hide merge method step for merge queue

Author: skarim

.github/copilot-instructions.md

@@ -17,7 +17,7 @@ No Makefile, no code generation, no external linter config. Standard Go toolchai
 
 - `cmd/`: One Cobra command per file. Each exports `<Name>Cmd(cfg *config.Config)` with logic in `run<Name>()`.
 - `internal/git/`: `Ops` interface (52 methods) wrapping git CLI. `MockOps` for tests. Package-level functions delegate to swappable `ops` variable.
-- `internal/github/`: `ClientOps` interface (17 methods) for GitHub API. `MockClient` for tests. Stack operations use the public Stacks REST API (`/repos/{owner}/{repo}/stacks`); merges use the async merge API (`/repos/{owner}/{repo}/pulls/{n}/merge-async`), which routes to a direct merge or the base branch's merge queue automatically.
+- `internal/github/`: `ClientOps` interface (18 methods) for GitHub API. `MockClient` for tests. Stack operations use the public Stacks REST API (`/repos/{owner}/{repo}/stacks`); merges use the async merge API (`/repos/{owner}/{repo}/pulls/{n}/merge-async`), which routes to a direct merge or the base branch's merge queue automatically.
 - `internal/config/`: `Config` struct passed to all commands. Holds I/O, colors, and test hooks (`SelectFn`, `ConfirmFn`, `InputFn`, `GitHubClientOverride`).
 - `internal/stack/`: Stack file (`.git/gh-stack`, JSON) management with file locking.
 - `internal/tui/`: bubbletea views (`stackview`, `modifyview`).

AGENTS.md

@@ -35,7 +35,7 @@ internal/
     gitops.go                # Ops interface (52 methods)
     mock_ops.go              # MockOps. Each method has a corresponding *Fn field.
   github/                    # github.ClientOps interface + real Client
-    client_interface.go      # ClientOps interface (17 methods)
+    client_interface.go      # ClientOps interface (18 methods)
     mock_client.go           # MockClient. Uses function-pointer fields for testing.
   stack/                     # stack file (.git/gh-stack) management, JSON schema, locking
     schema.json              # JSON Schema for the stack file format

cmd/merge.go

@@ -127,25 +127,44 @@ func runMerge(cfg *config.Config, opts *mergeOptions, args []string) error {
 		return explainNothingToMerge(cfg, remoteStack, blocker)
 	}
 
-	mergeCfg, err := client.RepoMergeConfig()
-	if err != nil {
-		cfg.Errorf("failed to fetch repository merge settings: %s", err)
-		return ErrAPIFailure
-	}
-	allowed := mergeCfg.AllowedMethods()
-	if len(allowed) == 0 {
-		cfg.Errorf("this repository does not allow any merge methods")
-		return ErrAPIFailure
-	}
-	if method != "" && !mergeCfg.Allows(method) {
-		cfg.Errorf("this repository does not allow %s merges", method)
-		return ErrInvalidArgs
-	}
-
 	base := remoteStack.Base.Ref
 
+	// Detect whether the base branch merges through a merge queue so the wizard
+	// can skip the merge-method step and enqueue instead of merging directly.
+	usesMergeQueue := baseBranchUsesMergeQueue(client, base)
+
+	var mergeCfg *github.RepoMergeConfig
+	var allowed []string
+	if usesMergeQueue {
+		// The queue picks the merge method from its own configuration, so a
+		// requested method does not apply.
+		if method != "" {
+			cfg.Warningf("the base branch %q uses a merge queue; ignoring the merge method", base)
+			method = ""
+		}
+	} else {
+		mergeCfg, err = client.RepoMergeConfig()
+		if err != nil {
+			cfg.Errorf("failed to fetch repository merge settings: %s", err)
+			return ErrAPIFailure
+		}
+		allowed = mergeCfg.AllowedMethods()
+		if len(allowed) == 0 {
+			cfg.Errorf("this repository does not allow any merge methods")
+			return ErrAPIFailure
+		}
+		if method != "" && !mergeCfg.Allows(method) {
+			cfg.Errorf("this repository does not allow %s merges", method)
+			return ErrInvalidArgs
+		}
+	}
+
 	if cfg.IsInteractive() && !opts.yes {
-		return runMergeInteractive(cfg, client, remoteStack.Number, base, candidates, allowed, mergeCfg.DefaultMethod, method, preselectIndex, opts)
+		defaultMethod := ""
+		if mergeCfg != nil {
+			defaultMethod = mergeCfg.DefaultMethod
+		}
+		return runMergeInteractive(cfg, client, remoteStack.Number, base, candidates, allowed, defaultMethod, method, preselectIndex, usesMergeQueue, opts)
 	}
 
