In git, how does one revert a single file with merge conflicts in it?

In git, how does one revert a single file with merge conflicts in it?

[Alan Mackenzie]

Hello, Emacs.

I'm attempting to backport a bug fix from master to emacs-24, following
the procedure in .../admin/notes/git-workflow.

On doing
   $ git cherry-pick -xe <Commit Id>
, I get a half error message: "error: could not apply f3f7acc... ...".
Further investigation reveals that the cause is conflicts in a ChangeLog
file.  No surprises there.

So, how do I revert ChangeLog to get rid of the conflicts?  I've tried
   $ git checkout lisp/ChangeLog
, but this just gives the puzzling error message "error: path
'lisp/ChangeLog' is unmerged".  Isn't git great?

How do I revert a file in git?

TIA.

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: In git, how does one revert a single file with merge conflicts in it?

[Andreas Schwab]

Alan Mackenzie <acm@muc.de> writes:

> How do I revert a file in git?

Have you tried reading the manual?

git-checkout(1)

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: In git, how does one revert a single file with merge conflicts in it?

[Alan Mackenzie]

Evening, Andreas.

On Mon, Feb 02, 2015 at 02:22:32PM +0100, Andreas Schwab wrote:
> Alan Mackenzie <acm@muc.de> writes:

> > How do I revert a file in git?

> Have you tried reading the manual?

Many times, yes.  Not often with much success.

> git-checkout(1)

Not even this one.

> Andreas.

> -- 
> Andreas Schwab, SUSE Labs, schwab@suse.de

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: In git, how does one revert a single file with merge conflicts in it?

[Andreas Schwab]

Your case is explicitly and elaborately handled in the manual.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: In git, how does one revert a single file with merge conflicts in it?

[David Kastrup]

Andreas Schwab <schwab@suse.de> writes:

> Your case is explicitly and elaborately handled in the manual.

Man, time really flies.  It seems like the finals for "least helpful
answer on a mailing list" are coming up again.

How about replacing "the manual" with "somewhere"?  It's almost as
specific but more ominous.

> Andreas.

You don't say.

-- 
David Kastrup

Re: In git, how does one revert a single file with merge conflicts in it?

[Steinar Bang]

> On Mon, Feb 02, 2015 at 02:22:32PM +0100, Andreas Schwab wrote:
>> Alan Mackenzie <acm@muc.de> writes:

>> > How do I revert a file in git?

>> git-checkout(1)

git checkout sha1 path/to/file

In place of sha1 you could put a tag or a branch name.

Re: In git, how does one revert a single file with merge conflicts in it?

[Eli Zaretskii]

> Date: Mon, 2 Feb 2015 12:00:03 +0000
> From: Alan Mackenzie <acm@muc.de>
> 
> On doing
>    $ git cherry-pick -xe <Commit Id>
> , I get a half error message: "error: could not apply f3f7acc... ...".
> Further investigation reveals that the cause is conflicts in a ChangeLog
> file.  No surprises there.

I suggest that you install the git-merge-changelog program and
configure it as the merge driver for ChangeLog files.  Then the
probability of such conflicts will be very close to zero.

Re: In git, how does one revert a single file with merge conflicts in it?

[Alan Mackenzie]

Hi, Eli.

On Mon, Feb 02, 2015 at 06:05:26PM +0200, Eli Zaretskii wrote:
> > Date: Mon, 2 Feb 2015 12:00:03 +0000
> > From: Alan Mackenzie <acm@muc.de>

> > On doing
> >    $ git cherry-pick -xe <Commit Id>
> > , I get a half error message: "error: could not apply f3f7acc... ...".
> > Further investigation reveals that the cause is conflicts in a ChangeLog
> > file.  No surprises there.

> I suggest that you install the git-merge-changelog program and
> configure it as the merge driver for ChangeLog files.  Then the
> probability of such conflicts will be very close to zero.

Thanks, I didn't know about this program.  I'll see if I can get it
working in my git.

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: In git, how does one revert a single file with merge conflicts in it?

[Stefan Monnier]

>    $ git cherry-pick -xe <Commit Id>
> , I get a half error message: "error: could not apply f3f7acc... ...".
> Further investigation reveals that the cause is conflicts in a ChangeLog
> file.  No surprises there.

IIUC git did perform the merge, you simply have a file with a conflict
as a result.  If you visit the file in Emacs, it should show you the
conflicts and if once you've edited the file so as too remove the
conflict markers, upon saving the result, Emacs should mark the file as
"resolved" (which you can do manually with "git add lisp/ChangeLog").


        Stefan

Re: In git, how does one revert a single file with merge conflicts in it?

[Alan Mackenzie]

Hello, Stefan.

On Mon, Feb 02, 2015 at 12:40:04PM -0500, Stefan Monnier wrote:
> >    $ git cherry-pick -xe <Commit Id>
> > , I get a half error message: "error: could not apply f3f7acc... ...".
> > Further investigation reveals that the cause is conflicts in a ChangeLog
> > file.  No surprises there.

> IIUC git did perform the merge, you simply have a file with a conflict
> as a result.  If you visit the file in Emacs, it should show you the
> conflicts and if once you've edited the file so as too remove the
> conflict markers, upon saving the result, Emacs should mark the file as
> "resolved" (which you can do manually with "git add lisp/ChangeLog").

OK.  I think what confused me was me thinking that there shouldn't be
"another" ChangeLog entry for the backported patch, given that there's
already one for the original patch.  But the ChangeLogs in Emacs 24 are
not the same files as those in Emacs 25.  Hence there needs to be an
entry in both of them.

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).