fix: avoid SDL3 target conflict when a system SDL3 is installed - #22
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find_package(SDL3) was followed by a check of INTERFACE_INCLUDE_DIRECTORIES on SDL3::SDL3 to decide whether the found package is usable. In the standard SDL3 package layout, SDL3::SDL3 is an alias of SDL3::SDL3-shared, which gets its include dirs transitively via SDL3::Headers instead of carrying them itself. The check therefore came back empty on e.g. Homebrew installs, SDL3 was fetched from source anyway, and its add_library(SDL3::Headers ALIAS ...) collided with the already-imported target: CMake Error: add_library cannot create ALIAS target "SDL3::Headers" because another target with the same name already exists. Trust the find_package result instead: fetch only when no SDL3::SDL3 target exists. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
MaxHeimbrock
requested review from
alan-george-lk,
stephen-derosa and
xianshijing-lk
as code owners
August 10, 2026 11:53
stephen-derosa
approved these changes
Aug 10, 2026
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Problem
Configuring the example collection fails on any machine with a system SDL3 install (e.g. Homebrew):
ExampleDeps.cmakecallsfind_package(SDL3 CONFIG QUIET)and then checksINTERFACE_INCLUDE_DIRECTORIESonSDL3::SDL3to decide whether the found package is usable. In the standard SDL3 package layout,SDL3::SDL3is an alias ofSDL3::SDL3-shared, which gets its include dirs transitively viaSDL3::Headersrather than carrying them itself. The property check therefore comes back empty, SDL3 gets fetched from source anyway, and the source build'sadd_library(SDL3::Headers ALIAS ...)collides with the target already imported from the system package.Fix
Trust the
find_packageresult: fetch SDL3 from source only when noSDL3::SDL3target exists.Testing
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