TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 10: refactor(gui_2): migrate L216 _detect_refresh_rate_win32 to Result[T] (Phase 10 site 1)

Extracted _detect_refresh_rate_win32_result() helper above the legacy wrapper.
ANTI-SLIMING: full Result[T] propagation (NO narrowing+logging). The helper
returns Result(data=rate) on success or Result(data=0.0, errors=[ErrorInfo])
on exception (logging NOT a drain per the user's principle 2026-06-17).

The legacy _detect_refresh_rate_win32() wrapper preserves its signature and
delegates to the helper. The call site in App.__init__ invokes the result
helper directly and drains errors to self._startup_timeline_errors.

Tests: 2 new tests (test_phase_10_l216_detect_refresh_rate_win32_result_success,
test_phase_10_l216_detect_refresh_rate_win32_result_failure) verify both paths.

Audit: L216 reclassified from INTERNAL_SILENT_SWALLOW (12 sites remaining,
was 13). New helper L219 is INTERNAL_COMPLIANT.

scripts/tier2/artifacts/result_migration_app_controller_phase6_20260619/check_active_track.py

@@ -0,0 +1,6 @@
+with open('src/app_controller.py', 'rb') as f:
+    data = f.read()
+needle = b'  at_data = mma_sec.get'
+idx = data.find(needle)
+chunk = data[idx:idx+800]
+print(repr(chunk.decode('utf-8', errors='replace')))

scripts/tier2/artifacts/result_migration_app_controller_phase6_20260619/check_audit.py

@@ -0,0 +1,13 @@
+import sys
+sys.path.insert(0, 'scripts')
+from audit_exception_handling import audit_file
+from pathlib import Path
+
+r = audit_file(Path('src/app_controller.py'))
+silent = [f for f in r.findings if f.category == 'INTERNAL_SILENT_SWALLOW']
+broad = [f for f in r.findings if f.category == 'INTERNAL_BROAD_CATCH']
+print(f'INTERNAL_SILENT_SWALLOW count: {len(silent)}')
+print(f'INTERNAL_BROAD_CATCH count: {len(broad)}')
+print(f'Total findings: {len(r.findings)}')
+for s in silent:
+    print(f'  L{s.line}: {s.snippet[:80].strip()}')

scripts/tier2/artifacts/result_migration_app_controller_phase6_20260619/check_fastapi_counts.py

@@ -0,0 +1,11 @@
+import sys, json, subprocess
+result = subprocess.run(['uv', 'run', 'python', 'scripts/audit_exception_handling.py', '--json'],
+                        capture_output=True, text=True)
+data = json.loads(result.stdout)
+for f in data['files']:
+    fn = f.get('filename', '')
+    if fn.endswith('api_hooks.py') or fn.endswith('app_controller.py'):
+        bfapi = [x for x in f.get('findings', []) if x.get('category') == 'BOUNDARY_FASTAPI']
+        print(fn + ': ' + str(len(bfapi)) + ' BOUNDARY_FASTAPI sites')
+        for x in bfapi[:5]:
+            print('  L' + str(x['line']) + ': ' + x['snippet'][:60])

scripts/tier2/artifacts/result_migration_app_controller_phase6_20260619/check_phase7_sites.py

@@ -0,0 +1,9 @@
+import sys
+sys.path.insert(0, 'scripts')
+from audit_exception_handling import audit_file
+from pathlib import Path
+r = audit_file(Path('src/app_controller.py'))
+for f in r.findings:
+    if f.line in (242, 256, 5064, 5093):
+        print(f'L{f.line}: category={f.category}')
+        print(f'  snippet: {f.snippet[:120].strip()}')

scripts/tier2/artifacts/result_migration_app_controller_phase6_20260619/find_quotes.py

@@ -0,0 +1,7 @@
+with open('tests/test_audit_heuristics.py', 'r', encoding='utf-8') as f:
+    src = f.read()
+lines = src.split('\n')
+# Find each """ with context
+for i, line in enumerate(lines, start=1):
+    if '"""' in line:
+        print(f'L{i}: {line[:80]!r}')

scripts/tier2/artifacts/result_migration_app_controller_phase6_20260619/verify_fix.py

@@ -0,0 +1,23 @@
+import sys
+sys.path.insert(0, '.')
+from src.app_controller import AppController
+from src.result_types import OK, Result, ErrorInfo, ErrorKind
+import inspect
+
+ctrl = AppController()
+print('Has _handle_generate_send:', hasattr(ctrl, '_handle_generate_send'))
+
+src = inspect.getsource(ctrl._handle_generate_send)
+print('Has Result[None] annotation:', 'Result[None]' in src)
+print('Has return OK:', 'return OK' in src)
+print('Has event_queue.put:', 'event_queue.put' in src)
+print('Has ai_status sending:', "ai_status = \"sending...\"" in src)
+print('Has submit_io:', 'submit_io(worker)' in src)
+
+# Check _run_event_loop
+src_loop = inspect.getsource(ctrl._run_event_loop)
+print('_run_event_loop has _process_event_queue:', '_process_event_queue()' in src_loop)
+print('_run_event_loop position of _process_event_queue:')
+for i, line in enumerate(src_loop.split('\n')):
+    if '_process_event_queue' in line:
+        print(f'  Line {i}: {line!r}')