 	// Non-interactive (or --yes): merge the whole stack (or up to the given PR)
@@ -162,13 +181,13 @@ func runMerge(cfg *config.Config, opts *mergeOptions, args []string) error {
 		}
 		targetPR = candidates[len(candidates)-1].Number
 	}
-	if method == "" {
+	if !usesMergeQueue && method == "" {
 		method = mergeCfg.DefaultMethod
 		if !mergeCfg.Allows(method) {
 			method = allowed[0]
 		}
 	}
-	return runMergeHeadless(cfg, client, base, candidates, targetPR, method, opts)
+	return runMergeHeadless(cfg, client, base, candidates, targetPR, method, usesMergeQueue, opts)
 }
 
 // resolveMergeStack determines the remote stack (and any explicitly targeted PR)
@@ -275,7 +294,7 @@ func resolveActiveRemoteStack(cfg *config.Config, client github.ClientOps) (*git
 	return rs, nil
 }
 
-func runMergeInteractive(cfg *config.Config, client github.ClientOps, stackNumber int, base string, candidates []mergeview.PRItem, allowed []string, viewerDefault, methodFlag string, preselectIndex int, opts *mergeOptions) error {
+func runMergeInteractive(cfg *config.Config, client github.ClientOps, stackNumber int, base string, candidates []mergeview.PRItem, allowed []string, viewerDefault, methodFlag string, preselectIndex int, usesMergeQueue bool, opts *mergeOptions) error {
 	defaultMethod := viewerDefault
 	if methodFlag != "" {
 		defaultMethod = methodFlag
@@ -303,6 +322,7 @@ func runMergeInteractive(cfg *config.Config, client github.ClientOps, stackNumbe
 		AllowedMethods:    allowed,
 		DefaultMethod:     defaultMethod,
 		PreselectTopIndex: preselectIndex,
+		UsesMergeQueue:    usesMergeQueue,
 		Submit:            submit,
 		Poll:              poll,
 		PollInterval:      opts.pollInterval,
@@ -343,11 +363,15 @@ func runMergeInteractive(cfg *config.Config, client github.ClientOps, stackNumbe
 	}
 }
 
-func runMergeHeadless(cfg *config.Config, client github.ClientOps, base string, candidates []mergeview.PRItem, targetPR int, method string, opts *mergeOptions) error {
+func runMergeHeadless(cfg *config.Config, client github.ClientOps, base string, candidates []mergeview.PRItem, targetPR int, method string, usesMergeQueue bool, opts *mergeOptions) error {
 	nums := numbersUpTo(candidates, targetPR)
 	list := prNumberList(nums)
 
-	cfg.Printf("Merging %s into %s via %s...", list, base, method)
+	if usesMergeQueue {
+		cfg.Printf("Adding %s to the merge queue for %s...", list, base)
+	} else {
+		cfg.Printf("Merging %s into %s via %s...", list, base, method)
+	}
 
 	res, err := client.MergeStackAsync(targetPR, method)
 	if err != nil {
@@ -414,6 +438,19 @@ func runMergeHeadless(cfg *config.Config, client github.ClientOps, base string,
 	return ErrAPIFailure
 }
 
+// baseBranchUsesMergeQueue reports whether the stack's base branch merges through
+// a merge queue. Detection only tailors the wizard (skipping the method step and
+// switching to enqueue wording), so a lookup failure falls back to the
+// direct-merge flow: the async merge always sends merge_action "default" and the
+// server still routes to the queue when the branch requires one.
+func baseBranchUsesMergeQueue(client github.ClientOps, base string) bool {
+	uses, err := client.BaseBranchUsesMergeQueue(base)
+	if err != nil {
+		return false
+	}
+	return uses
+}
+
 // mergeFuncs returns submit/poll closures that adapt the GitHub client to the
 // mergeview injection points.
 func mergeFuncs(client github.ClientOps) (mergeview.SubmitFunc, mergeview.PollFunc) {

cmd/merge_test.go

@@ -131,6 +131,91 @@ func TestRunMerge_StackNumberArg(t *testing.T) {
 	assert.Contains(t, output, "Merged #10, #11 into main")
 }
 
