john/McRogueFace
1
0
Fork 0
Code Issues 43 Pull requests Projects Releases Wiki Activity

fix(bindings): route every drawable wrapper through PythonObjectCache

Browse source 
`.parent` allocated a brand-new Python wrapper on every read, so object
identity never held: `kid.parent is parent` was False, and so was
`kid.parent is kid.parent`. A Frame/Grid subclass reached through .parent
came back as the base type with its Python attributes gone, and `.parent`
could not be used as a dict key or set member.

The cache-aware converter already existed -- convertDrawableToPython in
UICollection.cpp -- but was file-local, so three other paths hand-rolled
their own tp_alloc switch and skipped the cache:

  - UIDrawable::get_parent      (the filed bug)
  - find_in_collection          (mcrfpy.find / find_all)
  - UIEntityCollection concat and slice __getitem__

The entity sites were the worst of them: a duplicate wrapper's tp_dealloc
unconditionally clears UIEntity::pyobject, destroying the #266 subclass
identity ref held by the *original* wrapper.

Promote the converter to UIDrawable::pyobject_for and route all sites
through it; add the matching convertEntityToPython for entities. This also
gives .parent the Line/Circle/Arc/Viewport3D arms it never had (they
previously fell through to None).

Residual gap, deliberately not closed here: the cache holds weakrefs, so a
subclass wrapper GC'd while only C++ holds the object still resurrects as
the base type. Closing that needs an owner-held strong ref (the #348
pattern) and is a lifetime design decision; filed separately.

Verified A/B: 17 of the new test's 22 checks fail pre-fix, all pass after.
Suite 330/330. Also corrects CLAUDE.md, which documented the long-deleted
RET_PY_INSTANCE macro and recommended bare tp_alloc as the "most common"
pattern -- i.e. taught this exact bug.

closes #369
This commit is contained in:
John McCardle 2026-07-13 23:37:01 -04:00
commit ce15469ffc
9 changed files with 346 additions and 324 deletions
Download patch file Download diff file Expand all files Collapse all files

2
api/manifest.json
View file

File diff suppressed because one or more lines are too long