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)

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.