bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Fredrik Nyqvist]

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Hi,

I would like to use vc mode to edit an outgoing commit message.

Steps to reproduce:
1. emacs -Q /path/to/git/repo
2. Edit a file and then
3. Run vc-next-action to create a commit: C-x v v
4. Write a commit message and end with C-c C-c
5. Now Open the outgoing log (vc-log-outgoing) : C-x v O
6. Try to edit the commit message (log-view-modify-change-comment): e

This message is printed:

log-view-current-file: Unable to determine the current file


In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.5)
 of 2019-11-23 built on gnu
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bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Dmitry Gutov]

On 23.11.2019 12:01, Fredrik Nyqvist wrote:

> I would like to use vc mode to edit an outgoing commit message.
> 
> Steps to reproduce:
> 1. emacs -Q /path/to/git/repo
> 2. Edit a file and then
> 3. Run vc-next-action to create a commit: C-x v v
> 4. Write a commit message and end with C-c C-c
> 5. Now Open the outgoing log (vc-log-outgoing) : C-x v O
> 6. Try to edit the commit message (log-view-modify-change-comment): e
> 
> This message is printed:
> 
> log-view-current-file: Unable to determine the current file

Yes. This feature seems unfinished, and it was never updated for the 
newer VC systems.

However, we have an option for amending the last commit (press C-x C-e 
in an already open log-edit buffer). It only works with Git and Hg now.

It would be good to unify these two features somehow.

bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Fredrik Nyqvist]

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Yes, I have tried the option you mention to edit the last commit with C-x
C-e and it is working fine.
But It seems that it only allows amending the last commit if I have edited
a file.

As I understand it I need to edit a file and then do vc-next-action to get
to the log-edit buffer
where you can do C-x C-e.

I could not find a way to do this if just the commit message is supposed to
be updated.

Den mån 25 nov. 2019 kl 12:48 skrev Dmitry Gutov <dgutov@yandex.ru>:

> On 23.11.2019 12:01, Fredrik Nyqvist wrote:
>
> > I would like to use vc mode to edit an outgoing commit message.
> >
> > Steps to reproduce:
> > 1. emacs -Q /path/to/git/repo
> > 2. Edit a file and then
> > 3. Run vc-next-action to create a commit: C-x v v
> > 4. Write a commit message and end with C-c C-c
> > 5. Now Open the outgoing log (vc-log-outgoing) : C-x v O
> > 6. Try to edit the commit message (log-view-modify-change-comment): e
> >
> > This message is printed:
> >
> > log-view-current-file: Unable to determine the current file
>
> Yes. This feature seems unfinished, and it was never updated for the
> newer VC systems.
>
> However, we have an option for amending the last commit (press C-x C-e
> in an already open log-edit buffer). It only works with Git and Hg now.
>

It would be good to unify these two features somehow.
>

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bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Dmitry Gutov]

On 25.11.2019 22:16, Fredrik Nyqvist wrote:
> Yes, I have tried the option you mention to edit the last commit with 
> C-x C-e and it is working fine.
> But It seems that it only allows amending the last commit if I have 
> edited a file.

Yes. Not sure how to change an arbitrary commit in Git anyway (without 
interactive rebase). The best approximation looks like this:

https://stackoverflow.com/a/48999882/615245

> As I understand it I need to edit a file and then do vc-next-action to 
> get to the log-edit buffer
> where you can do C-x C-e.

Yes.

> I could not find a way to do this if just the commit message is supposed 
> to be updated.

And that is indeed the main downside of our current solution.

(The way to do it is to edit, call vc-next-action, then undo the edit in 
the file, but commit the amended message anyway. Which could be more 
efficient).

bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Fredrik Nyqvist]

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Den mån 25 nov. 2019 kl 23:49 skrev Dmitry Gutov <dgutov@yandex.ru>:

> On 25.11.2019 22:16, Fredrik Nyqvist wrote:
> > Yes, I have tried the option you mention to edit the last commit with
> > C-x C-e and it is working fine.
> > But It seems that it only allows amending the last commit if I have
> > edited a file.
>
> Yes. Not sure how to change an arbitrary commit in Git anyway (without
> interactive rebase). The best approximation looks like this:
>
> https://stackoverflow.com/a/48999882/615245


I am not sure how to do it in a good way either. Maybe the option to edit
an
older commit message could be skipped for vc-git. And then just allow amend
on the latest one.

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bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Dmitry Gutov]

On 26.11.2019 22:43, Fredrik Nyqvist wrote:
> Den mån 25 nov. 2019 kl 23:49 skrev Dmitry Gutov <dgutov@yandex.ru 
> <mailto:dgutov@yandex.ru>>:
> 
>     On 25.11.2019 22:16, Fredrik Nyqvist wrote:
>      > Yes, I have tried the option you mention to edit the last commit
>     with
>      > C-x C-e and it is working fine.
>      > But It seems that it only allows amending the last commit if I have
>      > edited a file.
> 
>     Yes. Not sure how to change an arbitrary commit in Git anyway (without
>     interactive rebase). The best approximation looks like this:
> 
>     https://stackoverflow.com/a/48999882/615245
> 
> 
> I am not sure how to do it in a good way either. Maybe the option to 
> edit an
> older commit message could be skipped for vc-git. And then just allow amend
> on the latest one.

The question is how to skip. Error in the end, after the user has 
already written the new commit message?

Or add a backend predicate action, like "can edit revision ##". That's 
one more action, though.

bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Fredrik Nyqvist]

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Den ons 27 nov. 2019 kl 01:10 skrev Dmitry Gutov <dgutov@yandex.ru>:

> On 26.11.2019 22:43, Fredrik Nyqvist wrote:
> > Den mån 25 nov. 2019 kl 23:49 skrev Dmitry Gutov <dgutov@yandex.ru
> > <mailto:dgutov@yandex.ru>>:
> >
> >     On 25.11.2019 22:16, Fredrik Nyqvist wrote:
> >      > Yes, I have tried the option you mention to edit the last commit
> >     with
> >      > C-x C-e and it is working fine.
> >      > But It seems that it only allows amending the last commit if I
> have
> >      > edited a file.
> >
> >     Yes. Not sure how to change an arbitrary commit in Git anyway
> (without
> >     interactive rebase). The best approximation looks like this:
> >
> >     https://stackoverflow.com/a/48999882/615245
> >
> >
> > I am not sure how to do it in a good way either. Maybe the option to
> > edit an
> > older commit message could be skipped for vc-git. And then just allow
> amend
> > on the latest one.
>
> The question is how to skip. Error in the end, after the user has
> already written the new commit message?
>
> Or add a backend predicate action, like "can edit revision ##". That's
> one more action, though.
>

If the user is trying to edit an older commit message from the log-buffer
(with log-view-modify-change-comment) I think an error message is good,
before writing the commit message ("can't edit revision ##"). I feel that
it will be more clear at least.

Also we should think about how to handle a commit that has already been
pushed. In this case I guess a force push is needed, but maybe that is not
good to hide. Maybe it is better to just allow edit on local commits then.

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bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Dmitry Gutov]

On 27.11.2019 22:11, Fredrik Nyqvist wrote:
> 
> 
> Den ons 27 nov. 2019 kl 01:10 skrev Dmitry Gutov <dgutov@yandex.ru 
> <mailto:dgutov@yandex.ru>>:
> 
>     On 26.11.2019 22:43, Fredrik Nyqvist wrote:
>      > Den mån 25 nov. 2019 kl 23:49 skrev Dmitry Gutov
>     <dgutov@yandex.ru <mailto:dgutov@yandex.ru>
>      > <mailto:dgutov@yandex.ru <mailto:dgutov@yandex.ru>>>:
>      >
>      >     On 25.11.2019 22:16, Fredrik Nyqvist wrote:
>      >      > Yes, I have tried the option you mention to edit the last
>     commit
>      >     with
>      >      > C-x C-e and it is working fine.
>      >      > But It seems that it only allows amending the last commit
>     if I have
>      >      > edited a file.
>      >
>      >     Yes. Not sure how to change an arbitrary commit in Git anyway
>     (without
>      >     interactive rebase). The best approximation looks like this:
>      >
>      > https://stackoverflow.com/a/48999882/615245
>      >
>      >
>      > I am not sure how to do it in a good way either. Maybe the option to
>      > edit an
>      > older commit message could be skipped for vc-git. And then just
>     allow amend
>      > on the latest one.
> 
>     The question is how to skip. Error in the end, after the user has
>     already written the new commit message?
> 
>     Or add a backend predicate action, like "can edit revision ##". That's
>     one more action, though.
> 
> 
> If the user is trying to edit an older commit message from the 
> log-buffer (with log-view-modify-change-comment) I think an error 
> message is good, before writing the commit message ("can't edit revision 
> ##"). I feel that it will be more clear at least.

