Re: Git difftool prints diff to console instead of launching difftool in v2.28

Hi,



this is my first bug report for git, I hope it's going to reach the right folks.



I just upgraded my Arch Linux (running in a VM) today, which came with a new version of git, 2.28, and I have noticed the difftool command stopped working properly.



In one concrete repository, for some commits only, I get this:


(3.8-one-nlu-dev) git:master 16.10. 23:01:02

matej@ac-mak-arch { ~/proj/one-sem/one-nlu-tools }

:; git difftool --tool=vimdiff HEAD^! | head

diff --cc one_nlu_tools/util/number_formatter.py

index b16931c,d2122ab..38ab1bb

--- a/one_nlu_tools/util/number_formatter.py

+++ b/one_nlu_tools/util/number_formatter.py

@@@ -1014,9 -1014,9 +1014,112 @@@ def format_italian_numbers(text, conver





  _REPLACEMENTS_PT = [  # {{{

++    ('noventa e nove', '99'),

++    ('noventa e oito', '98'),



(3.8-one-nlu-dev) git:master 16.10. 23:01:07

matej@ac-mak-arch { ~/proj/one-sem/one-nlu-tools }

:; git --version

git version 2.28.0



Where I would instead expect the usual prompts asking whether to run vimdiff, which works properly with git v2.27:



(3.8-one-nlu-dev) git:master 16.10. 23:01:42

matej@ac-mak-arch { ~/proj/one-sem/one-nlu-tools }

:; git difftool --tool=vimdiff HEAD^! | head



Viewing (1/2): 'one_nlu_tools/util/number_formatter.py'

^C



(3.8-one-nlu-dev) git:master 16.10. 23:02:37

matej@ac-mak-arch { ~/proj/one-sem/one-nlu-tools }

:; git --version

git version 2.27.0



I have some untracked files in the checkout currently, no intent-to-add entries as far as I can tell (I saw a single note in the changelog between v2.27..v2.28 that had to do with the difftool command and that talked about these intent-to-add entries):



(3.8-one-nlu-dev) git:master 16.10. 23:02:42

matej@ac-mak-arch { ~/proj/one-sem/one-nlu-tools }

:; git status

On branch master

Your branch is up to date with 'origin/master'.



Untracked files:

  (use "git add <file>..." to include in what will be committed)

        .tox-0/

        Session.vim

        mytest.py

        nose2.cfg

        tests/debugging_tests.py

        tests/resources/numbered_tags/

        unittest.cfg

        work/



nothing added to commit but untracked files present (use "git add" to track)





Please let me know what other information might be needed to investigate this issue.  Unfortunately, I couldn't subscribe to the git mailing list, it seems that our company servers include headers in the emails that Majordomo doesn't like. (And the bug report itself was rejected as spam, so I am trying to send it from Gmail now.)



Best,

                Matěj