# RC-049: Review of PY-FIX-001

## Metadata
| Key | Value |
| --- | --- |
| ID | RC-049 |
| CrossReference | [PY-FIX-001], [QC-PY-001] |

## Version History
| Date | Status | Author | Reviewer | Change | Commit |
| --- | --- | --- | --- | --- | --- |
| 2026-10-15 | Accepted | Jens Tirsvad Nielsen | AI as stand-in for S01 | Initial version | [061b4f4] |

---

## Artifact Under Review

- Instance reviewed: [PY-FIX-001]
- Checklist used: [QC-PY-001]
- Scope: full review
- Language and domain: n/a (technical type)
- Language reviewer: none
- Mode: autonomous, not independent (reviewer is `AI as stand-in for S01`)

## Checklist Results

| # | Criterion | Status | Evidence/Notes |
| --- | --- | --- | --- |
| 1 | Packages, modules, functions, variables, classes and constants follow PEP 8 casing (`snake_case`, `PascalCase`, `UPPER_SNAKE`) | Pass | The fixture and names follow PEP 8 (`fake_tk_root`). |
| 2 | Names state purpose in the domain's language; no unexplained abbreviations, no single-letter names outside tiny scopes | Pass | Names state purpose. |
| 3 | Code is produced by the project's formatter and passes its linter with no unexplained suppressions | Pass | `ruff check` and `ruff format --check` pass with no suppressions. |
| 4 | Every function and method signature is type-annotated, including `-> None` | Pass | The fixture is annotated `-> None`; `mypy --strict` passes on 45 source files. |
| 5 | No bare `except:`, no swallowed exceptions; specific exceptions are raised and the cause is kept (`raise ... from`) | Pass | No exception handling in the change. |
| 6 | No mutable default arguments and no shadowed builtins | Pass | No mutable defaults. |
| 7 | Files, locks and connections are managed with context managers | N-A | No file handling in the change. |
| 8 | Public modules, classes and functions have docstrings that say what, not how | N-A | Tests are excluded from the docstring rules; the fixture has a one-line docstring. |
| 9 | Logging uses `logging`, not `print`; no secrets or personal data in log output | Pass | No `print`, no logging in the change. |
| 10 | Classes and operations trace to the Design Class Diagram they implement; deviations are recorded | Pass | No class or operation changed; the change is in a test of `app.main`. |
| 11 | Tests exist for new behaviour, are named for the behaviour, and do not depend on order or the network | Pass | The change makes the test independent of a real Tk root: 20 consecutive full runs (216 tests) were green after 2 failures in 12 runs before; real Tk stays covered by `tests/e2e`. |
| 12 | Type checker runs in strict mode without errors; `Any` is justified in a comment | Pass | `mypy --strict` reports no issue. |
| 13 | Dependencies are declared and pinned in the project's dependency file, none unused | Pass | No dependency change. |
| 14 | Each piece of knowledge (a business rule, constant, format, validation or query) is defined in one place; code is merged only where it expresses the same knowledge, not where it merely looks alike | Pass | The fake root is the module's existing `_FakeRoot`, used once by an autouse fixture instead of per test. |
| 15 | Imports point inward: business-rule modules import no framework, database, UI or delivery-mechanism code, and there are no import cycles | Pass | No source import changed; `lint-imports` kept. |
| 16 | SOLID holds: a class or module has one reason to change; new behaviour is added by extension, not by editing a type test in several places; subclasses honour the contract of their base; protocols are narrow; high-level code depends on protocols or abstract types and receives its implementations | Pass | One fixture with one responsibility. |
| 17 | Source is laid out in the layers and folders of the clean architecture folder structure (`domain`, `application`, `infrastructure`, `presentation` packages under `src/`, and `unit`, `integration` and `e2e` under `tests/`), in `snake_case`, and imports between the layers point inward | Pass | Test file stays in `tests/unit`. |
| 18 | File and folder names are English, contain no space and no character outside letters, digits, `-`, `_` and `.`, and follow the casing of the language for files | Pass | File names unchanged. |

## Overall Verdict

Go — every Mandatory criterion passes. Reviewed by AI as stand-in for S01; not independent of the author.

Defect fixed: an unpatched `app.main` call created a real `tk.Tk()` inside a unit test, which failed in about 1 of 6 full runs (the only Tk process limit and Tcl handle problem seen in MIL-005). Found after the MIL-009 merge, outside any milestone task, so no issue is closed. Go.

## Action Items

| Action | Owner | Due |
| --- | --- | --- |
| none | - | - |

---

[PY-FIX-001]: ../../../tests/unit/test_app.py
[QC-PY-001]: ../../../framework/qc/code/qc-programming-python.md
[061b4f4]: https://git.tirsystem.com/Tirsvad-Udemy-100-days-of-code/031-flash-card/commit/061b4f48b5d49e6800656c95d79df707e07ec0f3