# NousResearch/hermes-agent · hermes update command crashes and corrupts state

## Open now

- Nothing open on GitHub.

Multiple bugs and fixes related to the 'hermes update' command failing with errors (including a ValueError unpack crash), leaving installations in a broken or half-updated state with no clean recovery path. Work addresses crash prevention, subprocess isolation, venv handling, and stuck-state markers.

## TL;DR

- 9 member(s): 0 open issue(s), 2 closed issue(s), 0 open PR(s), 2 merged PR(s), 5 PR(s) closed without merging.
- A fix was merged to main in PR #39780. Verify it addresses your case.
- **Recommended:** read PR #39780 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `unresolved`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.23`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #39549: Bug: \`hermes update\` aborts with \`ValueError: too many values to unpack (expected 2)\` in \`_build_web_ui\`; leaves installation in half-updated state with no way to retry
- #39706: hermes update crashes with \`ValueError: too many values to unpack (expected 2)\` during post-pull dependency install

## Prior & competing PRs

- **#39780: fix(update): make ensure_uv() survive the update boundary (no first-run crash)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`; implication `superseded`
  - files: `hermes_cli/managed_uv.py`, `tests/hermes_cli/test_managed_uv.py`
  - fix hunks:
  - `hermes_cli/managed_uv.py`

    ```diff
    @@ -51,15 +51,54 @@ def resolve_uv() -> Optional[str]:
         return None
     
     
    -def ensure_uv() -> Optional[str]:
    +class _UvResult(str):
    +    """``ensure_uv()`` return value that survives an update boundary.
    +
    +    ``ensure_uv()``'s arity has flipped between a single path string and a
    +    ``(path, fresh_bootstrap)`` tuple across releases. ``hermes update`` runs
    +    the call site from the *old*, already-imported ``hermes_cli.main`` against
    +    this *freshly pulled* module, so the two can disagree on how many values
    +    ``ensure_uv()`` returns. An install parked on a 2-tuple release runs
    +    ``uv_bin, fresh_bootstrap = ensure_uv()`` against the single-value module
    +    and crashes the first update: the returned path is a plain ``str``, which is
    +    itself iterable, so the 2-target unpack walks its characters and raises
    +    ``ValueError: too many values to unpack (expected 2)`` (and on the failure
    +    path the ``None`` return raises ``TypeError: cannot unpack non-iterable
    +    NoneType``). This wrapper answers to both conventions:
    +
    +        uv_bin = ensure_uv()         # behaves as the path str ("" when absent)
    +        uv_bin, fresh = ensure_uv()  # unpacks as (path|None, fresh_bootstrap)
    +
    +    Missing uv is the empty string (falsy) instead of ``None`` so legacy
    +    2-target call sites can still unpack a failure without raising, while
    +    ``if not uv_bin`` keeps working for single-value callers.
    +    """
    +
    +    fresh_bootstrap: bool
    +
    +    def __new__(cls, path: Optional[str], fresh: bool = False) -> "_UvResult":
    +        self = super().__new__(cls, path or "")
    +        self.fresh_bootstrap = fresh
    +        return self
    +
    +    def __iter__(self):
    +        # Tuple-unpacking hook for legacy ``uv_bin, fresh = ensure_uv()`` sites.
    +        # First element mirrors the historical contract: the path string, or
    +        # ``None`` when uv is unavailable.
    +        return iter(((str(self) or None), self.fresh_bootstrap))
    +
    +
    +def ensure_uv() -> "_UvResult":
         """Return the managed uv path, installing it first if necessary.
     
