Fix cache issues with self-hosted runners #3879
                
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Summary
USE_SELF_HOSTEDrepository variable to detect when using self-hosted runnersProblem
As discussed in Slack, the caching fails on self-hosted runners because they don't clean slate between runs, so the depot already exists when the cache action tries to restore it.
Reference: https://github.com/SciML/ModelingToolkit.jl/actions/runs/16840335621/job/47712027510?pr=3869
Solution
Following Ian Butterworth's suggestion, this PR:
USE_SELF_HOSTEDrepository variableself-hosted: trueto the reusable workflow when the variable is setcache: false) for self-hosted runnersUsage
To use self-hosted runners, set the
USE_SELF_HOSTEDrepository variable to'true'in the repository settings.Test Plan
USE_SELF_HOSTED='true'to verify self-hosted runners work without cache errors🤖 Generated with Claude Code