Add ability to view branches for a repo #141

Author: aryasoni98

pkg/github/repositories.go

@@ -79,6 +79,64 @@ func ListCommits(client *github.Client, t translations.TranslationHelperFunc) (t
 		}
 }
 
+// ListBranches creates a tool to list branches in a GitHub repository.
+func ListBranches(client *github.Client, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc) {
+	return mcp.NewTool("list_branches",
+			mcp.WithDescription(t("TOOL_LIST_BRANCHES_DESCRIPTION", "List branches in a GitHub repository")),
+			mcp.WithString("owner",
+				mcp.Required(),
+				mcp.Description("Repository owner"),
+			),
+			mcp.WithString("repo",
+				mcp.Required(),
+				mcp.Description("Repository name"),
+			),
+			WithPagination(),
+		),
+		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+			owner, err := requiredParam[string](request, "owner")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			repo, err := requiredParam[string](request, "repo")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+			pagination, err := OptionalPaginationParams(request)
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
+
+			opts := &github.BranchListOptions{
+				ListOptions: github.ListOptions{
+					Page:    pagination.page,
+					PerPage: pagination.perPage,
+				},
+			}
+
+			branches, resp, err := client.Repositories.ListBranches(ctx, owner, repo, opts)
+			if err != nil {
+				return nil, fmt.Errorf("failed to list branches: %w", err)
+			}
+			defer func() { _ = resp.Body.Close() }()
+
+			if resp.StatusCode != http.StatusOK {
+				body, err := io.ReadAll(resp.Body)
+				if err != nil {
+					return nil, fmt.Errorf("failed to read response body: %w", err)
+				}
+				return mcp.NewToolResultError(fmt.Sprintf("failed to list branches: %s", string(body))), nil
+			}
+
+			r, err := json.Marshal(branches)
+			if err != nil {
+				return nil, fmt.Errorf("failed to marshal response: %w", err)
+			}
+
+			return mcp.NewToolResultText(string(r)), nil
+		}
+}
+
 // CreateOrUpdateFile creates a tool to create or update a file in a GitHub repository.
 func CreateOrUpdateFile(client *github.Client, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc) {
 	return mcp.NewTool("create_or_update_file",

pkg/github/repositories_test.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"encoding/json"
 	"net/http"
+	"net/http/httptest"
+	"net/url"
 	"testing"
 	"time"
 
@@ -1293,3 +1295,104 @@ func Test_PushFiles(t *testing.T) {
 		})
 	}
 }
+
+func Test_ListBranches(t *testing.T) {
+	// Create a test server
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/repos/owner/repo/branches", r.URL.Path)
+		assert.Equal(t, "GET", r.Method)
+
+		// Check query parameters
+		query := r.URL.Query()
+		if page := query.Get("page"); page != "" {
+			assert.Equal(t, "2", page)
+		}
+		if perPage := query.Get("per_page"); perPage != "" {
+			assert.Equal(t, "30", perPage)
+		}
+
+		// Return mock branches
+		mockBranches := []github.Branch{
+			{Name: github.String("main")},
+			{Name: github.String("develop")},
+		}
+		mockResponse(t, http.StatusOK, mockBranches)(w, r)
+	}))
+	defer ts.Close()
+
+	// Create a GitHub client using the test server URL
+	client := github.NewClient(nil)
+	client.BaseURL, _ = url.Parse(ts.URL + "/")
+
+	// Create the tool
+	tool, handler := ListBranches(client, translations.NullTranslationHelper)
+
+	// Test cases
+	tests := []struct {
+		name        string
+		args        map[string]interface{}
+		wantErr     bool
+		errContains string
+	}{
+		{
+			name: "success",
+			args: map[string]interface{}{
+				"owner": "owner",
+				"repo":  "repo",
+				"page":  float64(2),
+			},
+			wantErr: false,
+		},
+		{
+			name: "missing owner",
+			args: map[string]interface{}{
+				"repo": "repo",
+			},
+			wantErr:     true,
+			errContains: "missing required parameter: owner",
+		},
+		{
+			name: "missing repo",
+			args: map[string]interface{}{
+				"owner": "owner",
+			},
+			wantErr:     true,
+			errContains: "missing required parameter: repo",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Create request
+			request := createMCPRequest(tt.args)
+
+			// Call handler
+			result, err := handler(context.Background(), request)
+			if tt.wantErr {
+				require.Error(t, err)
+				if tt.errContains != "" {
+					assert.Contains(t, err.Error(), tt.errContains)
+				}
+				return
+			}
+
+			require.NoError(t, err)
+			textContent := getTextResult(t, result)
+
+			// Verify response
+			var branches []github.Branch
+			err = json.Unmarshal([]byte(textContent.Text), &branches)
+			require.NoError(t, err)
+			assert.Len(t, branches, 2)
+			assert.Equal(t, "main", *branches[0].Name)
+			assert.Equal(t, "develop", *branches[1].Name)
+		})
+	}
+
+	// Verify tool definition
+	assert.Equal(t, "list_branches", tool.Name)
+	assert.Contains(t, tool.InputSchema.Required, "owner")
+	assert.Contains(t, tool.InputSchema.Required, "repo")
+	assert.NotContains(t, tool.InputSchema.Required, "page")
+	assert.NotContains(t, tool.InputSchema.Required, "perPage")
+}

pkg/github/server.go

@@ -60,6 +60,7 @@ func NewServer(client *github.Client, version string, readOnly bool, t translati
 	s.AddTool(SearchRepositories(client, t))
 	s.AddTool(GetFileContents(client, t))
 	s.AddTool(ListCommits(client, t))
+	s.AddTool(ListBranches(client, t))
 	if !readOnly {
 		s.AddTool(CreateOrUpdateFile(client, t))
 		s.AddTool(CreateRepository(client, t))