fix(submit): check trunk transition before persisting new PR base

The `prActionUpdate` path in `executePRDecisions` was calling
`SetPRBase` before `maybeMarkPRReady`, which meant
`isTransitionToTrunk` always read the value we had just written
(trunk) and returned false. The publish-draft prompt was therefore
silently suppressed for all existing PRs transitioning to trunk.

Fix: call `maybeMarkPRReady` first, then persist the new base.
While here, move `GenerateAndPostStackComment` inside the success
branch so it doesn't run when `UpdatePRBase` fails.

Add `TestIsTransitionToTrunkOrderingInvariant` to document and
guard the required call order.

Author: boneskull

cmd/submit.go

@@ -468,15 +468,17 @@ func executePRDecisions(g *git.Git, cfg *config.Config, root *tree.Node, decisio
 					fmt.Printf("%s failed to update PR #%d base: %v\n", s.WarningIcon(), d.prNum, err)
 				} else {
 					fmt.Println(s.Success("ok"))
+					// Check for trunk transition BEFORE persisting the new base, so
+					// isTransitionToTrunk compares against the previous stored value.
+					maybeMarkPRReady(ghClient, cfg, d.prNum, b.Name, parent, trunk, s)
 					_ = cfg.SetPRBase(b.Name, parent) //nolint:errcheck // best effort — used for transition detection only
+					if err := ghClient.GenerateAndPostStackComment(root, b.Name, trunk, d.prNum, remoteBranches); err != nil {
+						fmt.Printf("%s failed to update stack comment for PR #%d: %v\n", s.WarningIcon(), d.prNum, err)
+					}
 					if opts.OpenWeb {
 						prURLs = append(prURLs, ghClient.PRURL(d.prNum))
 					}
 				}
-				if err := ghClient.GenerateAndPostStackComment(root, b.Name, trunk, d.prNum, remoteBranches); err != nil {
-					fmt.Printf("%s failed to update stack comment for PR #%d: %v\n", s.WarningIcon(), d.prNum, err)
-				}
-				maybeMarkPRReady(ghClient, cfg, d.prNum, b.Name, parent, trunk, s)
 			}
 		case prActionAdopt:
 			if opts.DryRun {

cmd/submit_internal_test.go

@@ -424,6 +424,41 @@ func TestIsTransitionToTrunk(t *testing.T) {
 	})
 }
 
+// TestIsTransitionToTrunkOrderingInvariant verifies the property that
+// isTransitionToTrunk must be evaluated BEFORE SetPRBase is called with trunk,
+// because SetPRBase overwrites the stored value that the function reads.
+// This guards against the regression where SetPRBase was called before
+// maybeMarkPRReady in the prActionUpdate path, silently suppressing the prompt.
+func TestIsTransitionToTrunkOrderingInvariant(t *testing.T) {
+	trunk := "main"
+
+	t.Run("returns_true_before_SetPRBase_when_parent_stored", func(t *testing.T) {
+		cfg := setupTestRepo(t)
+		if err := cfg.SetPRBase("feat-a", "feat-parent"); err != nil {
+			t.Fatalf("SetPRBase failed: %v", err)
+		}
+		// Simulates the correct ordering: check transition BEFORE persisting trunk.
+		transitionDetected := isTransitionToTrunk(cfg, "feat-a", trunk)
+		_ = cfg.SetPRBase("feat-a", trunk)
+		if !transitionDetected {
+			t.Error("expected transition to be detected when checked before SetPRBase(trunk)")
+		}
+	})
+
+	t.Run("returns_false_after_SetPRBase_wrong_order", func(t *testing.T) {
+		cfg := setupTestRepo(t)
+		if err := cfg.SetPRBase("feat-a", "feat-parent"); err != nil {
+			t.Fatalf("SetPRBase failed: %v", err)
+		}
+		// Simulates the buggy ordering: persist trunk BEFORE checking transition.
+		_ = cfg.SetPRBase("feat-a", trunk)
+		transitionDetected := isTransitionToTrunk(cfg, "feat-a", trunk)
+		if transitionDetected {
+			t.Error("demonstrates the bug: SetPRBase before check suppresses the prompt")
+		}
+	})
+}
+
 func TestApplyMustPushForSkippedAncestors(t *testing.T) {
 	main := &tree.Node{Name: "main"}
 	featA := &tree.Node{Name: "feat-a", Parent: main}