On 2021-04-19 at 09:11:12, Cristian Morales Vega wrote: > I thought you may want to take a look at > https://issues.jenkins.io/browse/JENKINS-65395. > > Basically after something updates the ctime of a file, a > "git checkout" can behave differently depending on whether a > "git update-index --refresh" has been run before or not. > _Maybe_ it could make sense for "git checkout" to always behave as if > "git update-index --refresh" had been run before? No idea really. I believe the situation you're seeing is that git checkout usually doesn't rewrite files in the working tree that are already up to date. This makes checkout much faster in large working trees. By default, Git does include the ctime in its computation of whether a file is up to date. If the ctime changes, then the file is considered to be stale. git checkout, without an intervening command, will overwrite it, since it's dirty and just overwriting it is cheaper than determining whether it is in fact up to date. git update-index --refresh does the check about whether the file is in fact up to date. This isn't free; if you've modified 1000 files, or if you've modified large files, there's going to be a cost to this, and it can be very substantial. As mentioned, git checkout doesn't want to perform that cost needlessly, so it overwrites the file unconditionally. As far as I'm aware, Git doesn't document which files it does and does not rewrite in the working tree as part of a checkout, except as part of certain specified options (e.g., the --overlay option). It is therefore free to choose any algorithm it chooses, and in this case, we've optimized for checkout performance, not minimal modifications. There is a config option, core.trustctime, which can be set to false if you don't want to consider the ctime as part of whether a file is up to date. But Git is behaving correctly and as desired here. -- brian m. carlson (he/him or they/them) Houston, Texas, US
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