Add a Test Demonstrating Superfluous Cascading Across Module Boundaries #32122
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The idea is this: If we can have private intra-module dependencies, why not also have private inter-module dependencies. Currently, this is impossible because all edges from the CompilerInstance-level DependencyTracker are unconditionally registered as cascading. In addition, module loads are charged as depenendents to all files in a given batch, which means the exact set of external dependencies is some (non-deterministic) superset of the external dependencies of each files in the batch. This test case demonstrates one outcome of this approach: we recompile *way* too much when a dependent module changes.
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@swift-ci smoke test and merge |
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@swift-ci please test Windows platform |
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@swift-ci please smoke test Linux platform |
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⛵ |
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The idea is this: If we can have private intra-module dependencies, why
not also have private inter-module dependencies. Currently, this is
impossible because all edges from the CompilerInstance-level
DependencyTracker are unconditionally registered as cascading. In
addition, module loads are charged as depenendents to all files in
a given batch, which means the exact set of external dependencies is
some (non-deterministic) superset of all files in the batch.
This test case demonstrates one outcome of this approach: we recompile
way too much when a dependent module changes.