Originally, with no base, Git gave P4Merge $LOCAL as a dummy base:
p4merge "$LOCAL" "$LOCAL" "$REMOTE" "$MERGED"
Commit 0a0ec7bd changed this to:
p4merge "empty file" "$LOCAL" "$REMOTE" "$MERGED"
to avoid the problem of being unable to save in some circumstances with
similar inputs.
Unfortunately this approach produces much worse results on differing
inputs. P4Merge really regards the blank file as the base, and once you
have just a couple of differences between the two branches you end up
with one a massive full-file conflict. The 3-way diff is not readable,
and you have to invoke "difftool MERGE_HEAD HEAD" manually to get a
useful view.
The original approach appears to have invoked special 2-way merge
behaviour in P4Merge that occurs only if the base filename is "" or
equal to the left input. You get a good visual comparison, and it does
not auto-resolve differences. (Normally if one branch matched the base,
it would autoresolve to the other branch).
But there appears to be no way of getting this 2-way behaviour and being
able to reliably save. Having base==left appears to be triggering other
assumptions. There are tricks the user can use to force the save icon
on, but it's not intuitive.
So we now follow a suggestion given in the original patch's discussion:
generate a virtual base, consisting of the lines common to the two
branches. This is the same as the technique used in resolve and octopus
merges, so we relocate that code to a shared function.
Note that if there are no differences at the same location, this
technique can lead to automatic resolution without conflict, combining
everything from the 2 files. As with the other merges using this
technique, we assume the user will inspect the result before saving.
Signed-off-by: Kevin Bracey <kevin@bracey.fi>
Reviewed-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Git - the stupid content tracker
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"git" can mean anything, depending on your mood.
- random three-letter combination that is pronounceable, and not
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- stupid. contemptible and despicable. simple. Take your pick from the
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Git is a fast, scalable, distributed revision control system with an
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Git is an Open Source project covered by the GNU General Public
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Please read the file INSTALL for installation instructions.
See Documentation/gittutorial.txt to get started, then see
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If git has been correctly installed, then the tutorial can also be
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documentation of each command with "man git-commandname" or "git help
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CVS users may also want to read Documentation/gitcvs-migration.txt
("man gitcvs-migration" or "git help cvs-migration" if git is
installed).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
The user discussion and development of Git take place on the Git
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To subscribe to the list, send an email with just "subscribe git" in
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