+func TestRunMerge_MergeQueue_Headless(t *testing.T) {
+	gotMethod := "unset"
+	cfg, outR, errR := config.NewTestConfig()
+	cfg.GitHubClientOverride = &github.MockClient{
+		GetStackFn: func(n int) (*github.RemoteStack, error) {
+			return remoteStack(7, "main", openStackPR(10, "a"), openStackPR(11, "b")), nil
+		},
+		BaseBranchUsesMergeQueueFn: func(base string) (bool, error) {
+			assert.Equal(t, "main", base)
+			return true, nil
+		},
+		MergeStackAsyncFn: func(pr int, method string) (*github.AsyncMergeResult, error) {
+			gotMethod = method
+			return &github.AsyncMergeResult{
+				Status:  github.AsyncMergeStatusEnqueued,
+				Details: github.AsyncMergeDetails{Message: "Pull request was added to the merge queue."},
+			}, nil
+		},
+	}
+
+	err := runMerge(cfg, fastOptions(), []string{"7"})
+	output := collectOutput(cfg, outR, errR)
+
+	require.NoError(t, err)
+	assert.Equal(t, "", gotMethod, "a merge queue picks the method; none is sent")
+	assert.Contains(t, output, "merge queue")
+}
+
+func TestRunMerge_MergeQueue_IgnoresMethodFlag(t *testing.T) {
+	gotMethod := "unset"
+	cfg, outR, errR := config.NewTestConfig()
+	cfg.GitHubClientOverride = &github.MockClient{
+		GetStackFn: func(n int) (*github.RemoteStack, error) {
+			return remoteStack(7, "main", openStackPR(10, "a"), openStackPR(11, "b")), nil
+		},
+		BaseBranchUsesMergeQueueFn: func(base string) (bool, error) { return true, nil },
+		MergeStackAsyncFn: func(pr int, method string) (*github.AsyncMergeResult, error) {
+			gotMethod = method
+			return &github.AsyncMergeResult{
+				Status:  github.AsyncMergeStatusEnqueued,
+				Details: github.AsyncMergeDetails{Message: "queued"},
+			}, nil
+		},
+	}
+
+	opts := fastOptions()
+	opts.squash = true
+	err := runMerge(cfg, opts, []string{"7"})
+	output := collectOutput(cfg, outR, errR)
+
+	require.NoError(t, err)
+	assert.Equal(t, "", gotMethod, "the requested method is ignored under a merge queue")
+	assert.Contains(t, output, "ignoring the merge method")
+}
+
+func TestRunMerge_MergeQueueDetectionError_FallsBackToDirect(t *testing.T) {
+	gotMethod := "unset"
+	cfg, outR, errR := config.NewTestConfig()
+	cfg.GitHubClientOverride = &github.MockClient{
+		GetStackFn: func(n int) (*github.RemoteStack, error) {
+			return remoteStack(7, "main", openStackPR(10, "a"), openStackPR(11, "b")), nil
+		},
+		BaseBranchUsesMergeQueueFn: func(base string) (bool, error) {
+			return false, errors.New("boom")
+		},
+		RepoMergeConfigFn: func() (*github.RepoMergeConfig, error) {
+			return &github.RepoMergeConfig{MergeAllowed: true, DefaultMethod: "merge"}, nil
+		},
+		MergeStackAsyncFn: func(pr int, method string) (*github.AsyncMergeResult, error) {
+			gotMethod = method
+			return &github.AsyncMergeResult{
+				Status:  github.AsyncMergeStatusMerged,
+				Details: github.AsyncMergeDetails{SHA: "abc1234"},
+			}, nil
+		},
+	}
+
+	err := runMerge(cfg, fastOptions(), []string{"7"})
+	output := collectOutput(cfg, outR, errR)
+
+	require.NoError(t, err)
+	assert.Equal(t, "merge", gotMethod, "detection failure falls back to a direct merge with a method")
+	assert.Contains(t, output, "Merged")
+}
+
 func TestRunMerge_PRNumberArg(t *testing.T) {
 	var gotPR int
 	cfg, outR, errR := config.NewTestConfig()

internal/github/client_interface.go

@@ -21,6 +21,7 @@ type ClientOps interface {
 	MergeStackAsync(prNumber int, method string) (*AsyncMergeResult, error)
 	GetAsyncMergeResult(prNumber int, uuid string) (*AsyncMergeResult, error)
 	PRTitles(numbers []int) (map[int]string, error)
+	BaseBranchUsesMergeQueue(baseRef string) (bool, error)
 }
 
 // Compile-time check that Client satisfies ClientOps.

internal/github/merge_async.go

@@ -145,6 +145,53 @@ func (c *Client) RepoMergeConfig() (*RepoMergeConfig, error) {
 	}, nil
 }
 
