Phase 11.3.5. The original try/except (OSError, ValueError): mtime = 0.0
in get_cached_tree is now extracted to a Result-returning helper.
The helper returns Result[float]; the caller uses .data (0.0 fallback) and
can inspect .errors. The convention requires Result[T] for try/except sites
that can fail; the helper satisfies this requirement.
Audit post-migration:
- _get_mtime_safe L48 = INTERNAL_COMPLIANT (Heuristic A) ✓
- get_cached_tree L92 = no try/except for mtime (extracted)
Tests: 24/24 pass (test_ast_parser, test_file_cache_no_top_level_tree_sitter).
Migrates 5 SILENT_SWALLOW sites to full Result[T] pattern:
session_logger.py (4 sites):
1. log_api_hook - returns Result[bool] (was None)
2. log_comms - returns Result[bool] (was None)
3. log_tool_call - returns Result[Optional[str]] (was Optional[str])
4. log_cli_call - returns Result[bool] (was None)
file_cache.py (1 site):
- L98: removed dead code (try/except StopIteration around
next(iter(_ast_cache)) is unreachable because we just checked
len(_ast_cache) >= 10)
Updates tests/test_session_logger_optimization.py to extract
result.data from the new Result-based API.
All callers of these log_* functions previously ignored the
return value; they continue to ignore the new Result return
value (backwards-compatible).
Sub-track 2B: 4 violations cleared. Added 'from __future__ import annotations' + TYPE_CHECKING import for tree_sitter/tree_sitter_python/tree_sitter_cpp/tree_sitter_c. Runtime access via _require_warmed() in ASTParser.__init__. 6 new tests in tests/test_file_cache_no_top_level_tree_sitter.py. All 25 tests pass (6 new + 19 existing).