feat: no console drop when uninstalling backends

6 files changed, 67 insertions, 20 deletions

diff --git a/app/backends/__init__.py b/app/backends/__init__.py
index 83f9866..63f0709 100644
--- a/app/backends/__init__.py
+++ b/app/backends/__init__.py
@@ -147,13 +147,16 @@ class BackendInfo:
 
     SETUP_SCREEN runs the setup wizard on an already-open curses screen
     (the hub's), returning 0 on completion and non-zero when aborted; the
-    hub calls it as one screen of its own ``tui.Wizard`` stack.
+    hub calls it as one screen of its own ``tui.Wizard`` stack. UNINSTALL
+    removes the backend (stops its servers, pip-uninstalls, deletes its
+    files); the hub runs it inside the task view, calling it with optional
+    ``emit``/``cancel`` keywords (cancel honored between phases only).
     """
     key: str
     label: str
     detect: Callable[[], BackendStatus]
     setup_screen: Callable[[object], int]
-    uninstall: Callable[[], int] = lambda: 0
+    uninstall: Callable[..., int] = lambda *args, **kwargs: 0
 
 
 REGISTRY: List[BackendInfo] = []
diff --git a/app/backends/audiocpp.py b/app/backends/audiocpp.py
index 0feb480..31aa01d 100755
--- a/app/backends/audiocpp.py
+++ b/app/backends/audiocpp.py
@@ -1650,16 +1650,25 @@ def delete_model_files(server_json: Path, entries: List[dict]) -> int:
     return removed
 
 
-def uninstall() -> int:
+def uninstall(*, emit=None, cancel=None) -> int:
     """Remove the audio.cpp backend entirely: stop its server, delete the checkout.
 
     The checkout (``app/audio.cpp``, or wherever ``find_local_checkout``
     resolves it) holds the built binary, the downloaded models, and the
     server.json, so removing the directory uninstalls the backend. A running
-    server this tool started is stopped first (best-effort). Returns the exit
-    code.
+    server this tool started is stopped first (best-effort).
+
+    EMIT is accepted for registry symmetry with the other backends but is
+    unused here — this uninstall has no subprocess phase, and its prints are
+    captured by the task view when run in the TUI. CANCEL is a
+    ``threading.Event`` honored between phases only (after the server has
+    been stopped, before the checkout is deleted), so a started phase always
+    completes and the uninstall never tears halfway. Returns the exit code
+    (130 when cancelled before a remaining phase).
     """
     servers.stop("audiocpp")
+    if common.cancel_requested(cancel):
+        return 130
     checkout = find_local_checkout()
     if checkout is None:
         print("[INFO] No audio.cpp checkout to remove.")
diff --git a/app/backends/common.py b/app/backends/common.py
index cb573c3..10b4ccf 100644
--- a/app/backends/common.py
+++ b/app/backends/common.py
@@ -71,6 +71,18 @@ def drain_post_tui_notices() -> List[str]:
     return notices
 
 
+def cancel_requested(cancel) -> bool:
+    """True when CANCEL (a ``threading.Event``) is given and set.
+
+    Shared guard for the multi-phase uninstall actions: cancellation is
+    honored only between phases (stop servers / pip / delete files), so a
+    phase that already started always runs to completion and an uninstall
+    never tears halfway. Callers return 130 when this fires before a
+    pending phase.
+    """
+    return cancel is not None and cancel.is_set()
+
+
 def normalize_dir_arg(value: str) -> Path:
     """Normalize a user-supplied path argument.
 
@@ -301,8 +313,7 @@ def run_console_subprocess(argv: List[str], cwd: Optional[Path] = None,
     """Run a subprocess, streaming output to the console or to EMIT.
 
     With EMIT None the child inherits the real terminal and its output
-    appears normally (used by the non-interactive CLI paths and the quick
-    ``tui.suspend`` actions like uninstall). With EMIT given (a
+    appears normally (the non-interactive CLI paths). With EMIT given (a
     ``callable(str)``) the child's stdout/stderr are merged, read line by
     line (splitting on both ``\\n`` and ``\\r`` so carriage-return progress
     updates like git's or tqdm's surface as lines), and each line is passed
@@ -459,11 +470,13 @@ def pip_install(packages: List[str]) -> int:
     return envs.pip_install(packages)
 
 
-def pip_uninstall(packages: List[str]) -> int:
+def pip_uninstall(packages: List[str], *, emit=None) -> int:
     """pip uninstall PACKAGES from the managed venv. Returns exit code.
 