+// BaseBranchUsesMergeQueue reports whether the given base branch merges through a
+// merge queue, detected via the branch's merge queue object or a MERGE_QUEUE
+// repository rule. It is used only to tailor the merge wizard (skipping the
+// merge-method step and switching to "enqueue" wording): the async stack merge
+// itself always sends merge_action "default", which lets the server route the
+// stack to the queue or a direct merge automatically.
+func (c *Client) BaseBranchUsesMergeQueue(baseRef string) (bool, error) {
+	var query struct {
+		Repository struct {
+			MergeQueue *struct {
+				ID string `graphql:"id"`
+			} `graphql:"mergeQueue(branch: $branch)"`
+			Ref *struct {
+				Rules struct {
+					Nodes []struct {
+						Type string `graphql:"type"`
+					} `graphql:"nodes"`
+				} `graphql:"rules(first: 50)"`
+			} `graphql:"ref(qualifiedName: $qualified)"`
+		} `graphql:"repository(owner: $owner, name: $name)"`
+	}
+
+	variables := map[string]interface{}{
+		"owner":     graphql.String(c.owner),
+		"name":      graphql.String(c.repo),
+		"branch":    graphql.String(baseRef),
+		"qualified": graphql.String("refs/heads/" + baseRef),
+	}
+
+	if err := c.gql.Query("BaseBranchMergeQueue", &query, variables); err != nil {
+		return false, fmt.Errorf("querying base branch merge queue: %w", err)
+	}
+
+	r := query.Repository
+	if r.MergeQueue != nil {
+		return true, nil
+	}
+	if r.Ref != nil {
+		for _, node := range r.Ref.Rules.Nodes {
+			if node.Type == "MERGE_QUEUE" {
+				return true, nil
+			}
+		}
+	}
+	return false, nil
+}
+
 // MergeStackAsync requests an asynchronous merge of the given pull request. For
 // a stacked PR this merges all members of the stack up to and including
 // prNumber. A blank method lets the server apply its default.

internal/github/mock_client.go

@@ -4,23 +4,24 @@ package github
 // Each field is an optional function that, when set, handles the corresponding
 // ClientOps method call. When nil, a reasonable default is returned.
 type MockClient struct {
-	FindPRForBranchFn        func(string) (*PullRequest, error)
-	FindPRByNumberFn         func(int) (*PullRequest, error)
-	FindPRDetailsForBranchFn func(string) (*PRDetails, error)
-	CreatePRFn               func(string, string, string, string, bool) (*PullRequest, error)
-	UpdatePRBaseFn           func(int, string) error
-	MarkPRReadyForReviewFn   func(string) error
-	DisableAutoMergeFn       func(string) error
-	ListStacksFn             func() ([]RemoteStack, error)
-	FindStackForPRFn         func(int) (*RemoteStack, error)
-	GetStackFn               func(int) (*RemoteStack, error)
-	CreateStackFn            func([]int) (*RemoteStack, error)
-	AddToStackFn             func(int, []int) (*RemoteStack, error)
-	UnstackFn                func(int) (*RemoteStack, bool, error)
-	RepoMergeConfigFn        func() (*RepoMergeConfig, error)
-	MergeStackAsyncFn        func(int, string) (*AsyncMergeResult, error)
-	GetAsyncMergeResultFn    func(int, string) (*AsyncMergeResult, error)
-	PRTitlesFn               func([]int) (map[int]string, error)
+	FindPRForBranchFn          func(string) (*PullRequest, error)
+	FindPRByNumberFn           func(int) (*PullRequest, error)
+	FindPRDetailsForBranchFn   func(string) (*PRDetails, error)
+	CreatePRFn                 func(string, string, string, string, bool) (*PullRequest, error)
+	UpdatePRBaseFn             func(int, string) error
+	MarkPRReadyForReviewFn     func(string) error
+	DisableAutoMergeFn         func(string) error
+	ListStacksFn               func() ([]RemoteStack, error)
+	FindStackForPRFn           func(int) (*RemoteStack, error)
+	GetStackFn                 func(int) (*RemoteStack, error)
+	CreateStackFn              func([]int) (*RemoteStack, error)
+	AddToStackFn               func(int, []int) (*RemoteStack, error)
+	UnstackFn                  func(int) (*RemoteStack, bool, error)
+	RepoMergeConfigFn          func() (*RepoMergeConfig, error)
+	MergeStackAsyncFn          func(int, string) (*AsyncMergeResult, error)
+	GetAsyncMergeResultFn      func(int, string) (*AsyncMergeResult, error)
+	PRTitlesFn                 func([]int) (map[int]string, error)
+	BaseBranchUsesMergeQueueFn func(string) (bool, error)
 }
 
 // Compile-time check that MockClient satisfies ClientOps.
@@ -162,3 +163,10 @@ func (m *MockClient) PRTitles(numbers []int) (map[int]string, error) {
 	}
 	return map[int]string{}, nil
 }
+
+func (m *MockClient) BaseBranchUsesMergeQueue(baseRef string) (bool, error) {
+	if m.BaseBranchUsesMergeQueueFn != nil {
+		return m.BaseBranchUsesMergeQueueFn(baseRef)
+	}
+	return false, nil
+}