    -    On failure returns ``None`` (never raises) so callers can fall
    -    back to pip gracefully.
    +    Returns a :class:`_UvResult` (a ``str`` subclass) that is both usable
    +    directly as the path and unpackable as ``(path, fresh_bootstrap)`` for
    +    older call sites. On failure the result is falsy (``""``) — never raises —
    +    so callers can fall back to pip gracefully.
         """
         existing = resolve_uv()
         if existing:
    -        return existing
    +        return _UvResult(existing)
     
         target = managed_uv_path()
         target.parent.mkdir(parents=True, exist_ok=True)
    ```

    ```diff
    @@ -71,7 +110,7 @@ def ensure_uv() -> Optional[str]:
         except Exception as exc:
             logger.warning("Managed uv install failed: %s", exc)
             print(f"  ✗ Failed to install managed uv: {exc}")
    -        return None
    +        return _UvResult(None)
     
         # Verify
         result = resolve_uv()
    ```

    ```diff
    @@ -85,7 +124,7 @@ def ensure_uv() -> Optional[str]:
             print(f"  ✓ Managed uv installed ({version})")
         else:
             print("  ✗ Managed uv install appeared to succeed but binary not found")
    -    return result
    +    return _UvResult(result)
     
     
     def update_managed_uv() -> Optional[str]:
    ```
  - `tests/hermes_cli/test_managed_uv.py`

    ```diff
    @@ -92,12 +92,55 @@ def fake_install(target):
                 assert path == str(tmp_path / "bin" / "uv")
                 mock_install.assert_called_once()
     
    -    def test_install_failure_returns_none(self, tmp_path):
    +    def test_install_failure_returns_falsy(self, tmp_path):
             with patch("hermes_cli.managed_uv.get_hermes_home", return_value=tmp_path), \
                  patch("hermes_cli.managed_uv._install_uv", side_effect=RuntimeError("network down")):
                 from hermes_cli.managed_uv import ensure_uv
                 path = ensure_uv()
    -            assert path is None
    +            # Failure is a falsy sentinel (not None) so legacy 2-target call
    +            # sites can still unpack it without raising — see
    +            # TestEnsureUvUpdateBoundary for why.
    +            assert not path
    +
    +
    +class TestEnsureUvUpdateBoundary:
    +    """``ensure_uv()`` must answer to both the single-value and the legacy
    +    ``(path, fresh_bootstrap)`` call conventions.
    +
    +    ``hermes update`` runs the call site from the old, already-imported
    +    ``hermes_cli.main`` against the freshly pulled ``managed_uv``. A release
    +    parked on a ``(path, fresh)`` tuple runs ``uv_bin, fresh = ensure_uv()``
    +    against the single-value module; the path is an iterable ``str`` so the
    +    2-target unpack walked its characters and raised
    +    ``ValueError: too many values to unpack (expected 2)`` (root cause behind
    +    PR #39763), or ``TypeError`` on the ``None`` failure path. The result must
    +    therefore be usable as a bare path *and* unpackable as a 2-tuple, in both
    +    the success and failure cases.
    +    """
    +
    +    def test_success_usable_as_single_value(self, tmp_path):
    +        _make_executable(tmp_path / "bin" / "uv")
    +        with patch("hermes_cli.managed_uv.get_hermes_home", return_value=tmp_path):
    +            from hermes_cli.managed_uv import ensure_uv
    +            uv_bin = ensure_uv()
    +            assert uv_bin == str(tmp_path / "bin" / "uv")
    +            assert bool(uv_bin) is True
    +
    +    def test_success_unpacks_as_legacy_two_tuple(self, tmp_path):
    +        _make_executable(tmp_path / "bin" / "uv")
    +        with patch("hermes_cli.managed_uv.get_hermes_home", return_value=tmp_path):
    +            from hermes_cli.managed_uv import ensure_uv
    +            uv_bin, fresh = ensure_uv()  # old: uv_bin, fresh_bootstrap = ensure_uv()
    +            assert uv_bin == str(tmp_path / "bin" / "uv")
    +            assert fresh is False
    +
    +    def test_failure_unpacks_without_raising(self, tmp_path):
    +        with patch("hermes_cli.managed_uv.get_hermes_home", return_value=tmp_path), \
    +             patch("hermes_cli.managed_uv._install_uv", side_effect=RuntimeError("network down")):
    +            from hermes_cli.managed_uv import ensure_uv
    +            uv_bin, fresh = ensure_uv()
    +            assert uv_bin is None
    +            assert fresh is False
     