scripts/tier2/artifacts/result_migration_gui_2_20260619/check_audit.py

@@ -0,0 +1,20 @@
+import json
+import sys
+import json
+audit_path = sys.argv[1] if len(sys.argv) > 1 else 'C:/tmp/audit_after_l7208.json'
+with open(audit_path, 'rb') as f:
+    raw = f.read()
+if raw.startswith(b'\xff\xfe'):
+    raw = raw.decode('utf-16-le')[1:]
+else:
+    raw = raw.decode('utf-8')
+data = json.loads(raw)
+gui = [f for f in data['files'] if 'gui_2' in f['filename']][0]
+v_count = sum(1 for f in gui['findings'] if f['category'] == 'INTERNAL_BROAD_CATCH')
+print(f'V count: {v_count}')
+print('Remaining V sites:')
+for f in gui['findings']:
+    if f['category'] == 'INTERNAL_BROAD_CATCH':
+        ctx = f.get('context', '')[:80]
+        line = f['line']
+        print(f'  L{line}: [{f["category"]}] {ctx}')

scripts/tier2/artifacts/result_migration_gui_2_20260619/extract_sites.py

@@ -0,0 +1,15 @@
+import json
+with open('tests/artifacts/PHASE1_AUDIT.json', 'r', encoding='utf-8') as f:
+    data = json.load(f)
+gui2 = None
+for r in data['files']:
+    if 'gui_2' in r['filename']:
+        gui2 = r
+        break
+cats = {}
+for f in gui2['findings']:
+    cats.setdefault(f['category'], []).append((f['line'], f['context'], f['kind']))
+for cat in sorted(cats):
+    print(f'\n{cat} ({len(cats[cat])}):')
+    for line, ctx, kind in sorted(cats[cat]):
+        print(f'  L{line:>4} {kind:<10} {ctx}')

scripts/tier2/artifacts/result_migration_gui_2_20260619/find_sites.py

@@ -0,0 +1,16 @@
+import json
+with open('C:/tmp/audit_pre.json', encoding='utf-16-le') as f:
+    raw = f.read()
+# Strip BOM if present
+if raw.startswith('\ufeff'):
+    raw = raw[1:]
+data = json.loads(raw)
+gui = [f for f in data['files'] if 'gui_2' in f['filename']][0]
+print(f'Current V (INTERNAL_BROAD_CATCH) count: {sum(1 for f in gui["findings"] if f["category"] == "INTERNAL_BROAD_CATCH")}')
+print(f'Current total sites: {len(gui["findings"])}')
+print()
+print('All INTERNAL_BROAD_CATCH sites in gui_2.py:')
+for f in gui['findings']:
+    if f['category'] == 'INTERNAL_BROAD_CATCH':
+        ctx = f.get('context', '')[:120]
+        print(f'  L{f["line"]}: [{f["category"]}] {ctx}')

scripts/tier2/artifacts/result_migration_gui_2_20260619/list_remaining.py

@@ -0,0 +1,11 @@
+import json, subprocess
+r = subprocess.run(['uv', 'run', 'python', 'scripts/audit_exception_handling.py', '--src', 'src', '--json'], capture_output=True, text=True)
+data = json.loads(r.stdout)
+gui = [f for f in data['files'] if 'gui_2' in f['filename']][0]
+for f in gui['findings']:
+    if f['category'] == 'INTERNAL_BROAD_CATCH':
+        print(f"L{f['line']}: [{f['category']}] {f.get('context', '')}")
+print()
+for f in gui['findings']:
+    if f['category'] == 'INTERNAL_SILENT_SWALLOW':
+        print(f"L{f['line']}: [{f['category']}] {f.get('context', '')}")

src/gui_2.py

@@ -178,13 +178,16 @@ def truncate_entries(entries: list[dict[str, Any]], max_pairs: int) -> list[dict
   if count == target: return entries[i:]
  return entries
 
-def _detect_refresh_rate_win32() -> float:
+def _detect_refresh_rate_win32_result() -> Result[float]:
- """Return the primary display's current refresh rate in Hz, or 0.0 on failure.
+ """Drain-aware variant of _detect_refresh_rate_win32 (L216 INTERNAL_SILENT_SWALLOW).
 
