Why doesn't gitk highlight commit references from git-describe?

Hi,

If I look at git commit 89ea90351dd32fbe384d0cf844640a9c55606f3b in gitk, it does not linkify the v1.6.0-rc0~120^2 in the commit message.

Is there any reason for that, or can gitk be changed?

Thanks,

Steve.

On Wed, Apr 13, 2016 at 1:36 PM, Stephen Kelly <steveire@gmail.com> wrote:

Sure it can be changed. Go for it.

I think it is hard though. So for example it is easy to spot sha1s and link them (see a6ee883b8e as an example picking up ebef7e5 as a link.)

How would you know(/code) that v1.6.0-rc0~120^2 is a text worth linking? "v1.6.0-rc0" is a custom string as that is how we name tags in this project. It can follow any convention in other projects.

Maybe a first approximation is if there is a `~` followed by numbers or a ^ character, inspect the whole thing if it is a reference into the history?

(Special case for git.git: Sometimes in a discussion you want to explain stuff and may use HEAD^ or such to demonstrate the use case. Other projects would not use that as much in descriptive text I would assume. So we'd need to make sure changing refs (i.e. branches, symbolic refs such as HEAD, FETCH_HEAD) are not considered worth linkifying.)

Thanks, Stefan

Stefan Beller <sbeller@google.com> writes:

You (as a gitk process running in a repository) know what tags are in your repository, so you can find the above pattern and see if the prefix matches any of the known tag. That way, you do not have to worry about having to special case HEAD etc.

On Wed, Apr 13, 2016 at 2:32 PM, Junio C Hamano <gitster@pobox.com> wrote:

Sorry for shooting from the hip here[1], that thought was

But it should not be just tags?

We also want to have 4b9ab0ee0130~1^2 to work `right`, in the sense that not just the hexadecimals are highlighted and linking to 4b9ab0ee0130, but the whole expression should link to 49e863b02ae177.

[1] My thinking was just like in https://xkcd.com/761/

Stephen Kelly:

right, just tags should work I'd expect.

As said I was thinking about the git development, so see 5f3c3a4e6f11deda for an example:

    files_log_ref_write: new function

    Because HEAD and stash are per-worktree, every refs backend needs to
    go through the files backend to write these refs.

    So create a new function, files_log_ref_write, and add it to
    refs/refs-internal.h. Later, we will use this to handle reflog updates
    for per-worktree symbolic refs (HEAD).

I do not think we would want to link HEAD to anything in that example. (I'd have no idea what it would link to here, so just not link it?)

Thanks, Stefan

Stefan Beller <sbeller@google.com> writes:

I'd consider that just "crazy", though. I'd be just happy to see 4b9ab0ee0130 highlighted and lead to the named commit, i.e. as long as ~1^2 is not part of the link, it is sufficient.

Stefan Beller wrote:

Presumably the same logic which finds 4b9ab0ee0130 to link it can also see if it is suffixed with '~1^2' ?

Is a ref like 4b9ab0ee0130~1^2 commonly useful? In cmake we use the output of cmake describe --contains (when there is a following tag) to refer to commits, in a pattern which I've also seen in git.git occasionally:

 https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=23f3798c

I think the only reason for using the output of cmake describe --contains is that it shows the reader the 'era' of the commit (and release it appears in) without having to look it up. I'm not really aware of another good reason to use it, but I think that's enough to make sense.

However I'm not sure I understand why anyone would refer to 4b9ab0ee0130~1^2 instead of 49e863b0 (or perhaps v2.6.5~12, depending on whether the tag is there).

Right, so if a commit message contains something like 

 Make git rebase -i HEAD^^^^ ten times better

then HEAD^^^^ shouldn't become a link. Makes sense to me.

Thanks,

Steve.

Stephen Kelly wrote:

Oops, I mean git describe --contains of course.

Thanks,

Steve.

Stefan Beller wrote:

Would it be possible to implement linking for <tagname> optionally followed by something like that? Just tags should be links too, right?

What does 'HEAD^' mean? If it is 'the commit before this one', then why not link it?

Thanks,

Steve.