     
     # ---------------------------------------------------------------------------
    ```
- **#40191: fix(cli): repair hermes update path (venv detection, uv arity, v25→v26 migration)**. closed without merge · fix tier `suggested`
  - maintainer direction: category `uncategorized`; implication `needs_llm`
- **#42172: fix(update): self-heal a venv left half-built by an interrupted install**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`; implication `superseded`
  - files: `.gitignore`, `hermes_cli/main.py`, `tests/hermes_cli/test_update_interrupted_recovery.py`
  - fix hunks:
  - `.gitignore`

    ```diff
    @@ -114,6 +114,12 @@ docs/superpowers/*
     # treat it as a local edit and autostash it on every run (#38529).
     .hermes-bootstrap-complete
     
    +# Interrupted-update breadcrumb + recovery lock written next to the shared venv
    +# by `hermes update` / launch-time self-heal. Runtime state, never a code change
    +# — ignore so `git status` stays clean and update's autostash skips them.
    +.update-incomplete
    +.update-incomplete.lock
    +
     # Tool Search live-test harness output — non-deterministic model transcripts,
     # regenerated by scripts/tool_search_livetest.py. Never an artifact of the repo.
     scripts/out/
    ```
  - `hermes_cli/main.py`

    ```diff
    @@ -8832,6 +8832,167 @@ def _load_installable_optional_extras(group: str = "all") -> list[str]:
         return referenced
     
