Record per-file mtimes in .kati_stamp for accurate regen detection - #310
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Could you add a test? |
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| # Set mtime to a future timestamp (later than Kati's process start time). | ||
| # Previously, Kati compared file mtime against the generation start time, | ||
| # falsely marking files with mtime > gen_time as modified on subsequent runs. | ||
| touch -d "2030-01-01 00:00:00" dep.mk extra.txt |
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Could you do dates in like 2050 or later? I could see these tests breaking / becoming ineffective in 4 years.
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Updated the timestamp.
Previously, Kati recorded a single process start time (gen_time) in .kati_stamp and compared every makefile and extra file dependency against it during --regen check. This caused false invalidations in two common scenarios: 1. Virtual or on-demand filesystems where uncached source files are materialized on first read during evaluation, assigning them an mtime of TimeNow() which is later than Kati's start time. 2. Build-generated intermediate staging files written during Make evaluation with an mtime later than Kati's start time. On subsequent builds, Kati would see file.mtime > gen_time and falsely conclude that the files were modified, triggering unnecessary full reanalysis. This change stores each file's observed mtime alongside its path in .kati_stamp (both in ckati and rkati). During --regen, each file's current mtime is compared against its recorded mtime. If the file's mtime has not advanced, it is recognized as clean.
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Previously, Kati recorded a single process start time (gen_time) in .kati_stamp and compared every makefile and extra file dependency against it during --regen check.
This caused false invalidations in two common scenarios:
On subsequent builds, Kati would see file.mtime > gen_time and falsely conclude that the files were modified, triggering unnecessary full reanalysis.
This change stores each file's observed mtime alongside its path in .kati_stamp (both in ckati and rkati). During --regen, each file's current mtime is compared against its recorded mtime. If the file's mtime has not advanced, it is recognized as clean.