GH-2211: Wire native sub-issue linking into epic decomposition (internal/executor/)

cmd/pilot/main.go

@@ -714,6 +714,9 @@ Examples:
 						}
 					}
 
+					// GH-2211: Wire native sub-issue linker so epic children get proper parent→child links
+					gwRunner.SetSubIssueLinker(client)
+
 					// GH-726: Wire processed issue persistence for gateway poller
 					if gwAutopilotStateStore != nil {
 						pollerOpts = append(pollerOpts, github.WithProcessedStore(gwAutopilotStateStore))

internal/executor/epic.go

@@ -563,6 +563,24 @@ func (r *Runner) createSubIssuesViaGitHub(ctx context.Context, plan *EpicPlan, e
 		// Track order → issue number for dependency resolution (GH-1794)
 		orderToIssueNumber[subtask.Order] = issueNumber
 
+		// GH-2211: Wire native GitHub sub-issue link (non-fatal — text marker is fallback)
+		if r.subIssueLinker != nil &&
+			plan.ParentTask != nil &&
+			plan.ParentTask.SourceRepo != "" &&
+			plan.ParentTask.SourceIssueID != "" {
+			if parts := strings.SplitN(plan.ParentTask.SourceRepo, "/", 2); len(parts) == 2 {
+				if parentNum, parseErr := strconv.Atoi(plan.ParentTask.SourceIssueID); parseErr == nil {
+					if linkErr := r.subIssueLinker.LinkSubIssue(ctx, parts[0], parts[1], parentNum, issueNumber); linkErr != nil {
+						r.log.Warn("Failed to link native sub-issue",
+							"parent", parentNum,
+							"child", issueNumber,
+							"error", linkErr,
+						)
+					}
+				}
+			}
+		}
+
 		r.log.Info("Created GitHub issue",
 			"subtask_order", subtask.Order,
 			"issue_number", issueNumber,

internal/executor/epic_test.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 )
@@ -1423,3 +1424,174 @@ func TestCreatedIssue_IdentifierField(t *testing.T) {
 		})
 	}
 }
+
+// mockSubIssueLinker records LinkSubIssue calls for test assertions.
+type mockSubIssueLinker struct {
+	mu     sync.Mutex
+	Calls  []mockLinkSubIssueCall
+	ErrFn  func(owner, repo string, parentNum, childNum int) error // optional error injection
+}
+
+type mockLinkSubIssueCall struct {
+	Owner     string
+	Repo      string
+	ParentNum int
+	ChildNum  int
+}
+
+func (m *mockSubIssueLinker) LinkSubIssue(_ context.Context, owner, repo string, parentNum, childNum int) error {
+	m.mu.Lock()
+	m.Calls = append(m.Calls, mockLinkSubIssueCall{owner, repo, parentNum, childNum})
+	m.mu.Unlock()
+	if m.ErrFn != nil {
+		return m.ErrFn(owner, repo, parentNum, childNum)
+	}
+	return nil
+}
+
+func TestSetSubIssueLinker_WiresField(t *testing.T) {
+	r := NewRunner()
+	if r.subIssueLinker != nil {
+		t.Fatal("expected nil subIssueLinker before Set")
+	}
+	mock := &mockSubIssueLinker{}
+	r.SetSubIssueLinker(mock)
+	if r.subIssueLinker == nil {
+		t.Fatal("expected non-nil subIssueLinker after Set")
+	}
+}
+
+func TestCreateSubIssues_LinkerInvokedAfterGhCreate(t *testing.T) {
+	// Use a fake "gh" binary that echoes a fake issue URL so the CLI path succeeds.
+	fakeBin := t.TempDir()
+	script := filepath.Join(fakeBin, "gh")
+	err := os.WriteFile(script, []byte("#!/bin/sh\necho https://github.com/owner/testrepo/issues/42\n"), 0o755)
+	if err != nil {
+		t.Fatalf("write fake gh: %v", err)
+	}
+	origPATH := os.Getenv("PATH")
+	t.Setenv("PATH", fakeBin+string(filepath.ListSeparator)+origPATH)
+
+	mock := &mockSubIssueLinker{}
+	runner := NewRunner()
+	runner.SetSubIssueLinker(mock)
+
+	plan := &EpicPlan{
+		ParentTask: &Task{
+			ID:            "GH-10",
+			SourceRepo:    "owner/testrepo",
+			SourceIssueID: "10",
+		},
+		Subtasks: []PlannedSubtask{
+			{Title: "Child task", Description: "Do it", Order: 1},
+		},
+	}
+
+	ctx := context.Background()
+	created, err := runner.CreateSubIssues(ctx, plan, t.TempDir())
+	if err != nil {
+		t.Fatalf("CreateSubIssues failed: %v", err)
+	}
+	if len(created) != 1 {
+		t.Fatalf("expected 1 created issue, got %d", len(created))
+	}
+	if created[0].Number != 42 {
+		t.Errorf("issue number = %d, want 42", created[0].Number)
+	}
+
+	// Linker must have been called exactly once with the right args
+	if len(mock.Calls) != 1 {
+		t.Fatalf("expected 1 LinkSubIssue call, got %d", len(mock.Calls))
+	}
+	call := mock.Calls[0]
+	if call.Owner != "owner" {
+		t.Errorf("owner = %q, want owner", call.Owner)
+	}
+	if call.Repo != "testrepo" {
+		t.Errorf("repo = %q, want testrepo", call.Repo)
+	}
+	if call.ParentNum != 10 {
+		t.Errorf("parentNum = %d, want 10", call.ParentNum)
+	}
+	if call.ChildNum != 42 {
+		t.Errorf("childNum = %d, want 42", call.ChildNum)
+	}
+}
+
+func TestCreateSubIssues_LinkerErrorIsNonFatal(t *testing.T) {
+	// Fake "gh" binary returns a valid URL; linker returns an error.
+	// CreateSubIssues must still succeed (linker error is warn-only).
+	fakeBin := t.TempDir()
+	script := filepath.Join(fakeBin, "gh")
+	err := os.WriteFile(script, []byte("#!/bin/sh\necho https://github.com/owner/testrepo/issues/99\n"), 0o755)
+	if err != nil {
+		t.Fatalf("write fake gh: %v", err)
+	}
+	origPATH := os.Getenv("PATH")
+	t.Setenv("PATH", fakeBin+string(filepath.ListSeparator)+origPATH)
+
+	mock := &mockSubIssueLinker{
+		ErrFn: func(_, _ string, _, _ int) error {
+			return fmt.Errorf("graphql mutation failed")
+		},
+	}
+	runner := NewRunner()
+	runner.SetSubIssueLinker(mock)
+
+	plan := &EpicPlan{
+		ParentTask: &Task{
+			ID:            "GH-5",
+			SourceRepo:    "owner/testrepo",
+			SourceIssueID: "5",
+		},
+		Subtasks: []PlannedSubtask{
+			{Title: "Child", Description: "child", Order: 1},
+		},
+	}
+
+	ctx := context.Background()
+	created, err := runner.CreateSubIssues(ctx, plan, t.TempDir())
+	if err != nil {
+		t.Fatalf("CreateSubIssues must succeed even when linker errors: %v", err)
+	}
+	if len(created) != 1 {
+		t.Fatalf("expected 1 created issue, got %d", len(created))
+	}
+	// Linker was called (and returned error) but creation succeeded
+	if len(mock.Calls) != 1 {
+		t.Errorf("expected linker called once, got %d", len(mock.Calls))
+	}
+}
+
+func TestCreateSubIssues_LinkerSkippedWhenSourceRepoEmpty(t *testing.T) {
+	// When SourceRepo is empty, linker must NOT be called even if set.
+	fakeBin := t.TempDir()
+	script := filepath.Join(fakeBin, "gh")
+	err := os.WriteFile(script, []byte("#!/bin/sh\necho https://github.com/owner/testrepo/issues/7\n"), 0o755)
+	if err != nil {
+		t.Fatalf("write fake gh: %v", err)
+	}
+	origPATH := os.Getenv("PATH")
+	t.Setenv("PATH", fakeBin+string(filepath.ListSeparator)+origPATH)
+
+	mock := &mockSubIssueLinker{}
+	runner := NewRunner()
+	runner.SetSubIssueLinker(mock)
+
+	plan := &EpicPlan{
+		ParentTask: &Task{
+			ID: "GH-3",
+			// SourceRepo intentionally empty
+		},
+		Subtasks: []PlannedSubtask{
+			{Title: "Child", Description: "child", Order: 1},
+		},
+	}
+
+	ctx := context.Background()
+	_, _ = runner.CreateSubIssues(ctx, plan, t.TempDir())
+
+	if len(mock.Calls) != 0 {
+		t.Errorf("linker must not be called when SourceRepo is empty, got %d calls", len(mock.Calls))
+	}
+}

internal/executor/runner.go

@@ -281,6 +281,12 @@ type SubIssueCreator interface {
 	CreateIssue(ctx context.Context, parentID, title, body string, labels []string) (identifier string, url string, err error)
 }
 
+// SubIssueLinker links a child issue to a parent issue using GitHub's native sub-issue API (GH-2211).
+// *github.Client satisfies this interface via its LinkSubIssue method.
+type SubIssueLinker interface {
+	LinkSubIssue(ctx context.Context, owner, repo string, parentNum, childNum int) error
+}
+
 // Runner executes development tasks using an AI backend (Claude Code, OpenCode, etc.).
 // It manages task lifecycle including branch creation, AI invocation,
 // progress tracking, PR creation, and execution recording. Runner is safe for
@@ -329,6 +335,8 @@ type Runner struct {
 	worktreeManager       *WorktreeManager // Optional worktree manager with pool support
 	// GH-1471: SubIssueCreator for non-GitHub adapters
 	subIssueCreator       SubIssueCreator // Optional creator for sub-issues in external trackers
+	// GH-2211: SubIssueLinker for native GitHub sub-issue API linking
+	subIssueLinker        SubIssueLinker // Optional linker for native GitHub parent→child wiring
 	// GH-1599: Execution log store for milestone entries
 	logStore              *memory.Store // Optional log store for writing execution milestones
 	// GH-1811: Learning system (self-improvement)
@@ -629,6 +637,14 @@ func (r *Runner) SetSubIssueCreator(creator SubIssueCreator) {
 	r.subIssueCreator = creator
 }
 
+// SetSubIssueLinker sets the linker for native GitHub sub-issue linking (GH-2211).
+// When set, createSubIssuesViaGitHub will call LinkSubIssue after each child issue is
+// created to establish the native parent→child relationship. Failures are non-fatal
+// (warn-level log only) — the text "Parent: GH-N" body marker remains as fallback.
+func (r *Runner) SetSubIssueLinker(linker SubIssueLinker) {
+	r.subIssueLinker = linker
+}
+
 // SetIntentJudge sets the intent judge for diff-vs-ticket alignment verification (GH-624).
 func (r *Runner) SetIntentJudge(judge *IntentJudge) {
 	r.intentJudge = judge