patchgit-p4.py: fix --prepare-p4-only error with multiple commits

> From: Ben Keene <seraphire@gmail.com>
>
> When using git p4 submit with the --prepare-p4-only option, the program
> should prepare a single p4 changelist and notify the user that more
> commits are pending and then stop processing.
>
> A bug has been introduced by the p4-changelist hook feature that
> causes the program to continue to try and process all pending
> changelists at the same time.
>
> The function applyCommit should return True when applying the commit
> was successful and the program should continue. In the case of the
> --prepare-p4-only flag, the function should return False, alerting the
> caller that the program should not proceed with additional commits.
>
> Change the return value from True to False in the applyCommit function
> when git-p4 is executed with --prepare-p4-only flag.
>
> Signed-off-by: Ben Keene <seraphire@gmail.com>
> ---

> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-775%2Fseraphire%2Fseraphire%2Fp4-hook-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-775/seraphire/seraphire/p4-hook-v1
> Pull-Request: https://github.com/git/git/pull/775
>
>  git-p4.py | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/git-p4.py b/git-p4.py
> index b8b2a1679e7..d9ced1bf552 100755
> --- a/git-p4.py
> +++ b/git-p4.py
> @@ -1984,7 +1984,7 @@ def get_diff_description(self, editedFiles, filesToAdd, symlinks):
>          return (diff + newdiff).replace('\r\n', '\n')
>  
>      def applyCommit(self, id):
> -        """Apply one commit, return True if it succeeded."""
> +        """Apply one commit, return True if it should continue processing."""
>  
>          print("Applying", read_pipe(["git", "show", "-s",
>                                       "--format=format:%h %s", id]))
> @@ -2222,7 +2222,7 @@ def applyCommit(self, id):
>                          print("  " + f)
>                  print("")
>                  sys.stdout.flush()
> -                return True
> +                return False
>  
>              if self.edit_template(fileName):
>                  if not self.no_verify:
>
> base-commit: d61d20c9b413225793f8a0b491bbbec61c184e26

> From: Ben Keene <seraphire@gmail.com>
>
> When using git p4 submit with the --prepare-p4-only option, the program
> should prepare a single p4 changelist and notify the user that more
> commits are pending and then stop processing.
> ...

> ...
> Be aware - this change will fix the existing test error in t9807.23
> for --prepare-p4-only. However there is insufficent coverage for
> this flag.  If more than 1 commit is pending submission to P4, the
> method will properly prepare the P4 changelist, however it will
> still exit the application with an exitcode of 1.
>
> The current documentation does not define what the exit code should be
> in this condition.
> (See: https://git-scm.com/docs/git-p4#Documentation/git-p4.txt---prepare-p4-only)

>     git-p4.py: fix --prepare-p4-only error with multiple commits
>     
>     When using git p4 submit with the --prepare-p4-only option, the program
>     should prepare a single p4 changelist and notify the user that more
>     commits are pending and then stop processing.
>     
>     A bug has been introduced by the p4-changelist hook feature that causes
>     the program to continue to try and process all pending changelists at
>     the same time.
>     
>     The function applyCommit should return True when applying the commit was
>     successful and the program should continue. In the case of the
>     --prepare-p4-only flag, the function should return False, alerting the
>     caller that the program should not proceed with additional commits.
>     
>     Change the return value from True to False in the applyCommit function
>     when git-p4 is executed with --prepare-p4-only flag.

>  git-p4.py | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/git-p4.py b/git-p4.py
> index b8b2a1679e7..c4a4012bcc1 100755
> --- a/git-p4.py
> +++ b/git-p4.py
> @@ -2537,11 +2537,12 @@ def run(self, args):
>                  ok = self.applyCommit(commit)
>              if ok:
>                  applied.append(commit)
> -            else:
> -                if self.prepare_p4_only and i < last:
> -                    print("Processing only the first commit due to option" \
> -                          " --prepare-p4-only")

>                  if i < last:
>                      # prompt for what to do, or use the option/variable
>                      if self.conflict_behavior == "ask":
>
> base-commit: 07d8ea56f2ecb64b75b92264770c0a664231ce17

>
> "Ben Keene via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > ...
> > Be aware - this change will fix the existing test error in t9807.23
> > for --prepare-p4-only. However there is insufficent coverage for
> > this flag.  If more than 1 commit is pending submission to P4, the
> > method will properly prepare the P4 changelist, however it will
> > still exit the application with an exitcode of 1.
> >
> > The current documentation does not define what the exit code should be
> > in this condition.
> > (See: https://git-scm.com/docs/git-p4#Documentation/git-p4.txt---prepare-p4-only)
>
> Then some proposal to define what the behaviour should be is needed,
> the consensus implements and then documented.

>
> >
> > Signed-off-by: Ben Keene <seraphire@gmail.com>
> > ---
>
>
> >     git-p4.py: fix --prepare-p4-only error with multiple commits
> >
> >     When using git p4 submit with the --prepare-p4-only option, the program
> >     should prepare a single p4 changelist and notify the user that more
> >     commits are pending and then stop processing.
> >
> >     A bug has been introduced by the p4-changelist hook feature that causes
> >     the program to continue to try and process all pending changelists at
> >     the same time.
> >
> >     The function applyCommit should return True when applying the commit was
> >     successful and the program should continue. In the case of the
> >     --prepare-p4-only flag, the function should return False, alerting the
> >     caller that the program should not proceed with additional commits.
> >
> >     Change the return value from True to False in the applyCommit function
> >     when git-p4 is executed with --prepare-p4-only flag.
>
> This space below the three-dash-line is the best place to describe
> the difference between the previous version and this one.  It seems
> that the above text is not such a "here are what was bad/missing in
> v1 that got fixed/extended", or a copy of the log message (like many
> patches that come from GGG has).  I am a bit puzzled what it is, but
> for now let's pretend there wasn't any text below the three-dash-line
> and read on.
>
> >  git-p4.py | 9 +++++----
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/git-p4.py b/git-p4.py
> > index b8b2a1679e7..c4a4012bcc1 100755
> > --- a/git-p4.py
> > +++ b/git-p4.py
> > @@ -2537,11 +2537,12 @@ def run(self, args):
> >                  ok = self.applyCommit(commit)
> >              if ok:
> >                  applied.append(commit)
> > -            else:
> > -                if self.prepare_p4_only and i < last:
> > -                    print("Processing only the first commit due to option" \
> > -                          " --prepare-p4-only")
>
> So, it used to be that after failing to apply a commit, unless we
> are at the last step, we gave a message and left the loop under the
> prepare-p4-only mode.  We did not do anything special under the
> prepare-p4-only mode if applyCommit returned a success.
>
> > +                if self.prepare_p4_only:
> > +                    if i < last:
> > +                        print("Processing only the first commit due to option" \
> > +                                " --prepare-p4-only")
>
> Now, after successfully applying, we leave the loop under the
> prepare-p4-only mode.  We give the message only when we are not at
> the last step.
>
> >                      break
> > +            else:
>
> So..., what happens when the first step fails to apply and then the
> user tells us to skip the commit?  We'll go on to the next commit
> and then applyCommit() may say 'ok' this time around.  Does that
> count as "processed only the first commit and we are done"?
>
> >                  if i < last:
> >                      # prompt for what to do, or use the option/variable
> >                      if self.conflict_behavior == "ask":
> >
> > base-commit: 07d8ea56f2ecb64b75b92264770c0a664231ce17