[clang][scan-deps] Add option to disable caching stat failures #11728
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jansvoboda11
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clang/unittests/Tooling/DependencyScanning/DependencyScannerTest.cpp
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While the source code isn't supposed to change during a build, in some environments it does. This adds an option that disables caching of stat failures, meaning that source files can be added to the build during scanning. This adds a `-no-cache-negative-stats` option to clang-scan-deps to enable this behavior. There are no tests for clang-scan-deps as there's no reliable way to do so from it. A unit test has been added that modifies the filesystem between scans to test it. Internally this uses an environment variable. `CLANG_SCAN_CACHE_NEGATIVE_STATS`: If this is set or set to 1 negative stat caching is enabled. If it's 0 then it's disabled. Negative stat caching is disabled by default.
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While the source code isn't supposed to change during a build, in some environments it does. This adds an option that disables caching of stat failures, meaning that source files can be added to the build during scanning.
This adds a
-no-cache-negative-statsoption to clang-scan-deps to enable this behavior. There are no tests for clang-scan-deps as there's no reliable way to do so from it. A unit test has been added that modifies the filesystem between scans to test it.Internally this uses an environment variable.
CLANG_SCAN_CACHE_NEGATIVE_STATS: If this is set or set to 1 negative stat caching is enabled. If it's 0 then it's disabled.Negative stat caching is disabled by default.