     
    +# Install-scoped breadcrumb dropped right before ``hermes update`` mutates the
    +# venv and cleared only after the dependency install verifies clean.  If a user
    +# kills the update mid-install (Ctrl-C, terminal close, WSL OOM), the marker
    +# survives and the next ``hermes`` launch finishes the install instead of
    +# limping along on a half-built venv (e.g. pip wiped, a core dep like Pillow
    +# never landed).  Lives next to the venv (not under $HERMES_HOME) because the
    +# venv is shared across all profiles, so a single marker covers every profile.
    +def _update_marker_path() -> Path:
    +    return PROJECT_ROOT / ".update-incomplete"
    +
    +
    +def _write_update_incomplete_marker() -> None:
    +    """Drop the interrupted-install breadcrumb. Never raises."""
    +    try:
    +        _update_marker_path().write_text(
    +            f"started={_time.time()}\npid={os.getpid()}\n", encoding="utf-8"
    +        )
    +    except OSError as exc:
    +        logger.debug("Could not write update-incomplete marker: %s", exc)
    +
    +
    +def _clear_update_incomplete_marker() -> None:
    +    """Remove the interrupted-install breadcrumb. Never raises."""
    +    try:
    +        _update_marker_path().unlink()
    +    except FileNotFoundError:
    +        pass
    +    except OSError as exc:
    +        logger.debug("Could not clear update-incomplete marker: %s", exc)
    +
    +
    +def _recover_from_interrupted_install() -> None:
    +    """Finish a dependency install that a prior ``hermes update`` left half-done.
    +
    +    Triggered on launch when ``.update-incomplete`` is present — meaning the
    +    code was pulled but the dep install was killed before it verified clean.
    +    Unconditionally bootstraps pip via ``ensurepip`` (a killed ``pip install``
    +    can wipe pip from the venv entirely, which blocks the venv from recovering
    +    on its own), then re-runs the editable ``.[all]`` install + core-dependency
    +    verification, then clears the marker.
    +
    +    Never raises: a recovery failure must not block launch.  If it can't
    +    self-heal it prints the one-line manual command and leaves the marker so
    +    the next launch tries again.
    +
    +    Concurrency: the marker lives next to the shared venv, so a gateway start
    +    plus a CLI launch (or two profiles starting at once) can both see it.  An
    +    ``O_EXCL`` lockfile ensures only one process runs the reinstall; the
    +    others skip and let the winner clear the marker.
    +
    +    Output: everything — our status lines AND the streamed pip/uv install
    +    (which inherits fd 1) — is routed to stderr.  Launches whose stdout is a
    +    protocol stream (``hermes acp`` speaks JSON-RPC on stdout) must never get
    +    install noise on stdout.
    +    """
    +    if not _update_marker_path().exists():
    +        return
    +
    +    # Skip in managed/Docker installs and on PyPI installs with no git checkout:
    +    # those don't run the source-tree update path, so a stray marker is not ours
    +    # to act on. Just clear it.
    +    if not (PROJECT_ROOT / "pyproject.toml").is_file():
    +        _clear_update_incomplete_marker()
    +        return
    +
    +    # Single-flight guard: atomically claim the recovery lock. If another
    +    # process holds it, skip — it is running the same reinstall into the same
    +    # shared venv right now. A crashed holder leaves a stale lock; break it
    +    # after an hour (well past any realistic install) so recovery can't be
    +    # wedged forever.
    +    lock_path = PROJECT_ROOT / ".update-incomplete.lock"
    +    try:
    +        fd = os.open(lock_path, os.O_CREAT | os.O_EXCL | os.O_WRONLY)
    +        os.write(fd, f"{os.getpid()}\n".encode())
    +        os.close(fd)
    +    except FileExistsError:
    +        try:
    +            if _time.time() - lock_path.stat().st_mtime > 3600:
    +                lock_path.unlink()
    +        except OSError:
    +            pass
    +        return
    +    except OSError as exc:
    +        # Couldn't create the lock (read-only fs, perms). Proceed unlocked —
    +        # the install itself will surface the real problem.
    +        logger.debug("Could not create install-recovery lock: %s", exc)
    +
    +    saved_stdout_fd = None
    +    saved_sys_stdout = sys.stdout
    +    try:
    +        # Route Python-level prints AND subprocess-inherited fd 1 to stderr
    +        # for the duration of recovery (see docstring: ACP stdout safety).
    +        try:
    +            saved_stdout_fd = os.dup(1)
    +            os.dup2(2, 1)
    +        except OSError:
    +            saved_stdout_fd = None
    +        sys.stdout = sys.stderr
    +
    +        print(
    +            "⚠ A previous `hermes update` was interrupted mid-install — "
    +            "finishing dependency installation now..."
    +        )
    +
    +        try:
    +            from hermes_cli.managed_uv import ensure_uv
    +
    +            # Always bootstrap pip first: a killed install can leave the venv with
    +            # no pip module at all, and uv may also be gone. ensurepip restores a
    +            # known-good pip so at least the plain-pip path below can proceed.
    +            try:
    +                subprocess.run(
    +                    [sys.executable, "-m", "ensurepip", "--upgrade", "--default-pip"],
    +                    cwd=PROJECT_ROOT,
    +                    capture_output=True,
    +                )
    +            except Exception as exc:
    +                logger.debug("ensurepip during install recovery failed: %s", exc)
    +
    +            uv_bin = ensure_uv()
    +            if uv_bin:
    +                uv_env = {**os.environ, "VIRTUAL_ENV": str(PROJECT_ROOT / "venv")}
    +                if _is_termux_env(uv_env):
    +                    uv_env.pop("PYTHONPATH", None)
    +                    uv_env.pop("PYTHONHOME", None)
    +                _install_python_dependencies_with_optional_fallback(
    +                    [uv_bin, "pip"],
    +                    env=uv_env,
    +                    group="termux-all" if _is_termux_env(uv_env) else "all",
    +                )
    +            else:
    +                _install_python_dependencies_with_optional_fallback(
    +                    [sys.executable, "-m", "pip"],
    +                    group="termux-all" if _is_termux_env() else "all",
    +                )
    +
    +            _clear_update_incomplete_marker()
    +            print("✓ Dependency installation recovered — your install is healthy again.")
    +        except Exception as exc:
    +            # Leave the marker in place so the next launch retries. Give the user
    +            # the exact manual recovery command in the meantime.
    +            logger.debug("Interrupted-install recovery failed: %s", exc)
    +            print("✗ Could not auto-recover the interrupted install.")
    +            print("  Recover manually with:")
    +            print(f"    cd {PROJECT_ROOT}")
    +            print(f"    {sys.executable} -m ensurepip --upgrade")
    +            print(f"    {sys.executable} -m pip install -e '.[all]'")
    +    finally:
    +        sys.stdout = saved_sys_stdout
    +        if saved_stdout_fd is not None:
    +            try:
    +                os.dup2(saved_stdout_fd, 1)
    +                os.close(saved_stdout_fd)
    +            except OSError:
    +                pass
    +        try:
    +            lock_path.unlink()
    +        except OSError:
    +            pass
    +
    +
     def _run_install_with_heartbeat(
         cmd: list[str],
         *,
    ```

