Disable version history instead of crashing on an unusable .git

A config dir bind-mounted from a git submodule has a .git pointer file
whose target lives in the parent repo's .git/modules tree; inside the
container that tree isn't mounted, so git init over the pointer aborts.
The GitCommandError (a CalledProcessError, not OSError) escaped
discover_or_init's catch and crash-looped startup.

Detect an unusable .git before init and disable cleanly, and broaden the
catch to any git setup failure so version history stays the soft,
optional feature it's documented to be.

Author: bdraco

esphome_device_builder/controllers/version_history/git_repo.py

@@ -191,8 +191,19 @@ def discover_or_init(self) -> None:
                     self.config_dir,
                     toplevel,
                 )
+            elif (self.config_dir / ".git").exists():
+                # rev-parse found no work tree yet ``.git`` is present: an
+                # unusable git dir (a submodule / worktree pointer whose
+                # target isn't mounted, or a corrupt repo). Re-initialising
+                # over it fails, so disable rather than crash on init.
+                _LOGGER.info(
+                    "Config dir %s has a .git git can't use here (likely a submodule or "
+                    "worktree whose git dir isn't mounted); version history disabled",
+                    self.config_dir,
+                )
+                return
             self._init_repo()
-        except OSError as exc:
+        except (OSError, subprocess.CalledProcessError) as exc:
             _LOGGER.warning("Could not set up version-history git repo: %s", exc)
 
     def _discover_toplevel(self) -> Path | None:

tests/controllers/version_history/test_git_repo.py

@@ -74,6 +74,39 @@ def test_init_creates_repo_and_gitignore(tmp_path: Path) -> None:
     assert "Initialize version history" in _git(tmp_path, "log", "--format=%s")
 
 
+def test_unusable_git_pointer_disables_without_raising(tmp_path: Path) -> None:
+    """A ``.git`` pointing at a missing git dir (broken submodule) disables, not crash."""
+    # Mirrors a submodule whose parent ``.git/modules`` tree isn't mounted:
+    # ``git init`` over this pointer aborts with ``fatal: not a git repository``.
+    (tmp_path / ".git").write_text("gitdir: ./nonexistent/git/dir\n", encoding="utf-8")
+    repo = GitRepo(config_dir=tmp_path)
+
+    repo.discover_or_init()
+
+    assert not repo.enabled
+
+
+def test_init_failure_disables_without_raising(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """A ``git init`` that exits non-zero disables the feature instead of crashing."""
+    real_run = subprocess.run
+
+    def _fake(cmd: list[str], **kwargs: object) -> subprocess.CompletedProcess[str]:
+        if "init" in cmd:
+            return subprocess.CompletedProcess(cmd, 128, "", "fatal: boom")
+        return real_run(cmd, **kwargs)  # type: ignore[arg-type]
+
+    monkeypatch.setattr(
+        "esphome_device_builder.controllers.version_history.git_repo.subprocess.run", _fake
+    )
+    repo = GitRepo(config_dir=tmp_path)
+
+    repo.discover_or_init()
+
+    assert not repo.enabled
+
+
 def test_adopts_existing_repo_without_touching_gitignore(tmp_path: Path) -> None:
     """A pre-existing work tree is adopted; the user's .gitignore is untouched."""
     _make_repo(tmp_path)