Implement component inheritance as a storage feature#2113

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SanderMertens wants to merge 21 commits into

component_inheritance_storage

SanderMertens commented May 27, 2026 •

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This PR makes component inheritance work for most flecs APIs, in addition to queries (which already works):

world.component<Base>();
world.component<Foo>().is_a<Base>();
world.component<Bar>().is_a<Base>();

flecs::entity e = world.entity("e")
  .add<Foo>()
  .add<Bar>();

e.has<Base>(); // true
Base& b = e.get<Base>(); // returns first matching

This PR implements the following changes:

sink component inheritance into the storage, so it becomes available for all APIs
get, has, owns, each now work with inheritance
queries for inherited components are now cacheable
queries for inherited components now use the correct stride when matching a derived type
inheritance support is added to reflection, so types can inherit from each other

SanderMertens force-pushed the component_inheritance_storage branch 14 times, most recently from 6230716 to 9dd433c Compare

May 28, 2026 06:30

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src/query/engine/engine.h Outdated

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include/flecs/addons/cpp/delegate.hpp

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src/query/engine/eval.c Outdated

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src/storage/table.c Outdated

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src/iter.c

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src/observable.c Outdated

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test/core/src/ComponentInheritance.c

SanderMertens force-pushed the component_inheritance_storage branch 2 times, most recently from b4e55ec to 9a70cff Compare

May 29, 2026 01:23

SanderMertens force-pushed the master branch 2 times, most recently from 3ca6d73 to e3f4d11 Compare

May 29, 2026 16:32

SanderMertens force-pushed the component_inheritance_storage branch from 0e37ca0 to 2edca0d Compare

May 29, 2026 20:35

SanderMertens force-pushed the component_inheritance_storage branch 2 times, most recently from 3c16945 to 2958db0 Compare

June 12, 2026 00:03


          [core] Implement component inheritance as storage feature

9281f66

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examples/cpp/queries/component_inheritance/src/main.cpp

+                  float value;
+              };
+              struct HealthBuf : Buf { };

SanderMertens Jun 12, 2026 •

edited

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Create types that add members on top of the base type (same for C example).

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src/query/engine/eval.c

-                  if (!redo || (op_ctx->remaining <= 0)) {
+              repeat: {
+                  bool next_table = !redo;
+                  if (redo) {

SanderMertens Jun 12, 2026

Owner Author

This code should not be necessary since flecs_query_next_column uses ecs_search, which supports inheritance.

SanderMertens added 19 commits

June 12, 2026 10:20


          Implement reflection support for inheritance

a315de6


          Code cleanup

c2c28af


          Improve binary size of C++ component inheritance support classes

7bda035


          Don't allow for changing IsA relationships for components that are in…

1fa702b

… use


          Move detection of IsA graph changes to observer

bc82247


          Code cleanup

8bfacd8


          Fix issue where observer with only optional terms would not correctly…

0b96d99

… set column index


          Fix crash in struct member cycle detection when member type is not alive

3c5492d


          Fix crash when serializing JSON for query that matches inherited comp…

f1216a9

…onent


          Add component inheritance examples

ecfcd3a


          Make component inheritance queries cacheable

9ab7e20


          [core] Invalidate reachable cache in flecs_actions_delete_tree even w…

ba03bd1

…hen diff->removed_flags is empty


          [core] Prevent pairs with DontFragment target from ending up in table…

f4b8844

… type


          [core] Improve construction of base component registration for tables

7ca18a8


          [query] Set DontFragment term flag for pairs with DontFragment target

923b5af


          [queries] Fix missed inherited matches and wrong shared field stride …

90324bc

…for derived components


          [core] Improve performance of ecs_search

c9571a6


          [query] Fix uninitialized variable warning in flecs_query_select_w_id

ea9251d


          [core] Fix component inheritance bugs in traversal, query validator a…

a057b2a

…nd script vars

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src/bootstrap.c

                   return;
               }
+              static

SanderMertens Jun 12, 2026

Owner Author

A global observer on IsA pairs is expensive. Move this to component record creation.


          Cleanup code

b118d50

SanderMertens force-pushed the component_inheritance_storage branch from 1860547 to b118d50 Compare

June 12, 2026 17:51

SanderMertens moved this to In progress in Flecs 4.2

SanderMertens added this to Flecs 4.2

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