From 19f5641706796d3731053a04e1605afc0c08e84d Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 3 Sep 2026 19:55:15 +0200
Subject: [PATCH] Address review: decorator anchored guard, validated stamp
 path, max mtime age probe, stray file reclaim

---
 script/helpers.py             |  3 ++-
 tests/integration/conftest.py | 32 +++++++++++++++++++++++---------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/script/helpers.py b/script/helpers.py
index 199660b6a8..2fcfe3e1f9 100644
--- a/script/helpers.py
+++ b/script/helpers.py
@@ -1105,6 +1105,7 @@ def get_components_per_integration_fixture() -> dict[str, set[str]]:
 
 _TEST_FUNC_RE = re.compile(r"async def (test_\w+)")
 _SHARED_YAML_RE = re.compile(r"@pytest\.mark\.shared_yaml\([\"'](\w+)[\"']\)")
+_SHARED_YAML_DECORATOR_RE = re.compile(r"@pytest\.mark\.shared_yaml\(")
 
 
 @cache
@@ -1126,7 +1127,7 @@ def get_fixture_to_test_files() -> dict[str, frozenset[str]]:
             result.setdefault(base_name, set()).add(rel_path)
         # Shared fixtures are named by marker, not by a test function
         names = _SHARED_YAML_RE.findall(content)
-        if len(names) != content.count("pytest.mark.shared_yaml("):
+        if len(names) != len(_SHARED_YAML_DECORATOR_RE.findall(content)):
             # A wrapped or non-literal marker would silently drop the mapping
             # and CI would select no tests for that fixture
             raise ValueError(
diff --git a/tests/integration/conftest.py b/tests/integration/conftest.py
index 2318dab39f..fc84637317 100644
--- a/tests/integration/conftest.py
+++ b/tests/integration/conftest.py
@@ -329,28 +329,39 @@ def _shared_build_dir(name: str) -> Path:
     return SHARED_BUILDS_ROOT / (_shared_build_prefix(name) + key)
 
 
-def _read_stamp(stamp: Path) -> Path | None:
+def _read_stamp(stamp: Path, shared_dir: Path) -> Path | None:
     """ELF path recorded by the last completed compile, or None."""
     try:
         text = stamp.read_text(encoding="utf-8").strip()
-    except OSError:
+    except FileNotFoundError:
         return None
-    return Path(text) if text else None
+    except OSError as err:
+        warnings.warn(f"Cannot read {stamp}: {err}", stacklevel=2)
+        return None
+    if not text:
+        return None
+    built = Path(text)
+    # Never trust a stamp pointing outside its own build dir as an unlink target
+    return built if shared_dir in built.parents else None
 
 
 def _unused_since(stale: Path, cutoff: float) -> bool:
     """Whether a build dir looks untouched since cutoff; unknown counts as used."""
-    # .built is rewritten by every completed compile; a dir without one never
-    # finished a build, and its own mtime covers a racing mkdir
+    # Newest of the .built stamp (rewritten by every completed compile) and the
+    # dir itself (freshened by a worker claiming the dir before locking)
+    newest: float | None = None
     for probe in (stale / ".built", stale):
         try:
-            return probe.stat().st_mtime < cutoff
+            mtime = probe.stat().st_mtime
         except FileNotFoundError:
             continue
+        except NotADirectoryError:
+            return True  # a stray file where a dir should be; reclaimable
         except OSError as err:
             warnings.warn(f"Cannot age-probe {stale}: {err}", stacklevel=2)
             return False
-    return False
+        newest = mtime if newest is None else max(newest, mtime)
+    return newest is not None and newest < cutoff
 
 
 def _prune_stale_builds(name: str, keep: Path) -> None:
@@ -367,8 +378,11 @@ def _prune_stale_builds(name: str, keep: Path) -> None:
             continue
         try:
             lock_file = (stale / ".lock").open("w")
-        except (FileNotFoundError, NotADirectoryError):
+        except FileNotFoundError:
             continue  # pruned by another worker meanwhile
+        except NotADirectoryError:
+            stale.unlink(missing_ok=True)  # a stray file, not a build dir
+            continue
         except OSError as err:
             warnings.warn(f"Cannot prune {stale}: {err}", stacklevel=2)
             continue
@@ -512,7 +526,7 @@ async def compile_esphome(
             # later workers skip the config re-read in _resolve_compiled_binary
             stamp = shared_dir / ".built"
             if (built := _shared_elf_paths.get(shared_dir)) is None:
-                built = await loop.run_in_executor(None, _read_stamp, stamp)
+                built = await loop.run_in_executor(None, _read_stamp, stamp, shared_dir)
             # Delete the ELF before compiling: whatever exists afterwards is
             # this compile's output, so no staleness check is ever needed
             if built is not None: