Junio C Hamano <gitster@xxxxxxxxx> writes: >> Similarly, a script author could include >> >> git log -m --first-parent --format=%H -- README >> >> to filter the first-parent history for commits that modified README. >> The -m is a no-op but it reflects the script author's intent. > > So the expectation is with "-m" we'd give single parent commits on > the fp chain, and merges from side branches that change README, in > addition to merges from side branches that was forked way before the > README was updated on the trunk (hence had ancient README but the > merge kept the version from the trunk)? > >> For >> example, until 1e20a407fe2 (stash list: stop passing "-m" to "git >> log", 2021-05-21), "git stash list" did this. > > This is not a example that supports your conclusion, though. The > reason why 288c67ca (stash: default listing to working-tree diff, > 2014-08-06) added "-m" on the command line to make it: > > git log --format="%gd: %gs" -g --first-parent -m "$@" $ref_stash -- > > is to prepare for the users who may pass "-p" as part of the "$@"; > they wil get no patches out of these merge commits that represent > stash entries otherwise, and they'd have to pass "-m -p" instead, > without the change. > >> As a result, we can't safely change "-m" to imply "-p" without fear of >> breaking such scripts. Restore the previous behavior. > > So the above is *not* an example of a script that would have been > broken with this change. Sorry, I have to take 70% of the above back. While it is *not* an example that shows an author's intent that changes from not just trunk but all side branches to README are to be shown, the original left after 288c67ca (stash: default listing to working-tree diff, 2014-08-06) would have been broken by the change you are proposing to revert. It used to be just "if you give -p we'll show a patch" but if we make "-m" to mean "-m -p", it does get broken. Which is BAD. I am inclined to take the revert, but I do not think reverting it alone will break more things than it fixes. For example, 1e20a407 (stash list: stop passing "-m" to "git log", 2021-05-21) that dropped "-m" must be reverted as well, no?