    ```diff
    @@ -10759,6 +10920,13 @@ def _cmd_update_impl(args, gateway_mode: bool):
             # Reinstall Python dependencies. Prefer .[all], but if one optional extra
             # breaks on this machine, keep base deps and reinstall the remaining extras
             # individually so update does not silently strip working capabilities.
    +        #
    +        # Drop the interrupted-install breadcrumb BEFORE touching the venv. If
    +        # the install is killed mid-flight (Ctrl-C, terminal close, WSL OOM),
    +        # the marker survives and the next ``hermes`` launch finishes the
    +        # install via ``_recover_from_interrupted_install``. Cleared only after
    +        # the install + core-dependency verification completes below.
    +        _write_update_incomplete_marker()
             print("→ Updating Python dependencies...")
             from hermes_cli.managed_uv import ensure_uv, update_managed_uv
     
    ```

    ```diff
    @@ -10812,6 +10980,12 @@ def _cmd_update_impl(args, gateway_mode: bool):
                     _install_psutil_android_compat(pip_cmd)
                 _install_python_dependencies_with_optional_fallback(pip_cmd, group=install_group)
     
    +        # Core Python deps installed AND verified (the fallback helper runs
    +        # _verify_core_dependencies_installed). Clear the interrupted-install
    +        # breadcrumb now — the remaining steps (lazy refresh, node deps, web
    +        # UI, desktop rebuild) are non-core and can't brick the venv.
    +        _clear_update_incomplete_marker()
    +
             _refresh_active_lazy_features()
     
             _update_node_dependencies()
    ```

    ```diff
    @@ -13110,6 +13284,22 @@ def main():
         except Exception:
             pass
     
    +    # Self-heal a venv left half-built by an interrupted ``hermes update``
    +    # (Ctrl-C, terminal close, WSL OOM mid-install). Skip when the user is
    +    # *running* update — that flow writes and clears its own marker, and we
    +    # don't want a recovery install racing the real one. Never raises.
    +    #
    +    # The substring match is deliberately loose: argv isn't parsed yet at this
    +    # point, and the failure modes are asymmetric. Over-matching (e.g.
    +    # ``hermes skills install update``) merely defers recovery one launch;
    +    # under-matching (missing ``hermes -p work update``) would race a recovery
    +    # install against the real one. Loose wins.
    +    try:
    +        if "update" not in sys.argv[1:]:
    +            _recover_from_interrupted_install()
    +    except Exception:
    +        pass
    +
         if _try_termux_fast_tui_launch():
             return
         if _try_termux_fast_cli_launch():
    ```
  - `tests/hermes_cli/test_update_interrupted_recovery.py`

