fix: close an idle error screen with its code

An idle close exited 0 on every screen, an error one too. It now exits with the error's or the result's code and prints that screen's words after the idle line.

install.py

@@ -12941,9 +12941,27 @@ def tui_farewell(state: TuiState) -> list[str]:
     return [screen_text(line) for line in _farewell_lines(state)]
 
 
+def tui_idle_code(state: TuiState) -> int:
+    """The exit code of an idle close: an error's or a result's on those
+    screens, so a launcher tells them from a close with nothing to say."""
+    if state.screen == "error":
+        return state.error_code
+    if state.screen == "result" and state.code is not None:
+        return state.code
+    return 0
+
+
 def _farewell_lines(state: TuiState) -> list[str]:
-    if state.idle_closed:
-        return [f"RetroBIOS: {TUI_IDLE_WORDS}"]
+    if not state.idle_closed:
+        return _closing_lines(state)
+    idle = f"RetroBIOS: {TUI_IDLE_WORDS}"
+    # What an error or a result screen said stays said.
+    if state.screen in ("error", "result"):
+        return [idle, *_closing_lines(state)]
+    return [idle]
+
+
+def _closing_lines(state: TuiState) -> list[str]:
     if state.screen != "result" and state.download is not None:
         # An install ran: what it wrote is said, whatever ended it.
         title, lines = tui_outcome(state)
@@ -13114,7 +13132,7 @@ def run_tui(args: argparse.Namespace) -> int:
                 quiet_since = time.monotonic()
             elif (idle is not None and not pressed and state.exit_code is None
                     and time.monotonic() - quiet_since >= idle):
-                state.idle_closed, state.exit_code = True, 0
+                state.idle_closed, state.exit_code = True, tui_idle_code(state)
             if flags["interrupt"]:
                 flags["interrupt"] = False
                 if time.monotonic() >= ignore_interrupt_until[0]:

tests/test_install_tui.py

@@ -2595,6 +2595,60 @@ class IdleExit(unittest.TestCase):
         self.assertEqual(install.tui_farewell(state),
                          ["RetroBIOS: No button pressed, closing."])
 
+    def test_an_error_screen_closes_with_its_code(self):
+        """Closed idle on "No internet: offline mode", the launcher read 0
+        and showed nothing."""
+        state = fresh_state()
+        state.stack = ["setup", "checking"]
+        install._fail(state, ["Give the file list with --manifest FILE."], 1)
+        state.error_title = "No internet: offline mode"
+        self.assertEqual(self.idle_close(state), 1)
+        self.assertEqual(install.tui_farewell(state), [
+            "RetroBIOS: No button pressed, closing.",
+            "RetroBIOS: No internet: offline mode",
+            "Give the file list with --manifest FILE."])
+
+    def test_a_result_closes_with_the_install_code(self):
+        state = fresh_state()
+        state.stack = ["setup", "result"]
+        state.code = 2
+        state.summary = {"event": "summary", "mode": "install", "installed": 1,
+                         "up_to_date": 0, "pending": 0,
+                         "failed": [{"dest": "a.bin", "reason": "disk full"}],
+                         "skipped": [], "left_out": [], "kept": [], "interrupted": False}
+        state.dest = SYSTEM_DIR
+        self.assertEqual(self.idle_close(state), 2)
+        farewell = install.tui_farewell(state)
+        self.assertEqual(farewell[:2], ["RetroBIOS: No button pressed, closing.",
+                                        "RetroBIOS: Finished with errors"])
+
+    def test_any_other_screen_closes_with_0(self):
+        state = fresh_state()
+        state.stack = ["setup"]
+        self.assertEqual(self.idle_close(state), 0)
+
+    def idle_close(self, state: install.TuiState) -> int:
+        """run_tui on state, no key ever pressed, closed by the idle timer."""
+        class Quiet(Crash.FakeTerminal):
+            def keys(self, timeout):
+                time.sleep(0.01)
+                return []
+
+        out = io.StringIO()
+        work = Path(tempfile.mkdtemp(dir=REPO_ROOT / "tmp"))
+        self.addCleanup(shutil.rmtree, work, True)
+        with mock.patch.object(install, "_TuiTerminal", Quiet), \
+                mock.patch.object(install.tempfile, "mkdtemp", return_value=str(work)), \
+                mock.patch.object(install, "tui_start", return_value=(state, [])), \
+                mock.patch.object(install, "_open_local_sources"), \
+                mock.patch.object(install, "detect_os", return_value="linux"), \
+                mock.patch.dict(os.environ, {install.TUI_IDLE_ENV: "0.05"}), \
+                mock.patch.object(sys, "stdout", out), mock.patch.object(sys, "stderr", out):
+            code = install.run_tui(_args())
+        self.assertTrue(state.idle_closed)
+        self.assertIn("No button pressed, closing.", out.getvalue())
+        return code
+
 
 class AReadErrorIsNotAClosedWindow(unittest.TestCase):
     """Any EIO read as the window closing: a failing SD card answers EIO

wiki/installer.md

@@ -1087,6 +1087,9 @@ A launcher with no mapper at all (a keyboard) leaves it unset.
 A launcher can also set `RETROBIOS_IDLE_EXIT` to a number of seconds: when
 no button has reached the interface since it opened, and nothing has run for
 that long, it closes with `No button pressed, closing.` and exit status 0.
+Closed on an error or a result screen, it prints that screen's words after
+the line and exits with its code (1 for `No internet: offline mode`), so
+the launcher can tell an error from a close with nothing to report.
 The time counts from the end of the last check, so a launcher that names the
 platform, whose interface moves on to the plan by itself, closes the same way.
 A mapper that never opened the pad would otherwise hold the device on that
@@ -1341,7 +1344,7 @@ RetroArch folder that holds only `scph5501.bin`, in the order written:
 | `SSL_CERT_FILE`, `SSL_CERT_DIR` | The trusted certificates to check servers with, for a Python that finds none of its own |
 | `RETROBIOS_PLAIN`, `ACCESSIBLE` | Set to anything but `0`: the questions come line by line, as with `--plain`, instead of the full-screen interface |
 | `RETROBIOS_PAD` | The buttons a handheld launcher's mapper sends to the full screen (`gptokeyb`, `gptokeyb_muxterm`, `muxterm`, `evmapy`, `miyoo`), so its hints name them. See [On a handheld](#on-a-handheld-the-retrobios-port) |
-| `RETROBIOS_IDLE_EXIT` | Seconds the full screen waits for a first button, counted while nothing runs. With none pressed, it closes with exit status 0 |
+| `RETROBIOS_IDLE_EXIT` | Seconds the full screen waits for a first button, counted while nothing runs. With none pressed, it closes with exit status 0, or with the code of the error or result screen it closed on |
 | `HTTPS_PROXY`, `NO_PROXY` | Honoured for every download through the standard library's default proxy handling: one names the proxy, the other the hosts to reach directly |
 
 ## When something goes wrong