Lower Lua class instances to recycled integer IDs

[Frotty]

Summary

• represent every regular Lua class instance as a positive integer ID
• store instance fields in canonical per-field Lua tables indexed by object ID
• recycle IDs on destroy and clear inherited, reference, and array field slots before reuse
• dispatch virtual calls through the live class descriptor while keeping direct calls direct
• preserve class-to-index, index-to-class, instanceof, typeId, ondestroy, generics, and field-iteration behavior

This is the independent follow-up to #1261 and closes #1262.

Semantics

Wurst already has explicit destroy and ondestroy lifetime semantics. The new representation follows the Jass object model:

• allocation reuses a free ID or increments the maximum ID
• destroy runs existing ondestroy lowering, clears all instance storage, removes the live descriptor, then recycles the ID
• instanceof is false for destroyed IDs
• virtual dispatch and typeId reject dead IDs through the absent descriptor
• after ID reuse, stale references alias the new object, matching Jass
• closures capture the same integer ID and retain it until their explicit lifetime ends
• array-valued fields still own Lua array tables because those values are mutable reference-like storage

Static class descriptors remain Lua tables. This removes per-instance tables and metatables only.

Directional Lua 5.3 microbenchmarks

One million allocate/write/destroy iterations:

Representation	Time
instance tables	0.156 s
integer IDs plus explicit cleanup	0.078 s

Two hundred thousand retained objects, twenty field-access rounds:

Representation	Time
instance tables	0.278 s
integer IDs plus static fields	0.068 s

Peak memory for two hundred thousand retained objects with two fields:

Representation	Peak
instance tables	40,034 KiB
IDs, class map, and static fields	16,384 KiB

These are directional bundled-Lua 5.3 microbenchmarks, not Warcraft III frame benchmarks.

Verification

Focused tests passed:

• LuaBackendAuditTests
• LuaTranslationTests
• FieldIterationTests
• ClosureTests
• LuaTypecastingTests
• GenericsTests
• GenericsWithTypeclassesTests
• targeted lifecycle, generic-field, and field-iteration reruns after canonical-field deduplication

Coverage includes inheritance, polymorphic dispatch, instanceof, typeId, ondestroy, reference cleanup, fixed arrays, ID reuse, dead/stale references, class-index casts, generic canonical fields, and generated-output shape.

The full suite was intentionally not rerun locally; CI is authoritative.

[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-29T09:01:46.165778Z	71a934d	Manual request

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[Frotty]

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Codex Review: Didn't find any major issues. Another round soon, please!

Reviewed commit: 71a934d2f4

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