Flecs v4.0.1

Highlights

Lots of performance improvements! 🚀

• Queries for sparse components are up to 20x faster
• get, get_mut, has and owns are 1.5-3x faster
• Cached queries are 5x faster to create, and match 1.5x faster with new tables
• Simple uncached queries are up to 2x faster than v4.0.0 (5x faster than v3.2.12)

Release notes

This version includes the following bugfixes:

• [cpp] Fix crash when copying world object during shutdown (thanks @jpeletier!)
• [cpp] Call populate_self recursively for simple query results (thanks @Indra-db!)
• [core] Fix assert when toggling component from stage
• [core] Fix command batching issue that could prevent query rematching
• [core] Fix issues with commands for sparse components
• [core] Fix issue with cloning named entities
• [core] Fix assert when calling emplace after remove while deferred
• [queries] Fix issue with not operator, traversal and wildcards
• [queries] Fix issue with toggleable components and terms with #0 source
• [queries] Fix issue with up traversal and (re)matching empty tables
• [observers] Fix issue with updating observers to different callback kind
• [observers] Fix issue with observer for sparse component (thanks @Megafunk!)
• [systems] Fix issue with updating system to different callback kind
• [script] Fix issue where anonymous entities wouldn't clear after script update
• [script] Fix syntax error for scripts with only a using statement
• [script] Fix issue where unresolved component in template didn't throw an error
• [script] Fix issue with anonymous template instance creation
• [script] Fix issues with partial component assignments
• [script] Fix issues with assigning non-trivial components
• [json] Fix issues in new deserializer, serialize full paths by default
• [json] Fix issue with serializing entity to JSON from stage
• [json] Fix issues with serializing sparse components
• [json] Fix issue with serializing inherited components without reflection data
• [rest] Ensure REST HTTP server always has valid delta_time value
• [rest] Only enable time measurements when OS time API is initialized

This version includes the following improvements:

• [cpp] Add flecs::ref<T> constructor that just takes an entity (thanks @RoyAwesome!)
• [cpp] Add support for iterating sparse component queries with run callback
• [core] Remove id and size fields from ecs_column_t
• [core] Use one size/count member for all table columns
• [core] Add component_map to tables to improve get/get_mut/has/owns performance
• [core] Improve performance of ecs_table_get_*_index functions
• [queries] Add dedicated iterator mode for queries that are fully cached
• [queries] Add dedicated iterator mode for queries that are fully trivial
• [queries] Don't evaluate first term of uncached queries twice
• [queries] Reduce branching in trivial iterator code
• [queries] Remove iterator mode that returned entities one by one
• [queries] Replace ecs_iter_t::columns with table records array
• [queries] Remove ecs_iter_t::ptrs
• [queries] Reduce number of observers created per query
• [queries] Reuse static sources/ids arrays for cached results where possible
• [queries] Don't generate query plan for trivial queries
• [queries] Implement fast query validation for simple queries
• [meta] Add option to provide 0 offset without triggering automatic offset computation (thanks @Indra-db!)
• [script] Suppress variable shadowing warning for parser on msvc
• [json] Remove legacy (v3) deserializer
• [log] Fix incorrect log color comparison (thanks @kagetu!)
• [docs] Replace no_readonly with immediate in system manual
• [docs] Fix link to migration guide
• [docs] Fix grammar in Rust query examples (thanks @waywardmonkeys!)
• [docs] Fix find/replace typos (thanks @waywardmonkeys!)
• [docs] Remove references to EcsIteratble (thanks @waywardmonkeys!)
• [misc] Create .gitattributes to preserve line endings on Windows (thanks @epreston!)
• [ci] Prevent running workflows concurrently for same branch

Benchmark results
https://github.com/SanderMertens/ecs_benchmark/tree/bda57ec04f1cb9ebeacab8a17cf9a0c3353d267b

Breaking changes

• Query results with inherited components now must be explicitly handled in C API (#466 (comment))
• Sparse components must now be obtained with ecs_field_at (#466 (comment))
• The columns/ptrs members got removed from iterators (#466 (comment))
• Member target query results have changed (#466 (comment))

New Contributors

• @epreston made their first contribution in #1294
• @Megafunk made their first contribution in #1299

Full Changelog: v4.0.0...v4.0.1