    ```diff
    @@ -0,0 +1,218 @@
    +"""Tests for interrupted-install self-heal (the ``.update-incomplete`` marker).
    +
    +Covers the breadcrumb lifecycle and the launch-time recovery guard added so a
    +``hermes update`` killed mid-install (Ctrl-C, terminal close, WSL OOM) gets
    +finished automatically on the next launch instead of leaving a half-built venv.
    +"""
    +
    +from __future__ import annotations
    +
    +from pathlib import Path
    +
    +import hermes_cli.main as m
    +
    +
    +def test_marker_round_trip(tmp_path, monkeypatch):
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    marker = m._update_marker_path()
    +    assert marker == tmp_path / ".update-incomplete"
    +    assert not marker.exists()
    +
    +    m._write_update_incomplete_marker()
    +    assert marker.exists()
    +    body = marker.read_text()
    +    assert "started=" in body
    +    assert "pid=" in body
    +
    +    m._clear_update_incomplete_marker()
    +    assert not marker.exists()
    +
    +
    +def test_clear_when_absent_is_noop(tmp_path, monkeypatch):
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    # Must not raise when the marker was never written.
    +    m._clear_update_incomplete_marker()
    +    assert not m._update_marker_path().exists()
    +
    +
    +def test_recovery_noop_without_marker(tmp_path, monkeypatch):
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    called = {"install": False}
    +    monkeypatch.setattr(
    +        m,
    +        "_install_python_dependencies_with_optional_fallback",
    +        lambda *a, **k: called.__setitem__("install", True),
    +    )
    +    m._recover_from_interrupted_install()
    +    assert called["install"] is False, "recovery must not install when no marker"
    +
    +
    +def test_recovery_clears_stray_marker_without_pyproject(tmp_path, monkeypatch):
    +    # No pyproject.toml (PyPI/Docker install) — a stray marker is not ours to
    +    # act on; recovery should just clear it without trying to install.
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    m._write_update_incomplete_marker()
    +    called = {"install": False}
    +    monkeypatch.setattr(
    +        m,
    +        "_install_python_dependencies_with_optional_fallback",
    +        lambda *a, **k: called.__setitem__("install", True),
    +    )
    +    m._recover_from_interrupted_install()
    +    assert called["install"] is False
    +    assert not m._update_marker_path().exists()
    +
    +
    +def test_recovery_runs_install_and_clears_marker(tmp_path, monkeypatch):
    +    # Source-tree install (pyproject present) with marker set → recovery should
    +    # run the dep install and clear the marker on success.
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    (tmp_path / "pyproject.toml").write_text("[project]\nname='x'\n")
    +    m._write_update_incomplete_marker()
    +
    +    seen = {"ensurepip": False, "install": False}
    +
    +    def fake_run(cmd, *a, **k):
    +        if "ensurepip" in cmd:
    +            seen["ensurepip"] = True
    +
    +        class R:
    +            returncode = 0
    +
    +        return R()
    +
    +    monkeypatch.setattr(m.subprocess, "run", fake_run)
    +    monkeypatch.setattr(m, "_is_termux_env", lambda *a, **k: False)
    +    monkeypatch.setattr("hermes_cli.managed_uv.ensure_uv", lambda: None)
    +    monkeypatch.setattr(
    +        m,
    +        "_install_python_dependencies_with_optional_fallback",
    +        lambda *a, **k: seen.__setitem__("install", True),
    +    )
    +
    +    m._recover_from_interrupted_install()
    +
    +    assert seen["ensurepip"] is True, "ensurepip must run unconditionally first"
    +    assert seen["install"] is True, "dep install must run"
    +    assert not m._update_marker_path().exists(), "marker cleared on success"
    +
    +
    +def test_recovery_keeps_marker_on_failure(tmp_path, monkeypatch):
    +    # If the install itself blows up, the marker must survive so the next
    +    # launch retries — and recovery must not raise.
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    (tmp_path / "pyproject.toml").write_text("[project]\nname='x'\n")
    +    m._write_update_incomplete_marker()
    +
    +    class R:
    +        returncode = 0
    +
    +    monkeypatch.setattr(m.subprocess, "run", lambda *a, **k: R())
    +    monkeypatch.setattr(m, "_is_termux_env", lambda *a, **k: False)
    +    monkeypatch.setattr("hermes_cli.managed_uv.ensure_uv", lambda: None)
    +
    +    def boom(*a, **k):
    +        raise RuntimeError("install died")
    +
    +    monkeypatch.setattr(
    +        m, "_install_python_dependencies_with_optional_fallback", boom
    +    )
    +
    +    # Must not raise.
    +    m._recover_from_interrupted_install()