     Delegates to ``backends.envs.pip_uninstall`` (local import to avoid a
-    circular import). Used by the backends' ``uninstall`` action.
+    circular import). Used by the backends' ``uninstall`` action. With EMIT
+    given (the in-TUI task view) pip runs piped, streaming into EMIT, so
+    its output never touches the terminal behind curses.
     """
     from backends import envs
-    return envs.pip_uninstall(packages)
+    return envs.pip_uninstall(packages, emit=emit)
diff --git a/app/backends/envs.py b/app/backends/envs.py
index 7b3c54b..cfeeec6 100644
--- a/app/backends/envs.py
+++ b/app/backends/envs.py
@@ -113,18 +113,21 @@ def pip_install(packages: List[str], *, emit=None, cancel=None) -> int:
     return common.run_console_subprocess(argv, emit=emit, cancel=cancel)
 
 
-def pip_uninstall(packages: List[str]) -> int:
+def pip_uninstall(packages: List[str], *, emit=None) -> int:
     """pip uninstall PACKAGES from the venv. Returns pip's exit code.
 
     Used by the backends' ``uninstall`` action to remove pip-installed TTS
     packages from the managed environment. A missing env is a no-op (there
-    is nothing to uninstall from), reported as success.
+    is nothing to uninstall from), reported as success. With EMIT given
+    (the in-TUI task view) pip runs with its output piped and streamed to
+    EMIT, so nothing writes to the terminal behind curses.
     """
     if not env_exists():
         return 0
     print(f"[INFO] pip uninstall {' '.join(packages)} from {ENV_DIR}...")
     return common.run_console_subprocess(
-        [str(env_python()), "-m", "pip", "uninstall", "-y", *packages])
+        [str(env_python()), "-m", "pip", "uninstall", "-y", *packages],
+        emit=emit)
 
 
 def module_available(module: str) -> bool:
diff --git a/app/backends/faster.py b/app/backends/faster.py
index 585e480..8c64183 100755
--- a/app/backends/faster.py
+++ b/app/backends/faster.py
@@ -591,21 +591,32 @@ def _detect_remote(managed: bool = False):
     return False, {}
 
 
-def uninstall() -> int:
+def uninstall(*, emit=None, cancel=None) -> int:
     """Remove the faster-qwen3-tts backend entirely.
 
     Uninstalls the pip package (``faster-qwen3-tts``) from the managed venv
     and deletes the cloned checkout (``app/faster-qwen3-tts``, which holds
     examples/openai_server.py and voices.json). A running server this tool
-    started is stopped first (best-effort). Returns the exit code.
+    started is stopped first (best-effort).
+
+    With EMIT given (the in-TUI task view) pip runs piped, streaming into
+    EMIT, so its output never touches the terminal behind curses. CANCEL is
+    a ``threading.Event`` honored between phases only (stop server / pip /
+    delete checkout) — a started phase always completes, so pip is never
+    killed mid-run. Returns the exit code (130 when cancelled before a
+    remaining phase).
     """
     servers.stop("faster")
-    rc = common.pip_uninstall(["faster-qwen3-tts"])
+    if common.cancel_requested(cancel):
+        return 130
+    rc = common.pip_uninstall(["faster-qwen3-tts"], emit=emit)
     if rc != 0:
         print("[WARNING] pip uninstall failed (exit "
               f"{rc}); remove faster-qwen3-tts from the managed venv manually")
     else:
         print("[OK] faster-qwen3-tts removed.")
+    if common.cancel_requested(cancel):
+        return 130
     checkout = _checkout()
     if checkout.is_dir():
         print(f"[INFO] Removing checkout {checkout}...")
diff --git a/app/backends/qwen.py b/app/backends/qwen.py
index be7ebfe..c6a11bf 100644
--- a/app/backends/qwen.py
+++ b/app/backends/qwen.py
@@ -354,17 +354,25 @@ def _detect_remote(managed: bool = False):
     return remote_models, remote_urls
 
 
-def uninstall() -> int:
+def uninstall(*, emit=None, cancel=None) -> int:
     """Remove the qwen-tts backend entirely: stop its servers, pip uninstall.
 
     qwen-tts is a pip package (``qwen_tts`` + the ``qwen-tts-demo`` script)
     installed into the managed venv, so uninstalling it removes the backend.
-    Any server this tool started is stopped first (best-effort). Returns the
-    exit code.
+    Any server this tool started is stopped first (best-effort).
+
+    With EMIT given (the in-TUI task view) pip runs piped, streaming into
+    EMIT, so its output never touches the terminal behind curses. CANCEL is
+    a ``threading.Event`` honored between phases only (after the servers
+    have been stopped, before pip starts) — a started phase always completes,
+    so pip is never killed mid-run. Returns the exit code (130 when
+    cancelled before pip ran).
     """
     servers.stop("qwen-custom")
     servers.stop("qwen-clone")
-    rc = common.pip_uninstall([QWEN_PIP_PKG])
+    if common.cancel_requested(cancel):
+        return 130
+    rc = common.pip_uninstall([QWEN_PIP_PKG], emit=emit)
     if rc != 0:
         print(f"[WARNING] pip uninstall failed (exit {rc}); remove "
               f"{QWEN_PIP_PKG} from the managed venv manually")