fix: harden legacy/tui3 non-tty flows and shutdown stability

src/main.py

@@ -1709,6 +1709,15 @@ def main(argv: list[str] | None = None, *, fingerprint: str | None = None) -> in
             print(colored(f"Error: Failed to restore backup: {e}", "red"))
             return 1
     elif args.command is None and not args.legacy_tui:
+        if not sys.stdin.isatty():
+            print(
+                colored(
+                    "Error: Interactive startup requires a TTY. "
+                    "Run in a terminal or use non-interactive subcommands.",
+                    "red",
+                )
+            )
+            return 1
         print("Startup Options:")
         print("1. Continue")
         print("2. Restore from backup")
@@ -1895,5 +1904,33 @@ def main(argv: list[str] | None = None, *, fingerprint: str | None = None) -> in
     return 0
 
 
+def _exit_as_main_process() -> "NoReturn":
+    """Execute ``main`` and terminate the process without Python finalizers.
+
+    In some runtime builds with native extensions, interpreter teardown can
+    intermittently raise SIGSEGV after the app has already completed a normal
+    shutdown path. Using ``os._exit`` here avoids that nondeterministic
+    interpreter-finalization crash while preserving the intended exit status.
+    """
+    exit_code = 0
+    try:
+        exit_code = int(main())
+    except SystemExit as exc:
+        code = exc.code
+        if isinstance(code, int):
+            exit_code = code
+        elif code is None:
+            exit_code = 0
+        else:
+            exit_code = 1
+    finally:
+        try:
+            sys.stdout.flush()
+            sys.stderr.flush()
+        except Exception:
+            pass
+    os._exit(exit_code)
+
+
 if __name__ == "__main__":
-    sys.exit(main())
+    _exit_as_main_process()

src/seedpass/cli/__init__.py

@@ -302,8 +302,21 @@ def tui2(
 
 
 @app.command("tui3")
-def tui3(ctx: typer.Context) -> None:
+def tui3(
+    ctx: typer.Context,
+    check: bool = typer.Option(
+        False,
+        "--check",
+        help="Check whether TUI v3 runtime dependencies are available",
+    ),
+) -> None:
     """Launch the experimental TUI v3 scratch architecture."""
+    if check:
+        from seedpass.tui_v3 import check_tui3_runtime
+
+        typer.echo(json.dumps(check_tui3_runtime(), indent=2, sort_keys=True))
+        return
+
     fingerprint = (ctx.obj or {}).get("fingerprint")
     services, preflight_error = _prime_tui2_service(ctx)
     if preflight_error is not None:

src/seedpass/core/manager.py

@@ -63,6 +63,7 @@ from utils.password_prompt import (
     prompt_existing_password,
     prompt_new_password,
     confirm_action,
+    PasswordPromptError,
 )
 from utils import masked_input, prompt_seed_words
 from utils.memory_protection import InMemorySecret
@@ -731,6 +732,10 @@ class PasswordManager:
                 )
                 print(colored("Q. Exit", "cyan"))
 
+                if not sys.stdin.isatty():
+                    raise SeedPassError(
+                        "Interactive seed profile selection requires a TTY"
+                    )
                 choice = input("Select a seed profile by number: ").strip()
                 if choice.lower() in {"q", "quit", "exit"}:
                     raise SeedPassError("Operation cancelled by user")
@@ -766,7 +771,14 @@ class PasswordManager:
                 current = self.fingerprint_manager.current_fingerprint
 
         except Exception as e:
-            logger.error(f"Error during seed profile selection: {e}", exc_info=True)
+            is_interactive_err = isinstance(e, (EOFError, PasswordPromptError)) or (
+                isinstance(e, SeedPassError) and "requires a TTY" in str(e)
+            )
+            logger.error(
+                "Error during seed profile selection: %s",
+                e,
+                exc_info=not is_interactive_err,
+            )
             print(colored(f"Error: Failed to select seed profile: {e}", "red"))
             raise SeedPassError(f"Failed to select seed profile: {e}") from e
 
@@ -1094,7 +1106,12 @@ class PasswordManager:
             except KeyboardInterrupt:
                 raise
             except Exception as e:
-                logger.error(f"Failed to set up EncryptionManager: {e}", exc_info=True)
+                is_interactive_err = isinstance(e, (EOFError, PasswordPromptError))
+                logger.error(
+                    "Failed to set up EncryptionManager: %s",
+                    e,
+                    exc_info=not is_interactive_err,
+                )
                 print(colored(f"Error: Failed to set up encryption: {e}", "red"))
                 if exit_on_fail:
                     raise SeedPassError(f"Failed to set up encryption: {e}") from e

src/tests/test_password_prompt.py

@@ -28,6 +28,16 @@ def test_prompt_existing_password(monkeypatch):
     assert password_prompt.prompt_existing_password() == "mypassword"
 
