fix(skills): correct driver autoexec, handler args, active-vs-selected, bake target and migration claims

[TMHSDigital]

Closes #458
Closes #459
Closes #460
Closes #461
Closes #464

Fixes skill, rule and snippet claims that live Blender contradicts. Three existing examples gain checks, each with a catalog falsifier.

Binaries used (versions as the binaries report them): .scratch/blender-5.2.1-windows-x64/blender.exe (5.2.1 LTS, hash 9e2066aef7ef) and .scratch/blender-4.5.11-windows-x64/blender.exe (4.5.11 LTS, hash 4db51e9d1e1e). The bake-selection boundary was also probed on 5.0.1 and 5.1.2.

Per issue

#458 Drivers: autoexec and is_simple_expression

• Skill: the security section is rewritten in drivers-and-app-handlers.
  • Simple expressions always run.
  • Every driver_namespace call needs Auto Run Python Scripts, Trusted Source, or -y. This cites the manual's Drivers > Troubleshooting page.
  • Prefer driver variables and simple expressions in shared files.
  • Use driver.is_simple_expression to tell which kind you wrote. A measured table is included.
• Snippet: driver-with-custom-function.py header now carries the same caveat.
• Example: driver-wave asserts that every column's custom-function driver reports is_simple_expression == False (exit 5). Falsifier: --simple-expr writes the same profile inline as 1.4 + sin(i*0.6). The heights still match, but the run exits 5.

#459 Handler signatures

• Table: frame_change_pre and depsgraph_update_pre now read (scene, None), with a note on what to do instead. exit_pre is documented as (interactive: bool); a *args handler gets (bool, None).
• Example: driver-wave asserts the argument types of all four handlers (exit 7). This went into driver-wave rather than exit-pre-sidecar to avoid conflicting with the exit-code renumbering. Falsifier: --swap-handlers hangs each probe on the opposite list and exits 7.

#460 Active vs selected

• Skill and rule: operators and rules/type-annotate-props-and-defend-context.mdc now say:
  • active_object is None only when there is no active object: an empty scene, a deleted active object, or an override that sets it to None.
  • Active and selected are independent. Check select_get(), visible_get() and library is None.
  • Both guard examples gain a select_get() check.
• Regenerated: claude/blender-rules.md.
• Example: an assertion was added to temp-override-join, which is cheaper than a new check-only example. After select_all(DESELECT) the target stays active, select_get() is False, and selected_objects is empty (exit 13). Falsifier: --clear-active-on-deselect.

#461 Bake target must be a selected Image Texture node

• Correction to the issue's own reading: the bake uses the tree's active-texture node and, on 5.0 and later, requires that node to be selected. It is not true that only selection matters.
  • Case E: two image nodes, the selected one is not the active texture, and the bake is CANCELLED.
  • Case D/C: the only image node is selected while Principled is nodes.active, and the bake FINISHES, because that node is still the active texture.
• 4.5.11 ignores selection entirely. An active, unselected node still bakes (FINISHED).
• Skill, snippet and failure table now state this.
• Example: falsifier --unselect-target added to bake-normal-high-to-low. It exits 4 on 5.x and exits 0 on 4.5, so the catalog row carries "min_version": "5.0" and the README says so.

#464

1. bl-info-migration: new Step 4 replaces hard-coded add-on names and submodule __name__ with __package__, and cross-links custom-properties. Measured with an installed test extension on 5.2.1:
   • addons["bare_id"] raises KeyError.
   • In a submodule, __name__ is bl_ext.user_default.<id>.prefs.
   • bl_idname = __name__ registers silently, and addons[pkg].preferences is then None.
2. depsgraph / mesh-editing: both now say "one temporary mesh per evaluated object until to_mesh_clear() or re-evaluation; many objects hold one each".
   • Measured on 4.5.11 and 5.2.1: a second to_mesh() on the same object frees the previous mesh. The old Python handle then raises ReferenceError.
   • This also corrects the old "returns that same mesh" claim. The pointer matches on 5.2 but not on 4.5, and the first handle is dead on both.
3. ui-panels: the specific fallback tab name is dropped, because it could not be verified headless.

Proven by live run vs inspection

Live, headless (--background --factory-startup) on 5.2.1 and 4.5.11:

• use_scripts_auto_execute is False on factory settings.
• is_simple_expression values for 7 expressions.
• Handler argument types for the four handlers.
• active_object after deselect-all, after deleting the active object, and in an empty scene. object.delete on an active but unselected object returns CANCELLED.
• Bake cases A–H. The unselected-active case was also run on 5.0.1 and 5.1.2 (both CANCELLED).
• to_mesh lifetime.
• exit_pre passes False in background on 5.2.1.

Live, other:

• On 5.2.1, one windowed run (non-background, quit by a timer) showed exit_pre receiving True.
• The extension __package__ / addons / AddonPreferences facts come from a 5.2.1 run with an installed test extension in a temporary BLENDER_USER_RESOURCES.

Inspection only:

• Manual wording on Trusted Source / Auto Run, taken from the Drivers > Troubleshooting page.
• The claim that --background does not apply the GUI autoexec block. This comes from skills: drivers skill says driver_namespace is the security gate; custom-function drivers actually need Auto Run Python Scripts and go dead in shared files #458's evidence and the skill's existing save-and-reopen measurement; I did not re-measure it in a GUI session.
• The advice not to call evaluated_depsgraph_get() inside a depsgraph handler.
• The __package__ behaviour of deeper submodules (ui/panels.py gives ...<id>.ui). This is standard Python package semantics and was not run.

Falsifier probes (measured exits)

Example	Args	5.2.1 LTS	4.5.11 LTS
driver-wave	(none)	0	0
driver-wave	--flat-expr	3	3
driver-wave	--simple-expr	5 (16/16 drivers report is_simple_expression=True)	5
driver-wave	--swap-handlers	7 (pre got Depsgraph, post got NoneType)	7
temp-override-join	(none)	0	0
temp-override-join	--no-override	3 (unchanged)	3
temp-override-join	--clear-active-on-deselect	13 (active=None)	13
bake-normal-high-to-low	(none)	0	0
bake-normal-high-to-low	--unselect-target	4 ({'CANCELLED'}, active=True selected=False)	0 (expected; min_version 5.0, SKIP below)

python tests/run_all.py: 31 passed, 0 failed. Gallery pages were regenerated with scripts/build_gallery.py; the diff covers only the README-derived text of the three example pages, and I read it in the generated HTML. No renders changed.

🤖 Generated with Claude Code