From: Ævar Arnfjörð Bjarmason Date: Thu, 30 Aug 2018 14:52:03 GMT Subject: Re: [PATCH v2 06/10] push doc: correct lies about how push refspecs work Message-ID: <87o9djdi0c.fsf@evledraar.gmail.com> In-Reply-To: On Tue, Jul 31 2018, Junio C Hamano wrote: I'm finally getting to re-rolling this. Just some inline comments. > Ævar Arnfjörð Bjarmason writes: > >> The is often the name of the branch you would want to push, but >> -it can be any arbitrary "SHA-1 expression", such as `master~4` or >> -`HEAD` (see linkgit:gitrevisions[7]). >> +it can be any arbitrary expression to a commit, such as `master~4` or >> +`HEAD` (see linkgit:gitrevisions[7]). It can also refer to tag >> +objects, trees or blobs if the is outside of `refs/heads/*`. > > "It can also refer to..." is a good addition, but do you really want > to make it part of this series to change/deprecate "SHA-1 expression" > (which would certainly involve discussion on "then what to call them > instead, now we are trying to refrain from saying SHA-1?")? I won't change that. >> +on the remote side. Whether this is allowed depends on where in >> +`refs/*` the reference lives. The `refs/heads/*` namespace will >> +only accept commit objects, and then only they can be >> +fast-forwarded. The `refs/tags/*` namespace will accept any kind of >> +object, and any changes to them and others types of objects will be >> +rejected. Finally, it's possible to push any type of object to any >> +namespace outside of `refs/{tags,heads}/*`, > > All sound correct. > >> but these will be treated >> +as branches for the purposes of whether `--force` is required, even in >> +the case where a tag object is pushed. > > I am not sure what "will be treated as branches" exactly means. > Does it mean "as if they were in refs/heads/* hierarchy?" Or > something else? I'll clarify this. Have rewritten most of this. >> That tag object will be >> +overwritten by another tag object (or commit!) without `--force` if >> +the new tag happens to point to a commit that's a fast-forward of the >> +commit it replaces. > > Yup, and that is something we want to fix with a later part of this > series. > For what it's worth this is not at all what I'm fixing. The new docs describe this better, but what I'm talking about here is that you can push a tag like git.git's v2.18.0 to refs/blah/my-tag, then you can push v2.19.0-rc0^{} to refs/blah/my-tag and it'll be allowed as a fast-forward, and then v2.19.0-rc1 etc. I.e. the non-refs/{tags,heads}/* update logic treats all updates to tags/commits as branch updates. We just look at the tag v2.18.0, see you want to replace it with the commit v2.19.0-rc0^{} and see "oh, that's a fast-forward". Arguably that should be changed, but I won't do that in this series. >> +By having the optional leading `+` to a refspec (or using `--force` >> +command line option) you can tell Git to update the ref even if >> +it is not allowed by its respective namespace clobbering rules (e.g., >> +it is not a fast-forward. in the case of `refs/heads/*` updates). > > This gives an impression that with "--force" you can put non-commit > inside refs/heads/* hierarchy. Is that correct (if so we probably > would want to fix that behaviour)? I'll fix the wording, but nope, luckily you can't do that. >> +This >> +does *not* attempt to merge into . See EXAMPLES below for >> +details. > > That is not wrong per-se, but would normal people expect a merge to > happen upon pushing on the other side, I wonder? > > Thanks for cleaning up our longstanding mess. Will fix/reword.