    +    assert m._update_marker_path().exists(), "marker preserved for retry on failure"
    +
    +
    +def _stub_install_env(monkeypatch, m, seen):
    +    """Common stubs so recovery's install path is inert and observable."""
    +
    +    class R:
    +        returncode = 0
    +
    +    monkeypatch.setattr(m.subprocess, "run", lambda *a, **k: R())
    +    monkeypatch.setattr(m, "_is_termux_env", lambda *a, **k: False)
    +    monkeypatch.setattr("hermes_cli.managed_uv.ensure_uv", lambda: None)
    +    monkeypatch.setattr(
    +        m,
    +        "_install_python_dependencies_with_optional_fallback",
    +        lambda *a, **k: seen.__setitem__("install", True),
    +    )
    +
    +
    +def test_recovery_skips_when_lock_held(tmp_path, monkeypatch):
    +    # Another process is mid-recovery (fresh lockfile) — this launch must skip
    +    # the install entirely and leave both marker and lock untouched.
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    (tmp_path / "pyproject.toml").write_text("[project]\nname='x'\n")
    +    m._write_update_incomplete_marker()
    +    lock = tmp_path / ".update-incomplete.lock"
    +    lock.write_text("12345\n")
    +
    +    seen = {"install": False}
    +    _stub_install_env(monkeypatch, m, seen)
    +
    +    m._recover_from_interrupted_install()
    +
    +    assert seen["install"] is False, "must not install while another holds the lock"
    +    assert m._update_marker_path().exists(), "marker left for the lock holder"
    +    assert lock.exists(), "fresh lock must not be broken"
    +
    +
    +def test_recovery_breaks_stale_lock(tmp_path, monkeypatch):
    +    # A lock older than an hour is from a crashed holder — it gets removed so
    +    # the NEXT launch can recover (this launch still skips).
    +    import os as _os
    +
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    (tmp_path / "pyproject.toml").write_text("[project]\nname='x'\n")
    +    m._write_update_incomplete_marker()
    +    lock = tmp_path / ".update-incomplete.lock"
    +    lock.write_text("12345\n")
    +    stale = m._time.time() - 7200
    +    _os.utime(lock, (stale, stale))
    +
    +    seen = {"install": False}
    +    _stub_install_env(monkeypatch, m, seen)
    +
    +    m._recover_from_interrupted_install()
    +
    +    assert not lock.exists(), "stale lock must be broken"
    +    assert m._update_marker_path().exists()
    +
    +    # Next launch proceeds normally.
    +    m._recover_from_interrupted_install()
    +    assert seen["install"] is True
    +    assert not m._update_marker_path().exists()
    +    assert not lock.exists(), "lock released after recovery"
    +
    +
    +def test_recovery_releases_lock_after_run(tmp_path, monkeypatch):
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    (tmp_path / "pyproject.toml").write_text("[project]\nname='x'\n")
    +    m._write_update_incomplete_marker()
    +
    +    seen = {"install": False}
    +    _stub_install_env(monkeypatch, m, seen)
    +
    +    m._recover_from_interrupted_install()
    +
    +    assert seen["install"] is True
    +    assert not (tmp_path / ".update-incomplete.lock").exists()
    +
    +
    +def test_recovery_output_goes_to_stderr(tmp_path, monkeypatch, capfd):
    +    # ACP speaks JSON-RPC on stdout — recovery output (including the streamed
    +    # install, which inherits fd 1) must land on stderr only.
    +    monkeypatch.setattr(m, "PROJECT_ROOT", tmp_path)
    +    (tmp_path / "pyproject.toml").write_text("[project]\nname='x'\n")
    +    m._write_update_incomplete_marker()
    +
    +    seen = {"install": False}
    +    _stub_install_env(monkeypatch, m, seen)
    +
    +    m._recover_from_interrupted_install()
    +
    +    out, err = capfd.readouterr()
    +    assert "interrupted mid-install" not in out
    +    assert "interrupted mid-install" in err
    +    assert "recovered" in err
    ```
- **#39557: fix(cli): catch _build_web_ui exceptions to prevent half-updated state**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `db204ae2035021bb5f1e76004c13296853a139b6`, `#39780`
- **#40757: fix(cli): add update-in-progress marker to prevent stuck state after crash (PR 1/2)**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `a5c32cdf3055c1047bf08e1beb0334ad92672063`, `#42172`
- **#40758: fix(cli): spawn post-pull steps in subprocess to fix bytecode version skew (PR 2/2)**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `db204ae2035021bb5f1e76004c13296853a139b6`, `#39549`, `#39549`
- **#40995: Fix #39706: Remove incomplete rebuild_venv stub causing update crash**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `db204ae2035021bb5f1e76004c13296853a139b6`, `#39780`, `#39706`

## Fix status

- Merged to main in PR #39780 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-06-10`.
- Subsystem: `hermes_cli`