Codacy backlog: 443 issues, mostly Prospector/Pyflakes findings

Bắt đầu với ruff check --select F src/machinevisiontoolbox tests và kiểm tra 29 vị trí F821 được liệt kê, phân biệt các vấn đề thực sự khi chạy với mã chết hoặc không thể truy cập và các vấn đề trong test. Trước tiên hãy phân loại hoặc sửa các phát hiện đó, sau đó chạy các test liên quan; hoàn thành giai đoạn này có nghĩa là mọi phát hiện F821 đều đã được xử lý, trong khi các danh mục lint rộng hơn vẫn là công việc tiếp theo riêng biệt.

Raised 2026-07-29 when the user pointed at the repo's Codacy dashboard
(443 issues total) and asked how much overlaps with the mixin/hygiene
work happening the same day. Verified: only the bare-except finding
(see git history, since fixed) genuinely overlapped. Everything else is
a distinct, much larger body of work, deliberately not tackled in that
pass — logging the real numbers here instead of re-deriving them from
scratch next time.

Codacy's Python analysis engine is Prospector (bundles Pylint +
Pyflakes + Bandit + pycodestyle + pydocstyle + mccabe) — confirmed via
the dashboard's own "Prospector's documentation" tab, and pattern names
like Avoid Dangerous Mutable Default Arguments / Audit Dangerous Subprocess Usage that are textbook Pylint/Bandit rule names. Codacy's
298-count "Detect Python Source Code..." bucket is all Pyflakes
findings grouped under one umbrella pattern, not broken out by code the
way ruff/raw pyflakes do.

Reproduced locally with ruff check --select F src/machinevisiontoolbox tests against clean origin/main, 2026-07-30: 883 hits (not
directly comparable to Codacy's 298 — different default
exclusions/config, and this sweep includes tests/, which Codacy's
dashboard count may not). By code:

F405/F403 (star-import ambiguity) dominate the count but are mostly
a style/tooling-friction issue, not bugs — this codebase leans on
from machinevisiontoolbox.base import *-style re-exports
deliberately (see the mypy wildcard-re-export issue for the
concrete downside of that pattern). F401/F841/F811 are typical
accumulated-cruft categories, individually low-risk to clean up but
numerous.

F821 (undefined name) is different — this is a real-bug class, not
style: a name that doesn't exist would raise NameError at runtime
if that code path is ever actually executed. All 29 instances, by
location:

• BundleAdjust.py:382,590,592 — undefined c, retain, g2
• ImageSpatial.py:116,121,328,330-332,340-342,1106 — undefined
  _border_opt, border_value, value, a, kv (kv appears 4
  times), conn
• VisualServo.py:186,412,444,1351-1353,1403 — undefined Animate,
  plot, history, camera, SphericalCamera, kwargs, pt
• blocks/camera.py:287,288 — undefined state (x2)
• tests/test_camera.py:191,192,194,195,198,200 — undefined x, y
  (likely a real bug in the test, not production code — check
  whether these lines actually run or are dead/unreachable test code)

Codacy's Pylint/Bandit-derived counts (the non-Pyflakes ~145 of the
443) weren't independently reproduced locally — the dashboard is the
source of truth for those categories (mutable default arguments,
assert usage, subprocess/exec/urlopen auditing, etc.).

Fix

Not a single pass. Suggested order: (1) triage the 29 F821 hits first
— for each, determine real bug vs. genuinely dead/unreachable code, fix
or delete accordingly; (2) F401/F811 next, mechanical and
ruff --fix-automatable for most cases; (3) F841 case-by-case (some
may be intentional, e.g. unpacking for side effects); (4) F405/F403
last and only if the codebase-wide star-import convention itself is
ever reconsidered — otherwise these will just regenerate.

Two more concrete instances, PRs #32/#33, 2026-07-30: Codacy
flagged type shadowing the builtin at ImageWholeFeatures.py:1213
(Histogram.plot's signature, PR #32) and again at :1570
(_compute_plot_series, the extraction in PR #33 that copied plot's
type parameter into a new method). Deliberately not renamed in
either PR — type= is public API (hist.plot(type="pdf")), a rename
needs a proper deprecation cycle. If picked up: this method
already has a precedent for exactly this — bar= is kept as a
deprecated alias for filled= with a DeprecationWarning
(ImageWholeFeatures.py, same method) — mirror that pattern: add
kind= as the real parameter, deprecate type= as an alias. Do this
as its own PR after #32 and #33 are both merged, not before —
branching the rename off pre-#32 main would conflict with both of
those on the same lines.

PR #33 also surfaced 3 more Codacy findings while extracting
Image.__getitem__'s nested closures (ImageCore.py): max as a
parameter name (:2792, _lenkey — carried over verbatim from the
original nested lenkey(key, max), not introduced by the extraction)
and two F405 star-import-ambiguity hits (:352 Dtype, :2812
Any, both from machinevisiontoolbox.mvtb_types's star-import) —
already covered by the F405 finding above, not a new pattern.