 
+def test_prompt_existing_password_non_tty(monkeypatch):
+    monkeypatch.setattr(
+        password_prompt,
+        "masked_input",
+        lambda _prompt: (_ for _ in ()).throw(EOFError("no tty")),
+    )
+    with pytest.raises(password_prompt.PasswordPromptError, match="requires a TTY"):
+        password_prompt.prompt_existing_password()
+
+
 def test_confirm_action_yes_no(monkeypatch):
     monkeypatch.setattr(builtins, "input", lambda _: "Y")
     assert password_prompt.confirm_action()

src/tests/test_seed_prompt.py

@@ -5,6 +5,7 @@ from utils import seed_prompt
 
 def test_masked_input_posix_backspace(monkeypatch, capsys):
     seq = iter(["a", "b", "\x7f", "c", "\n"])
+    monkeypatch.setattr(seed_prompt.sys.stdin, "isatty", lambda: True)
     monkeypatch.setattr(seed_prompt.sys.stdin, "read", lambda n=1: next(seq))
     monkeypatch.setattr(seed_prompt.sys.stdin, "fileno", lambda: 0)
 
@@ -36,6 +37,7 @@ def test_masked_input_posix_backspace(monkeypatch, capsys):
 
 def test_masked_input_windows_space(monkeypatch, capsys):
     seq = iter(["x", "y", " ", "z", "\r"])
+    monkeypatch.setattr(seed_prompt.sys.stdin, "isatty", lambda: True)
     fake_msvcrt = types.SimpleNamespace(getwch=lambda: next(seq))
     monkeypatch.setattr(seed_prompt, "msvcrt", fake_msvcrt)
     monkeypatch.setattr(seed_prompt.sys, "platform", "win32", raising=False)
@@ -49,6 +51,7 @@ def test_masked_input_windows_space(monkeypatch, capsys):
 
 def test_masked_input_posix_ctrl_c(monkeypatch):
     seq = iter(["\x03"])
+    monkeypatch.setattr(seed_prompt.sys.stdin, "isatty", lambda: True)
     monkeypatch.setattr(seed_prompt.sys.stdin, "read", lambda n=1: next(seq))
     monkeypatch.setattr(seed_prompt.sys.stdin, "fileno", lambda: 0)
 
@@ -70,6 +73,7 @@ def test_masked_input_posix_ctrl_c(monkeypatch):
 
 def test_masked_input_windows_ctrl_c(monkeypatch):
     seq = iter(["\x03"])
+    monkeypatch.setattr(seed_prompt.sys.stdin, "isatty", lambda: True)
     fake_msvcrt = types.SimpleNamespace(getwch=lambda: next(seq))
     monkeypatch.setattr(seed_prompt, "msvcrt", fake_msvcrt)
     monkeypatch.setattr(seed_prompt.sys, "platform", "win32", raising=False)
@@ -93,6 +97,12 @@ def test_prompt_seed_words_valid(monkeypatch):
     assert result == phrase
 
 
+def test_masked_input_requires_tty(monkeypatch):
+    monkeypatch.setattr(seed_prompt.sys.stdin, "isatty", lambda: False)
+    with pytest.raises(EOFError, match="requires a TTY"):
+        seed_prompt.masked_input("Enter: ")
+
+
 def test_prompt_seed_words_invalid_word(monkeypatch):
     from mnemonic import Mnemonic
 

src/tests/test_typer_cli.py

@@ -1092,6 +1092,18 @@ def test_tui2_check(monkeypatch):
     assert payload["textual_available"] is True
 
 
+def test_tui3_check(monkeypatch):
+    monkeypatch.setattr(
+        cli,
+        "check_tui2_runtime",
+        lambda: {"status": "ok", "backend": "textual", "textual_available": True},
+    )
+    result = runner.invoke(app, ["tui3", "--check"])
+    assert result.exit_code == 0
+    payload = json.loads(result.stdout)
+    assert "textual_available" in payload
+
+
 def test_tui2_unavailable_without_fallback(monkeypatch):
     monkeypatch.setattr(cli, "_get_entry_service", lambda _ctx: object())
     monkeypatch.setattr(cli, "launch_tui2", lambda **_: False)

src/utils/password_prompt.py

@@ -142,6 +142,8 @@ def prompt_new_password(max_retries: int | None = None) -> str:
             print(colored("\nOperation cancelled by user.", "yellow"))
             logging.info("Password prompt interrupted by user.")
             raise PasswordPromptError("Operation cancelled by user")
+        except EOFError:
+            raise PasswordPromptError("Interactive password prompt requires a TTY")
         except Exception as e:
             logging.error(
                 f"Unexpected error during password prompt: {e}", exc_info=True
@@ -204,6 +206,8 @@ def prompt_existing_password(
             print(colored("\nOperation cancelled by user.", "yellow"))
             logging.info("Existing password prompt interrupted by user.")
             raise PasswordPromptError("Operation cancelled by user")
+        except EOFError:
+            raise PasswordPromptError("Interactive password prompt requires a TTY")
         except Exception as e:
             logging.error(
                 f"Unexpected error during existing password prompt: {e}",

src/utils/seed_prompt.py

@@ -106,6 +106,8 @@ def _masked_input_posix(prompt: str) -> str:
 
 def masked_input(prompt: str) -> str:
     """Return input from the user while masking typed characters."""
+    if not sys.stdin.isatty():
+        raise EOFError("Interactive input requires a TTY")
     func = _masked_input_windows if sys.platform == "win32" else _masked_input_posix
     pause_console_logging()
     try: