fix: preserve unreadable event config files (#3861)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/specify_cli/events.py

@@ -1983,23 +1983,25 @@ def _drop_marked_entries(entries: list) -> list:
 
 
 def _load_user_json(path: Path) -> dict | None:
-    """Load a user-owned JSON file, aborting (None) on parse failure (#22/#23).
+    """Load a user-owned JSON file, aborting (None) on read/parse failure (#22/#23).
 
     Returns the parsed dict, or ``None`` when the file is missing or cannot be
-    parsed (e.g. JSONC with comments, or temporarily malformed JSON). Callers
-    must skip the merge rather than resetting user content to ``{}``.
+    read or parsed (e.g. JSONC with comments, a temporarily malformed JSON
+    document, or an unreadable path). Callers must skip the merge rather than
+    resetting user content to ``{}``.
     """
     if not path.exists():
         return {}
     try:
         data = json.loads(path.read_text(encoding="utf-8"))
-    except (json.JSONDecodeError, ValueError) as exc:
+    except (json.JSONDecodeError, OSError, ValueError) as exc:
         logger.warning(
-            "Could not parse %s (may contain JSONC comments or be malformed); "
+            "Could not read or parse %s (it may be unreadable, contain JSONC "
+            "comments, or be malformed); "
             "skipping event-config merge to preserve user content.",
             path,
         )
-        logger.debug("Parse error detail: %s", exc)
+        logger.debug("Read/parse error detail: %s", exc)
         return None
     if not isinstance(data, dict):
         logger.warning("%s is not a JSON object; skipping event-config merge.", path)

tests/integrations/test_events.py

@@ -1411,6 +1411,19 @@ class TestTeardownDataSafety:
         # User content preserved verbatim — not reset to {}.
         assert config_path.read_text() == jsonc
 
+    def test_unreadable_config_not_overwritten_on_merge(self, tmp_path):
+        """An unreadable user config aborts the merge instead of crashing."""
+        integration = ClaudeIntegration()
+        config_path = tmp_path / ".claude/settings.json"
+        config_path.mkdir(parents=True)
+
+        install_integration_events(
+            integration, tmp_path, _claude_manifest(tmp_path),
+            {"pre_tool_use": [{"command": "speckit.tdd.validate"}]},
+        )
+
+        assert config_path.is_dir()
+
     def test_jsonc_opencode_config_not_reset(self, tmp_path):
         """#23: a malformed opencode.json is preserved, not reset to {}."""
         integration = OpencodeIntegration()