feat(jobrunner): resolve dispatch target branch

Co-Authored-By: Virgil <virgil@lethean.io>

forge/testhelper_test.go

@@ -82,7 +82,8 @@ func newForgejoMux() *http.ServeMux {
 		}
 		jsonResponse(w, map[string]any{
 			"id": 10, "name": "org-repo", "full_name": "test-org/org-repo",
-			"owner": map[string]any{"login": "test-org"},
+			"owner":          map[string]any{"login": "test-org"},
+			"default_branch": "main",
 		})
 	})
 

jobrunner/handlers/dispatch.go

@@ -157,7 +157,7 @@ func (h *DispatchHandler) Execute(ctx context.Context, signal *jobrunner.Pipelin
 	}
 
 	// Build ticket.
-	targetBranch := "new" // TODO: resolve from epic or repo default
+	targetBranch := h.resolveTargetBranch(safeOwner, safeRepo)
 	ticketID := fmt.Sprintf("%s-%s-%d-%d", safeOwner, safeRepo, signal.ChildNumber, time.Now().Unix())
 
 	ticket := DispatchTicket{
@@ -263,6 +263,21 @@ func (h *DispatchHandler) Execute(ctx context.Context, signal *jobrunner.Pipelin
 	}, nil
 }
 
+func (h *DispatchHandler) resolveTargetBranch(owner, repo string) string {
+	const fallbackBranch = "main"
+
+	if h.forge == nil {
+		return fallbackBranch
+	}
+
+	repoInfo, err := h.forge.GetRepo(owner, repo)
+	if err != nil || repoInfo == nil || repoInfo.DefaultBranch == "" {
+		return fallbackBranch
+	}
+
+	return repoInfo.DefaultBranch
+}
+
 // failDispatch handles cleanup when dispatch fails (adds failed label, removes in-progress).
 func (h *DispatchHandler) failDispatch(signal *jobrunner.PipelineSignal, reason string) {
 	if failedLabel, err := h.forge.EnsureLabel(signal.RepoOwner, signal.RepoName, LabelAgentFailed, ColorAgentFailed); err == nil {

jobrunner/handlers/dispatch_test.go

@@ -175,7 +175,7 @@ func TestDispatch_TicketJSON_Good(t *testing.T) {
 		IssueNumber:  5,
 		IssueTitle:   "Fix the thing",
 		IssueBody:    "Please fix this bug",
-		TargetBranch: "new",
+		TargetBranch: "main",
 		EpicNumber:   3,
 		ForgeURL:     "https://forge.lthn.ai",
 		ForgeUser:    "darbs-claude",
@@ -198,7 +198,7 @@ func TestDispatch_TicketJSON_Good(t *testing.T) {
 	assert.Equal(t, float64(5), decoded["issue_number"])
 	assert.Equal(t, "Fix the thing", decoded["issue_title"])
 	assert.Equal(t, "Please fix this bug", decoded["issue_body"])
-	assert.Equal(t, "new", decoded["target_branch"])
+	assert.Equal(t, "main", decoded["target_branch"])
 	assert.Equal(t, float64(3), decoded["epic_number"])
 	assert.Equal(t, "https://forge.lthn.ai", decoded["forge_url"])
 	assert.Equal(t, "darbs-claude", decoded["forgejo_user"])
@@ -254,6 +254,30 @@ func TestDispatch_TicketJSON_Good_OmitsEmptyModelRunner_Good(t *testing.T) {
 	assert.False(t, hasRunner, "runner should be omitted when empty")
 }
 
+func TestDispatch_Execute_Good_UsesRepoDefaultBranch_Good(t *testing.T) {
+	srv := httptest.NewServer(withVersion(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	})))
+	defer srv.Close()
+
+	client := newTestForgeClient(t, srv.URL)
+	spinner := newTestSpinner(map[string]agentci.AgentConfig{
+		"darbs-claude": {Host: "claude@192.168.0.201", QueueDir: "~/ai-work/queue", Active: true},
+	})
+	h := NewDispatchHandler(client, srv.URL, "test-token", spinner)
+
+	sig := &jobrunner.PipelineSignal{
+		NeedsCoding: true,
+		Assignee:    "darbs-claude",
+		RepoOwner:   "test-org",
+		RepoName:    "org-repo",
+		ChildNumber: 1,
+	}
+
+	branch := h.resolveTargetBranch(sig.RepoOwner, sig.RepoName)
+	assert.Equal(t, "main", branch)
+}
+
 func TestDispatch_runRemote_Good_EscapesPath_Good(t *testing.T) {
 	outputPath := filepath.Join(t.TempDir(), "ssh-output.txt")
 	toolPath := writeFakeSSHCommand(t, outputPath)