cross-version-property-delete

Cross-version property delete

A pair of machined specimen tags that witnesses the custom ID-property delete contract from cross-version-property-delete.py and custom-properties — not the snippet's __main__, which keys off context.active_object and prints nothing in --background.

The IDs are built with bpy.data.objects.new. The Keep tag still carries ["accession"] = 42 (emissive enamel). The Clear tag had del obj["accession"] (empty pocket). Same del on 4.5 LTS and 5.x; there is no version branch.

What it witnesses: property_unset is a TypeError on a custom ID key and does not remove it. del id_block[key] does. After factory-empty, there is no active_object.

What failure each check would catch:

• exit 2 — someone set an active object; the snippet __main__ would have been the only path
• exit 3 — the ID property never landed
• exit 4 — property_unset removed the key or failed to raise
• exit 7 — del did not run (--skip-delete / --unset-instead falsify this: measured clear_has=True)

Staging

The two tags now hang from the stand's bar on steel rods. The bar used to run 0.17 m behind the plates with nothing joining them, and the "rings" were solid discs, so the plates hung on air. The bar spans both plates, the post rises to it, and the base is as wide as what it carries. Render path only: the check reads ID properties, never geometry.

Run

blender --background --python cross_version_property_delete.py --
blender --background --python cross_version_property_delete.py -- --output tags.png

--skip-delete and --unset-instead are falsification switches: both leave the Clear plate tagged and exit 7.

The --output render path measures framing against the Layer 1 band via examples/gallery_framing.py (exit 10 on violation) before writing the still.

Exit codes

Per-script sequential checks. 9 is a valid check code; there is no rule against it. 10 is the shared framing helper.

Code	Meaning
0	Success
1	Uncaught exception (FATAL wrapper)
2	argparse / usage; also an active object existed after the data-API build
3	Custom ID property did not land
4	property_unset on a custom ID key did not TypeError, or it deleted the key
5	del did not report removal
6	Keep plate lost the ID property
7	Clear plate still has the ID property (--skip-delete / --unset-instead land here)
10	Gallery framing violation
12	--output produced no file

The blender-smoke workflow runs the check on Blender 5.2 LTS and 4.5 LTS (5.1 on the weekly cron, the needs-5.1 PR label, or manual dispatch). Smoke does not pass --output, --skip-delete, or --unset-instead.