get tag details |

README.zh-cn.md

@@ -180,6 +180,7 @@ Cursor 等客户端可使用 stdio 命令：
 | create_branch                | branch       | 写入 | 创建新分支 |
 | delete_branch                | branch       | 写入 | 删除分支 |
 | list_branches                | branch       | 读取 | 列出仓库分支 |
+| rename_branch                | branch       | 写入 | 重命名分支 |
 | create_tag                   | tag          | 写入 | 创建标签 |
 | delete_tag                   | tag          | 写入 | 删除标签 |
 | get_tag                      | tag          | 读取 | 获取标签详情 |

README.zh-tw.md

@@ -180,6 +180,7 @@ Cursor 等客戶端可使用 stdio 命令：
 | create_branch                | branch       | 寫入 | 創建新分支 |
 | delete_branch                | branch       | 寫入 | 刪除分支 |
 | list_branches                | branch       | 讀取 | 列出倉庫分支 |
+| rename_branch                | branch       | 寫入 | 重新命名分支 |
 | create_tag                   | tag          | 寫入 | 創建標籤 |
 | delete_tag                   | tag          | 寫入 | 刪除標籤 |
 | get_tag                      | tag          | 讀取 | 取得標籤詳情 |

operation/repo/branch.go

@@ -2,6 +2,7 @@ package repo
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"gitea.com/gitea/gitea-mcp/pkg/annotation"
@@ -21,6 +22,7 @@ const (
 	CreateBranchToolName = "create_branch"
 	DeleteBranchToolName = "delete_branch"
 	ListBranchesToolName = "list_branches"
+	RenameBranchToolName = "rename_branch"
 )
 
 var (
@@ -52,6 +54,16 @@ var (
 		tool.Number("page", tool.Description(params.PageDesc), tool.Default(1)),
 		tool.Number("per_page", tool.Description(params.PaginationDesc), tool.Default(30)),
 	)
+
+	RenameBranchTool = tool.NewDefinition(
+		RenameBranchToolName,
+		"Rename an existing branch in a repository.",
+		annotation.Write("Rename a branch"),
+		tool.String("owner", tool.Required(), tool.Description(params.OwnerDesc)),
+		tool.String("repo", tool.Required(), tool.Description(params.RepoDesc)),
+		tool.String("branch", tool.Required()),
+		tool.String("new_name", tool.Required()),
+	)
 )
 
 func init() {
@@ -67,6 +79,10 @@ func init() {
 		Tool:    ListBranchesTool,
 		Handler: ListBranchesFn,
 	})
+	BranchTool.RegisterWrite(tool.ServerTool{
+		Tool:    RenameBranchTool,
+		Handler: RenameBranchFn,
+	})
 }
 
 func CreateBranchFn(ctx context.Context, args map[string]any) (*mcp.CallToolResult, error) {
@@ -149,3 +165,36 @@ func ListBranchesFn(ctx context.Context, args map[string]any) (*mcp.CallToolResu
 
 	return to.TextResult(slimBranches(branches))
 }
+
+func RenameBranchFn(ctx context.Context, args map[string]any) (*mcp.CallToolResult, error) {
+	owner, err := params.GetString(args, "owner")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	repo, err := params.GetString(args, "repo")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	branch, err := params.GetString(args, "branch")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	newName, err := params.GetString(args, "new_name")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+
+	client, err := gitea.ClientFromContext(ctx)
+	if err != nil {
+		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
+	}
+	successful, _, err := client.Repositories.RenameRepoBranch(ctx, owner, repo, branch, gitea_sdk.RenameRepoBranchOption{Name: newName})
+	if err != nil {
+		return to.ErrorResult(fmt.Errorf("rename branch error: %v", err))
+	}
+	if !successful {
+		return to.ErrorResult(errors.New("rename branch error: unsuccessful"))
+	}
+
+	return to.TextResult("Branch renamed")
+}

operation/repo/branch_test.go

@@ -0,0 +1,136 @@
+package repo
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"testing"
+
+	"gitea.com/gitea/gitea-mcp/pkg/flag"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+)
+
+func TestRenameBranchFnMissingArgs(t *testing.T) {
+	fullArgs := map[string]any{
+		"owner":    "octo",
+		"repo":     "demo",
+		"branch":   "old-name",
+		"new_name": "new-name",
+	}
+
+	for _, missing := range []string{"owner", "repo", "branch", "new_name"} {
+		t.Run(missing, func(t *testing.T) {
+			args := map[string]any{}
+			for k, v := range fullArgs {
+				if k != missing {
+					args[k] = v
+				}
+			}
+
+			result, err := RenameBranchFn(context.Background(), args)
+			if err != nil {
+				t.Fatalf("RenameBranchFn() error = %v", err)
+			}
+			if !result.IsError {
+				t.Fatalf("RenameBranchFn() with missing %q, want error result", missing)
+			}
+		})
+	}
+}
+
+func TestRenameBranchFn(t *testing.T) {
+	const (
+		owner   = "octo"
+		repo    = "demo"
+		branch  = "old-name"
+		newName = "new-name"
+	)
+
+	for _, tc := range []struct {
+		name         string
+		serverStatus int
+		wantErr      bool
+		wantContains string
+	}{
+		{"success", http.StatusNoContent, false, "Branch renamed"},
+		{"server error", http.StatusInternalServerError, true, "rename branch error"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			var (
+				mu      sync.Mutex
+				gotBody map[string]any
+			)
+
+			renamePath := fmt.Sprintf("/api/v1/repos/%s/%s/branches/%s", owner, repo, branch)
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				switch r.URL.Path {
+				case "/api/v1/version":
+					_, _ = w.Write([]byte(`{"version":"1.24.0"}`))
+				case renamePath:
+					mu.Lock()
+					_ = json.NewDecoder(r.Body).Decode(&gotBody)
+					mu.Unlock()
+					w.WriteHeader(tc.serverStatus)
+				default:
+					http.NotFound(w, r)
+				}
+			}))
+			defer server.Close()
+
+			origHost, origToken := flag.Host, flag.Token
+			flag.Host, flag.Token = server.URL, ""
+			defer func() { flag.Host, flag.Token = origHost, origToken }()
+
+			result, err := RenameBranchFn(context.Background(), map[string]any{
+				"owner":    owner,
+				"repo":     repo,
+				"branch":   branch,
+				"new_name": newName,
+			})
+			if err != nil {
+				t.Fatalf("RenameBranchFn() error = %v", err)
+			}
+
+			if result.IsError != tc.wantErr {
+				t.Fatalf("RenameBranchFn() IsError = %v, want %v (result: %v)", result.IsError, tc.wantErr, result)
+			}
+
+			text := result.Content[0].(*mcp.TextContent).Text
+			if !strings.Contains(text, tc.wantContains) {
+				t.Fatalf("result = %s, want it to contain %q", text, tc.wantContains)
+			}
+
+			if !tc.wantErr {
+				mu.Lock()
+				defer mu.Unlock()
+				if gotBody["name"] != newName {
+					t.Fatalf("request body name = %v, want %s", gotBody["name"], newName)
+				}
+			}
+		})
+	}
+}
+
+func TestRenameBranchToolRegistration(t *testing.T) {
+	found := false
+	for _, registered := range BranchTool.WriteTools() {
+		if registered.Tool.Name == RenameBranchToolName {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatalf("%q is not registered as a write tool", RenameBranchToolName)
+	}
+
+	for _, registered := range BranchTool.ReadTools() {
+		if registered.Tool.Name == RenameBranchToolName {
+			t.Fatalf("%q is registered as a read tool, want write only", RenameBranchToolName)
+		}
+	}
+}