Fix caching for unity builds - #5642
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joshua-spacetime
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jdetter
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July 31, 2026 21:35
jdetter
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Jul 31, 2026
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Seems fine, not tested manually by me
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Description of Changes
This is part of the work to break up #5612 into smaller reviewable chunks.
Before this change, the cache key for the unity library was
Unity-${{ github.head_ref }}. This meant every single PR experienced a cache miss, whether or not it changed any unity dependencies, and would subsequently do a full unity build and upload a new multi-GB entry to the actions cache. The actions cache isn't that big, so this was responsible for a huge amount of cache churn which in turn slowed all other builds down.Now the cache key incorporates the proper dependencies, and the cache is only written to on pushes to master.
API and ABI breaking changes
None
Expected complexity level and risk
1
Testing
N/A