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RE: [RFC PATCH 01/35] merge: improve fatal fast-forward message

From
Randall S. Becker <rsbecker@nexbridge.com>
Date
Jul 6, 2021, 21:27 UTC
Message-ID
<04df01d772ad$c9ac7430$5d055c90$@nexbridge.com>
In-Reply-To
<60e4c71099ef_1c4281208ad@natae.notmuch>
On July 6, 2021 5:12 PM, Felipe Contreras wrote:
Show 52 quoted lines
>Randall S. Becker wrote:
>> On July 6, 2021 4:40 PM, Felipe Contreras wrote:
>> >Subject: Re: [RFC PATCH 01/35] merge: improve fatal fast-forward
>> >message
>> >
>> >Ævar Arnfjörð Bjarmason wrote:
>> >>
>> >> On Mon, Jul 05 2021, Felipe Contreras wrote:
>> >>
>> >> > Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
>> >> > ---
>> >> >  builtin/merge.c | 2 +-
>> >> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >> >
>> >> > diff --git a/builtin/merge.c b/builtin/merge.c index
>> >> > a8a843b1f5..05e631229d 100644
>> >> > --- a/builtin/merge.c
>> >> > +++ b/builtin/merge.c
>> >> > @@ -1620,7 +1620,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
>> >> >  	}
>> >> >
>> >> >  	if (fast_forward == FF_ONLY)
>> >> > -		die(_("Not possible to fast-forward, aborting."));
>> >> > +		die(_("unable to fast-forward"));
>> >>
>> >> I read the existing message a bit more like "this makes no sense
>> >> anymore" (correct) and the latter more like "we encountered an error".
>> >
>> >I mean, this is the documentation of --ff-only:
>> >
>> >  With `--ff-only`, resolve the merge as a fast-forward when possible.
>> >  When not possible, refuse to merge and exit with a non-zero status.
>> >
>> >So if you do `git merge --ff-only` you are telling git: "I want you to exit with an error when the fast-forward is not possible".
>> >
>> >If you do:
>> >
>> >  % git merge --ff-only
>> >  fatal: Not possible to fast-forward, aborting.
>> >
>> >That "aborting" part is redundant; we know `git merge` should abort if the fast-forward is not possible, we explicitely told git to do that.
>>
>> `git merge` is a special operation where errors (conflicts, for one)
>> may leave the repository in a merge pending state where you
>> subsequently may have to use `git merge --abort` to reset the
>> situation or `git add` to continue. The `aborting` output makes it
>> clear that you do not have to do the `--abort` and *cannot* do the
>> `add` because there was an implicit `--abort` done resulting from the
>> failure.
>
>But this is not a `git merge`, this is a `git merge --ff-only`; they are different operations. There *never* is a need for `--abort` with `git
>merge --ff-only`.
Well, you know that and I know that, but having to explain this to every new git user who will operationally use git merge --ff-only within hours or days of their first clone is a different matter.
Show 8 quoted lines
>Anyway, the error message is meant for `git fast-forward` which definitely doesn't need any `--abort`.
>
>Initially I created a new variable to have a different error message for `git merge --ff-only` and `git fast-forward`, precisely to avoid
>changing the current error message of `git merge --ff-only` and thus avoid any inertial comments like this one. But then I thought there
>was no need to complicate the series when both can be improved at once.
>Apparently that's not the case.
>
>I guess I'll add it back.
Thanks. I understand the purpose here.
