# git merges of tags 2 messages from 2017-05-18 to 2017-05-19. Participants: Stephen Rothwell, Linus Torvalds. Thread: https://gitlist.dev/t/46000 ## Stephen Rothwell, 2017-05-18 23:23 Subject: git merges of tags Message-ID: <20170519092202.6b0f9a57@canb.auug.org.au> URL: https://gitlist.dev/e/20170519092202.6b0f9a57%40canb.auug.org.au ``` Hi all, Just a reminder that if you are merging Linus' tree (or any tree really) via a tag, git was changed some time ago so that merging a tag will not do a fast forward (there is a good reason for this - I just can't recall it ATM). This is a problem when your current head of branch has been merged into (e.g.) Linus' tree and then you do "git merge " on a tag that is later than the merge point. You end up with an unnecessary merge commit rather than just fast forwarding. To do the fast forward, try "git merge ^{}" ... (unfortunately doing "git merge --ff " also does not do a fast forward - it also doesn't fail, it unexpectedly just creates a merge commit :-(). -- Cheers, Stephen Rothwell ``` ## Linus Torvalds, 2017-05-19 18:30 Subject: Re: git merges of tags Message-ID: URL: https://gitlist.dev/e/CA%2B55aFwaxsNZ0ACQkASdDTbSrdcHMJpFPtswK485tEWRBVVYrA%40mail.gmail.com In-Reply-To: <20170519092202.6b0f9a57@canb.auug.org.au> ``` On Thu, May 18, 2017 at 4:23 PM, Stephen Rothwell wrote: > > Just a reminder that if you are merging Linus' tree (or any tree > really) via a tag, git was changed some time ago so that merging a tag > will not do a fast forward (there is a good reason for this - I just > can't recall it ATM). The reason is that when you merge a signed tag, git squirrels away t he signature into the merge commit, so that you can see and verify the signage later (use "git log --show-signatures" to see the signatures on the commits). If you fast-forward, there isn't any new commit to add the signing data to. > To do the fast forward, try "git merge ^{}" ... A slightly simpler syntax might be just "tag^0", but yes, the "^{}" thing peels off any tags. > (unfortunately > doing "git merge --ff " also does not do a fast forward - it also > doesn't fail, it unexpectedly just creates a merge commit :-(). "--ff" is the default behavior, and means "allow fast forward", but note that it is about "allowing", not "forcing". You can use "--ff-only" to say that you will _only_ accept a fast-forward, and git will error out if it needs to create a merge. Linus ```