Re: Feature Request: Allow to stash push and pop file modification times to avoid rebuilds

Ridil culous <reallyridilculous@gmail.com> writes:

It is very consistent with everything Git (the version control system) does to working tree files, e.g. "git restore -- file", "git switch branch". Like it or not, build systems that avoids recomputation of material derived from source files (which are kept in the version control systems, like Git) often work by comparing file timestamps.

Imagine that you had iffy changes in the working tree files, and then did a build. The build artifacts are based on the souce with those iffy changes. Then you do "stash push" to tentatively remove the changes. Perhaps you make a build again. You want your new build artifacts to reflect the fact that you no longer have those iffy changes in the source, so "stash push" should update the file timestamp when it removes the changes. Now you would do "stash pop", because you are convinced that those changes that you earlier thought were iffy are indeed good ones.

Now what timestamp should "stash pop" give to the working tree files in this case? The contents of the file probably is identical to the timestamp of the working tree files immediately before "stash push" was run. If we restore the original timestamp, because it is way older than the build artifacts of your second build (which was done after "stash push"), the build artifacts would not be recreated. The source has those changes (that used to be deemed iffy but now they are OK), the build artifact does not.

Unless your build system bases its rebuilding decisions on the contents, not timestamps, it is very much essential not to artificially muck with the file timestamp when your source control system rewrites the files in your working tree to avoid broken builds, I would have to say.