-Randall
Previous: Felipe ContrerasNext: Felipe Contreras
Message 12 of 53 in “git update: fix broken git pull”
  1. 00/35 git update: fix broken git pullFelipe Contreras, Jul 5, 2021
  2. 01/35 merge: improve fatal fast-forward messageFelipe Contreras, Jul 5, 2021
  3. Ævar Arnfjörð BjarmasonJul 6, 2021
  4. Felipe ContrerasJul 6, 2021
  5. Randall S. BeckerJul 6, 2021
  6. Junio C HamanoJul 6, 2021
  7. Felipe ContrerasJul 6, 2021
  8. Randall S. BeckerJul 6, 2021
  9. Junio C HamanoJul 6, 2021
  10. Randall S. BeckerJul 6, 2021
  11. Felipe ContrerasJul 6, 2021
  12. Randall S. BeckerJul 6, 2021
  13. Felipe ContrerasJul 6, 2021
  14. 02/35 merge: split cmd_merge()Felipe Contreras, Jul 5, 2021
  15. 03/35 fast-forward: add new builtinFelipe Contreras, Jul 5, 2021
  16. 04/35 doc: fast-forward: explain what it isFelipe Contreras, Jul 5, 2021
  17. 05/35 fast-forward: add advice for novicesFelipe Contreras, Jul 5, 2021
  18. Ævar Arnfjörð BjarmasonJul 6, 2021
  19. Felipe ContrerasJul 6, 2021
  20. 06/35 fast-forward: make the advise configurableFelipe Contreras, Jul 5, 2021
  21. 07/35 fast-forward: add help about merge vs. rebaseFelipe Contreras, Jul 5, 2021
  22. 08/35 update: new built-inFelipe Contreras, Jul 5, 2021
  23. 09/35 update: add options and usage skeletonFelipe Contreras, Jul 5, 2021
  24. 10/35 update: add --ff optionFelipe Contreras, Jul 5, 2021
  25. Ævar Arnfjörð BjarmasonJul 6, 2021
  26. Felipe ContrerasJul 6, 2021
  27. 11/35 update: add --merge modeFelipe Contreras, Jul 5, 2021
  28. Ævar Arnfjörð BjarmasonJul 6, 2021
  29. Felipe ContrerasJul 6, 2021
  30. 12/35 commit: support for multiple MERGE_MODEFelipe Contreras, Jul 5, 2021
  31. 13/35 merge: add --reverse-parents optionFelipe Contreras, Jul 5, 2021
  32. 14/35 update: reverse the order of parentsFelipe Contreras, Jul 5, 2021
  33. 15/35 update: fake a reverse order of parents in messageFelipe Contreras, Jul 5, 2021
  34. 16/35 update: add --rebase modeFelipe Contreras, Jul 5, 2021
  35. 17/35 update: add mode configuationFelipe Contreras, Jul 5, 2021
  36. 18/35 update: add per-branch mode configurationFelipe Contreras, Jul 5, 2021
  37. 19/35 pull: cleanup autostash checkFelipe Contreras, Jul 5, 2021
  38. 20/35 pull: trivial cleanupFelipe Contreras, Jul 5, 2021
  39. 21/35 pull: trivial whitespace style fixFelipe Contreras, Jul 5, 2021
  40. 22/35 pull: introduce --merge optionFelipe Contreras, Jul 5, 2021
  41. 23/35 rebase: add REBASE_DEFAULTFelipe Contreras, Jul 5, 2021
  42. 24/35 pull: move configuration fetchesFelipe Contreras, Jul 5, 2021
  43. 25/35 pull: show warning with --ff optionsFelipe Contreras, Jul 5, 2021
  44. 26/35 pull: add pull.modeFelipe Contreras, Jul 5, 2021
  45. 27/35 pull: add per-branch mode configurationFelipe Contreras, Jul 5, 2021
  46. 28/35 pull: add pull.mode=fast-forwardFelipe Contreras, Jul 5, 2021
  47. 29/35 pull: reorganize mode conditionalsFelipe Contreras, Jul 5, 2021
  48. 30/35 pull: add diverging advice on fast-forward modeFelipe Contreras, Jul 5, 2021
  49. 31/35 pull: improve --rebase and pull.rebase interactionFelipe Contreras, Jul 5, 2021
  50. 32/35 pull: improve default warningFelipe Contreras, Jul 5, 2021
  51. 33/35 pull: advice of future changesFelipe Contreras, Jul 5, 2021
  52. 34/35 FUTURE: pull: enable ff-only mode by defaultFelipe Contreras, Jul 5, 2021
  53. 35/35 !fixup FUTURE: pull: enable ff-only mode by defaultFelipe Contreras, Jul 5, 2021

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