[makspll]

Stacked on #651. Last of the script system PRs.

Inline values (generic, second commit)

• ScriptValue::Value(InlineValue): V<T> returns any T of at most 16 bytes with no drop glue (e.g. Entity, Vec3, Quat) stored inline instead of in an allocated reference.
  • Decided at compile time (const fn is_inline::<T>() inside the monomorphized IntoScript for V<T>), so no registry lookups.
  • The value carries a per-type static vtable: type id, as_reflect, into_reference.
• Scripts can't tell values from references. One generic wrapper per language (LuaValue / RuneValue) holds the inline value:
  • Non-mutating methods (dispatch::index_value), operators and printing use it directly.
  • Anything that needs a place (fields, assignments, M<T> methods, iteration) first promotes it in place to an allocated reference, i.e. what every V<T> result was before. Variables sharing the value see the change.
  • Field and element reads always return references into the place.
• Conversions: R<T> holds a copy of an inline value, exact type only like for references (a structural from_reflect made a union pick Vec3 for a Quat). Its field is private now. V<T> converts like from a reference. M<T> only accepts values as a promoted receiver.

Plain list query results (first commit)

• Query results are lists {entity, a, b} (result[1], result[2] in Lua, result[0], result[1] in Rune), from script systems and from world.query():build().
• The entity() / components() script functions are removed.

Numbers (medians of 3 interleaved rounds against #651, ns)

bench	before	after
operator	846	632 (−25%)
method call returning value	995	841 (−15%)
method call	644	576 (−11%)
vec mat ops	2992	2664 (−11%)
field set	462	424 (−8%)
field get	414	450 (+9%)
nested method call	768	800 (+4%)
component / resource access	2452 / 2156	2559 / 2254 (+4%)
script system, query + iterate 1000	1.99 ms	1.29 ms (−35%)
script system, empty callback 1000	0.37 ms	1.23 ms (eager lists)

Things that behave differently

• Rust code inspecting returned ScriptValues gets Value for small types (one test updated).
• Functions taking a raw ScriptValue and matching only Reference silently miss values. Three are fixed: eq, EnumVariantRef::eq, trigger_event. Third-party code needs the same treatment (migration notes).
• A function that mutates a value passed as an argument, not as the receiver, via M<T> errors, or with a raw ReflectReference mutates a copy. No bindings in the repo do this.

Tests

• Lua + Rune with every binding feature: 325/325, including the new value_semantics tests (aliasing, copy on assignment, fields are places, equality between field references and values).
• Unit tests, LAD / docgen tests, clippy (workspace, lua54 + rune), and builds for luajit / luau / lua51 all pass.

🤖 Generated with Claude Code

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/bindings/bevy_mod_scripting_bevy_ecs_bindings/src/lib.rs	74% smaller
crates/bevy_mod_scripting_bindings/src/function/into.rs	60% smaller
assets/tests/add_system/system_with_parameters.lua	55% smaller
assets/tests/add_system/optional_components_and_disjoint_queries.lua	48% smaller
crates/bevy_mod_scripting_core/src/derive_tests/mod.rs	43% smaller
crates/bevy_mod_scripting_bindings/src/dispatch.rs	42% smaller
assets/tests/query/query_can_access_components.lua	41% smaller
crates/languages/bevy_mod_scripting_rune/src/value.rs	34% smaller
benches/benchmarks.rs	29% smaller
crates/languages/bevy_mod_scripting_lua/src/bindings/reference.rs	19% smaller
assets/scripts/game_of_life.lua	16% smaller
assets/tests/query/dynamic_component_query.lua	15% smaller
assets/tests/query/query_returns_all_entities_matching.lua	15% smaller
crates/bevy_mod_scripting_core/src/script_system.rs	15% smaller
assets/tests/add_system/read_only_parameters_cannot_be_written.lua	14% smaller
crates/bevy_mod_scripting_functions/src/core.rs	13% smaller
crates/languages/bevy_mod_scripting_rune/src/types.rs	9% smaller
crates/bevy_mod_scripting_bindings/src/query.rs	8% smaller
crates/bevy_mod_scripting_bindings/src/function/from.rs	6% smaller
assets/tests/add_system/system_cannot_access_component_outside_query_archetypes.lua	5% smaller
crates/bevy_mod_scripting_bindings/src/script_value.rs	1% smaller
assets/macro_benchmarks/script_systems/query_system.lua	0% smaller
assets/macro_benchmarks/script_systems/query_system_iterate.lua	0% smaller
assets/scripts/game_of_life.rn	Unsupported file format
assets/tests/add_system/system_with_parameters.rn	Unsupported file format
assets/tests/bindings/transform/value_semantics.lua	0% smaller
assets/tests/bindings/transform/value_semantics.rn	Unsupported file format
assets/tests/query/dynamic_component_query.rn	Unsupported file format
assets/tests/query/query_can_access_components.rn	Unsupported file format
assets/tests/query/query_returns_all_entities_matching.rn	Unsupported file format
assets/tests/script_callbacks/lua/script_callbacks.lua	0% smaller
assets/tests/script_callbacks/rune/script_callbacks.rn	Unsupported file format
crates/bevy_mod_scripting_bindings/src/function/from_ref.rs	0% smaller
crates/bevy_mod_scripting_bindings/src/inline_value.rs	0% smaller
crates/bevy_mod_scripting_bindings/src/lib.rs	0% smaller
crates/bindings/bevy_mod_scripting_bevy_input_bindings/src/focus.rs	0% smaller
crates/languages/bevy_mod_scripting_lua/src/bindings/script_value.rs	0% smaller
crates/testing_crates/script_integration_test_harness/src/lib.rs	0% smaller
docs/src/Development/AddingLanguages/necessary-features.md	Unsupported file format
docs/src/ReleaseNotes/0.23-to-0.24.md	Unsupported file format
docs/src/ScriptSystems/introduction.md	Unsupported file format

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Bencher Report

Project	Bevy Scripting
Branch	agent/script-systems-perf
Testbed	linux-gha

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