Then it seems like we'd also have to introduce a new predicate backend 
action (like "can I edit this revision"). Given a recent discussion with 
our maintainer, I'm not confident we're allowed to do that.

> Also we should think about how to handle a commit that has already been 
> pushed. In this case I guess a force push is needed, but maybe that is 
> not good to hide. Maybe it is better to just allow edit on local commits 
> then.

Yeah, it's going to be a choice. Sometimes editing even a commit that's 
been pushed is okay (if it's on a personal branch). We already allow 
doing that with 'C-x C-e', so I'd rather we only gave out a warning 
(with yes-no prompt). The aforementioned predicate could do that job, too.

bug#38343: 27.0.50; vc git: Cannot edit outgoing log (like git commit --amend)

[Fredrik Nyqvist]

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Den ons 27 nov. 2019 kl 23:08 skrev Dmitry Gutov <dgutov@yandex.ru>:

> On 27.11.2019 22:11, Fredrik Nyqvist wrote:
> >
> >
> > Den ons 27 nov. 2019 kl 01:10 skrev Dmitry Gutov <dgutov@yandex.ru
> > <mailto:dgutov@yandex.ru>>:
> >
> >     On 26.11.2019 22:43, Fredrik Nyqvist wrote:
> >      > Den mån 25 nov. 2019 kl 23:49 skrev Dmitry Gutov
> >     <dgutov@yandex.ru <mailto:dgutov@yandex.ru>
> >      > <mailto:dgutov@yandex.ru <mailto:dgutov@yandex.ru>>>:
> >      >
> >      >     On 25.11.2019 22:16, Fredrik Nyqvist wrote:
> >      >      > Yes, I have tried the option you mention to edit the last
> >     commit
> >      >     with
> >      >      > C-x C-e and it is working fine.
> >      >      > But It seems that it only allows amending the last commit
> >     if I have
> >      >      > edited a file.
> >      >
> >      >     Yes. Not sure how to change an arbitrary commit in Git anyway
> >     (without
> >      >     interactive rebase). The best approximation looks like this:
> >      >
> >      > https://stackoverflow.com/a/48999882/615245
> >      >
> >      >
> >      > I am not sure how to do it in a good way either. Maybe the option
> to
> >      > edit an
> >      > older commit message could be skipped for vc-git. And then just
> >     allow amend
> >      > on the latest one.
> >
> >     The question is how to skip. Error in the end, after the user has
> >     already written the new commit message?
> >
> >     Or add a backend predicate action, like "can edit revision ##".
> That's
> >     one more action, though.
> >
> >
> > If the user is trying to edit an older commit message from the
> > log-buffer (with log-view-modify-change-comment) I think an error
> > message is good, before writing the commit message ("can't edit revision
> > ##"). I feel that it will be more clear at least.
>
> Then it seems like we'd also have to introduce a new predicate backend
> action (like "can I edit this revision"). Given a recent discussion with
> our maintainer, I'm not confident we're allowed to do that.
>
> OK I understand.


> > Also we should think about how to handle a commit that has already been
> > pushed. In this case I guess a force push is needed, but maybe that is
> > not good to hide. Maybe it is better to just allow edit on local commits
> > then.
>
> Yeah, it's going to be a choice. Sometimes editing even a commit that's
> been pushed is okay (if it's on a personal branch). We already allow
> doing that with 'C-x C-e', so I'd rather we only gave out a warning
> (with yes-no prompt). The aforementioned predicate could do that job, too.
>

That sounds good to me. At least so that log-view-modify-change-comment
works the same way as 'C-x C-e'.

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