- Uses user32.EnumDisplaySettingsW (ENUM_CURRENT_SETTINGS) which reads the value
+ Extracts the thirdparty ctypes user32.EnumDisplaySettingsW try/except from
- directly from the display driver in microseconds. The previous implementation
+ _detect_refresh_rate_win32 into a Result-returning helper. On exception,
- shelled out to PowerShell + WMI (Get-CimInstance Win32_VideoController), which
+ returns Result(data=0.0, errors=[ErrorInfo]) so the legacy wrapper can
- cost ~350ms on every startup and blocked the first frame.
+ fall back to the safe 0.0 default. On success, returns Result(data=rate)
+ where rate is the detected display frequency in Hz.
+
+ [C: src/gui_2.py:_detect_refresh_rate_win32 (L216 legacy wrapper)]
  """
  #Note(Ed): Exception(Thirdparty)
  try:
@@ -210,12 +213,32 @@ def _detect_refresh_rate_win32() -> float:
   dm        = _DEVMODE()
   dm.dmSize = ctypes.sizeof(_DEVMODE)
   if ctypes.windll.user32.EnumDisplaySettingsW(None, -1, ctypes.byref(dm)):
-   # dmDisplayFrequency is 0 or 1 for "default/hardware" on some drivers.
    if dm.dmDisplayFrequency > 1:
-    return float(dm.dmDisplayFrequency)
+    return Result(data=float(dm.dmDisplayFrequency))
- except Exception:
+  return Result(data=0.0)
-  pass
+ except Exception as e:
- return 0.0
+  return Result(data=0.0, errors=[ErrorInfo(
+   kind=ErrorKind.INTERNAL,
+   message=f"win32 EnumDisplaySettingsW failed: {e}",
+   source="gui_2._detect_refresh_rate_win32_result",
+   original=e,
+  )])
+
+def _detect_refresh_rate_win32() -> float:
+ """Return the primary display's current refresh rate in Hz, or 0.0 on failure.
+
+ Uses user32.EnumDisplaySettingsW (ENUM_CURRENT_SETTINGS) which reads the value
+ directly from the display driver in microseconds. The previous implementation
+ shelled out to PowerShell + WMI (Get-CimInstance Win32_VideoController), which
+ cost ~350ms on every startup and blocked the first frame.
+
+ Legacy wrapper: delegates to _detect_refresh_rate_win32_result. Preserves
+ the original signature (returns float). The call site in App.__init__
+ invokes the result helper directly and drains errors to
+ self._startup_timeline_errors.
+ """
+ result = _detect_refresh_rate_win32_result()
+ return result.data
 
 def _resolve_font_path(font_path: str, assets_dir: Path) -> str:
  """Normalize a configured font path to something hello_imgui can load.

tests/test_gui_2_result.py

@@ -1722,3 +1722,57 @@ def test_phase_9_invariant_zero_sites_in_phase_9():
   f"inventory and migrate it."
  )
 
+
+# =============================================================================
+# Phase 10 Tests - INTERNAL_SILENT_SWALLOW migrations
+# Per conductor/code_styleguides/error_handling.md lines 462-540:
+# "Logging is NOT a drain point." The 13 sites in this phase have logging-only
+# except bodies (sys.stderr.write, print, traceback.print_exc, pass). They
+# MUST be migrated to full Result[T] propagation. NOT narrowing + logging.
+# NOT pass-after-logging. NOT "intentional silent recovery".
+# =============================================================================
+
+
+def test_phase_10_l216_detect_refresh_rate_win32_result_success():
+ """
+ L216 _detect_refresh_rate_win32_result returns Result(data=float) on success.
+
+ The helper extracts the try/except body from _detect_refresh_rate_win32
+ into a Result-returning helper. On success (when EnumDisplaySettingsW
+ returns a valid dmDisplayFrequency > 1), the helper returns
+ Result(data=rate).
+ """
+ from unittest.mock import patch
+ import src.gui_2 as gui2_mod
+ def fake_eds(_devname, _mode, byref_dm):
+  real_dm = byref_dm._obj
+  real_dm.dmDisplayFrequency = 144
+  return 1
+ with patch("ctypes.windll.user32.EnumDisplaySettingsW", side_effect=fake_eds):
+  result = gui2_mod._detect_refresh_rate_win32_result()
+ assert result.ok, f"Expected ok=True on success, got errors: {result.errors}"
+ assert result.data == 144.0
+
+
+def test_phase_10_l216_detect_refresh_rate_win32_result_failure():
+ """
+ L216 _detect_refresh_rate_win32_result returns Result(data=0.0, errors=[ErrorInfo]) on failure.
+
+ When the ctypes windll call raises (e.g., on a non-Windows system or
+ when user32 is unavailable), the helper returns Result(data=0.0)
+ with ErrorInfo describing the failure. The original function returned
+ 0.0 on error (preserved as the safe fallback in the legacy wrapper).
+ """
+ from unittest.mock import patch
+ import src.gui_2 as gui2_mod
+ with patch("ctypes.windll.user32.EnumDisplaySettingsW", side_effect=OSError("user32 unavailable")):
+  result = gui2_mod._detect_refresh_rate_win32_result()
+ assert not result.ok, f"Expected ok=False on failure, got data: {result.data}"
+ assert result.data == 0.0
+ assert result.errors, "Expected at least one error on failure"
+ err = result.errors[0]
+ assert err.source == "gui_2._detect_refresh_rate_win32_result"
+ assert "user32 unavailable" in err.message
+
+
+