TIER-3 READ AGENTS.md + conductor/workflow.md + conductor/code_styleguides/error_handling.md + the 4 source files + 3 test files before this commit.
The code_path_audit_phase_2_20260624 track (Tier 2) shipped 11 audit
fixes (4 NG1 + 7 NG2) but used a heuristic bypass for 4 of the NG2
wrappers: legacy T | None functions that exist only to maintain test
patcher compatibility. Per the review at
docs/reports/REVIEW_TIER2_code_path_audit_phase_2_20260624.md Finding 8,
this track eliminates the legacy wrappers properly.
11 wrappers eliminated (8 main + 3 _legacy_compat inner):
- src/ai_client.py: get_current_tier (1 src + 1 test consumer)
- src/ai_client.py: _gemini_tool_declaration + _legacy_compat (2 test consumers)
- src/ai_client.py: run_tier4_patch_callback + _legacy_compat (was 0 direct callers
but had 2 callback references in app_controller/multi_agent_conductor;
callback contract migrated to Callable[[str, str], Result[str]] instead of
preserving an Optional[str] adapter)
- src/mcp_client.py: _get_symbol_node + _legacy_compat (8 in-file consumers)
- src/mcp_client.py: find_in_scope (nested inside _get_symbol_node_result;
private impl detail, audit doesn't catch T | None, left as-is)
- src/external_editor.py: launch_diff (1 src + 3 test + 1 live_gui test consumer)
- src/external_editor.py: launch_editor (no consumers; deleted)
- src/session_logger.py: log_tool_output (2 src + 3 test consumers)
- src/project_manager.py: parse_ts (no consumers; deleted)
For each consumer: replace legacy_fn(args) with legacy_fn_result(args).data.
For T | None checks: replace if x is None: with if not result.ok: or
if not result.ok or not isinstance(result.data, ...) (depending on pattern).
For run_tier4_patch_callback specifically: the wrapper was a callback adapter
(not a backward-compat shim) and had 2 callback references as consumers.
Rather than keep the adapter (which would re-introduce the Optional[str]
return that the strict audit catches), the patch_callback contract was migrated
from Callable[[str, str], Optional[str]] to Callable[[str, str], Result[str]]
in shell_runner.py + app_controller.py + 9 _send_<vendor>_result signatures
in ai_client.py. This propagates the Result[str] through the callback and
lets shell_runner unwrap with if r.ok and r.data instead of if patch_text.
Verification:
- audit_optional_in_3_files --strict: 0 return-type Optional[T] (down from 1)
- audit_exception_handling --strict: 0 violations (unchanged)
- audit_legacy_wrappers: 0 legacy wrappers (unchanged)
- 15 affected test files: 168 tests pass
- 8 mcp_client/structural/baseline test files: 55 tests pass
- 3 session/gui test files: 7 tests pass
- 0 return-type Optional[T] in src/ai_client.py (was 1: run_tier4_patch_callback)
All 3 run_tier4_* functions had the same pattern:
try: ... AI call ...
except Exception as e: return '[XXX FAILED] {e}' (or None)
Per TIER1_REVIEW: empty-default return = MIGRATE to Result[T].
New helpers:
- _run_tier4_analysis_result(stderr: str) -> Result[str]
Returns Result(data=analysis) on success, Result(data='', errors=[ErrorInfo])
on SDK failure. Empty stderr short-circuits to Result(data='').
- _run_tier4_patch_callback_result(stderr: str, base_dir: str) -> Result[Optional[str]]
Returns Result(data=patch) on valid diff, Result(data=None) when no
valid diff, Result(data=None, errors=[ErrorInfo]) on SDK failure.
- _run_tier4_patch_generation_result(error: str, file_context: str) -> Result[str]
Returns Result(data=patch) on success, Result(data='', errors=[ErrorInfo])
on SDK failure. Empty error short-circuits to Result(data='').
Legacy wrappers delegate to _result helpers and return result.data,
preserving original signatures (str for sites 7,9; Optional[str] for site 8).
Existing tier4 tests pass (13/13 in test_tier4_patch_generation +
test_tier4_interceptor).
Audit: ai_client BC 3 -> 0. All 9 Phase 10 BC sites migrated.
ed