Close diagnostic and restore coverage gaps

internal/app/restore_execution_test.go

@@ -357,7 +357,7 @@ func TestExecuteRestoreLockConflictFailsAndWritesNothing(t *testing.T) {
 	}
 }
 
-func TestExecuteRestoreInvalidManifestDoesNotCorruptExistingManifest(t *testing.T) {
+func TestExecuteRestorePlanInvalidManifestDoesNotCorruptExistingManifest(t *testing.T) {
 	cfg := restorePlanConfig(t)
 	store := &storage.FakeBackend{}
 	current := seedCommittedRestoreSnapshot(t, cfg, store, "20260519T010203Z-a1b2c3d4", map[string][]byte{
@@ -417,6 +417,87 @@ func TestExecuteRestoreInvalidManifestDoesNotCorruptExistingManifest(t *testing.
 	}
 }
 
+func TestExecuteRestoreInvalidManifestReportsFailureAndRetainsRecoveryMarker(t *testing.T) {
+	workspaceRoot := t.TempDir()
+	pipelinePath, campaignPath, sessionPath := writeValidConfigFiles(t, workspaceRoot)
+	cfg, err := config.LoadWithSessionOptions(pipelinePath, campaignPath, sessionPath, config.SessionLoadOptions{})
+	if err != nil {
+		t.Fatalf("LoadWithSessionOptions() error = %v", err)
+	}
+	store := &storage.FakeBackend{}
+	seedCommittedRestoreSnapshot(t, cfg, store, "20260519T010203Z-a1b2c3d4", map[string][]byte{
+		"transcripts/full.json": []byte("remote-transcript"),
+	})
+
+	sessionRoot := artifacts.SessionWorkDirForCampaign(workspaceRoot, cfg.Session.Campaign, cfg.Session.SessionID)
+	existing := manifest.New(cfg.Session.SessionID, nowUTC())
+	existing.Campaign = cfg.Session.Campaign
+	existingPath := filepath.Join(sessionRoot, "manifest.json")
+	manifestStore := &manifest.LocalStore{}
+	if err := manifestStore.Save(context.Background(), existingPath, existing); err != nil {
+		t.Fatalf("save existing local manifest: %v", err)
+	}
+	existingData, err := os.ReadFile(existingPath)
+	if err != nil {
+		t.Fatalf("read existing local manifest: %v", err)
+	}
+
+	restoreWithStoreAndRealPhases(t, store)
+	realBuildRestorePlan := buildRestorePlanFn
+	buildRestorePlanFn = func(ctx context.Context, cfg *config.Config, current *RemoteCurrentState, objectStore storage.ObjectStore, opts RestorePlanOptions) (*RestorePlan, error) {
+		plan, err := realBuildRestorePlan(ctx, cfg, current, objectStore, opts)
+		if err != nil {
+			return nil, err
+		}
+		invalidManifest := []byte("{invalid json")
+		for index := range plan.Actions {
+			if plan.Actions[index].LocalRelativePath != config.PathManifestFile {
+				continue
+			}
+			plan.Actions[index].VerifiedContent = invalidManifest
+			plan.Actions[index].SHA256 = restoreCommitSHA256(invalidManifest)
+			plan.Actions[index].Size = int64(len(invalidManifest))
+			store.SeedObject(storage.FakeObject{
+				Key:  plan.Actions[index].RemoteKey,
+				Data: invalidManifest,
+				ETag: plan.Actions[index].Generation,
+			})
+			return plan, nil
+		}
+		t.Fatal("restore plan has no manifest action")
+		return nil, nil
+	}
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := Execute([]string{"session", "restore", cfg.Session.SessionID, "--config", pipelinePath, "--campaign-file", campaignPath, "--session", sessionPath, "--force"}, &stdout, &stderr)
+	if code == 0 {
+		t.Fatal("exit code = 0, want non-zero")
+	}
+	if !strings.Contains(stderr.String(), "validate manifest decode") {
+		t.Fatalf("stderr = %q, want manifest validation failure", stderr.String())
+	}
+	mustReadEquals(t, filepath.Join(sessionRoot, "transcripts", "full.json"), "remote-transcript")
+	report := mustReadRestoreReport(t, filepath.Join(sessionRoot, "reports", "restore-latest.json"))
+	if report.Status != "failed" {
+		t.Fatalf("report status = %q, want failed", report.Status)
+	}
+	if strings.TrimSpace(report.Error) == "" {
+		t.Fatal("report error is empty, want failure context")
+	}
+	afterData, err := os.ReadFile(existingPath)
+	if err != nil {
+		t.Fatalf("read local manifest after failure: %v", err)
+	}
+	if string(afterData) != string(existingData) {
+		t.Fatalf("local manifest changed after failed restore; before=%q after=%q", string(existingData), string(afterData))
+	}
+	markerPath := artifacts.SessionRestoreMarkerPathForCampaign(workspaceRoot, cfg.Session.Campaign, cfg.Session.SessionID)
+	if _, err := os.Stat(markerPath); err != nil {
+		t.Fatalf("incomplete restore marker should remain after failed forced restore: %v", err)
+	}
+}
+
 func TestExecuteRestorePlanPathMismatchFails(t *testing.T) {
 	cfg := restorePlanConfig(t)
 	current := restorePlanCurrentState(t, cfg)