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Re: [PATCH 2/2] git-gui: support for diff3 conflict style

From
Bert Wesarg <bert.wesarg@googlemail.com>
Date
Sep 30, 2019, 12:17 UTC
Message-ID
<CAKPyHN3nOL6qy4RhwwHrh2m3EJuJ1-rt-8+0+=z2oJi96Nigpw@mail.gmail.com>
In-Reply-To
<20190929150406.s57pmb3dggfbcqhr@yadavpratyush.com>
Pratyush,
On Sun, Sep 29, 2019 at 5:04 PM Pratyush Yadav <me@yadavpratyush.com> wrote:
Show 8 quoted lines
>
> Hi Philip, Bert,
>
> Is there any way I can test this change? Philip, I ran the rebase you
> mention in the GitHub issue [0], and I get that '9c8cba6862abe5ac821' is
> an unknown revision.
>
> Is there any quick way I can reproduce this (maybe on a sample repo)?

The easiest way to produce a merge conflict, is to change the same line differently in two branches and try to merge them. I added a fast-import file to demonstrate this for you.

$ git init foo $ cd foo $ git fast-import <../conflict-merge.fi $ git reset --hard master $ git merge branch

this gets you into the conflict, probably the usual style. Which looks in liek this on the terminal:

@@@ -2,7 -2,7 +2,11 @@@ Lorem ipsum dolor sit amet, consectetu
  Sed feugiat nisl eget efficitur ultrices.
  Nunc cursus metus rutrum, mollis lorem vitae, hendrerit mi.
  Aenean vestibulum ante ac libero venenatis, non hendrerit orci pharetra.
++<<<<<<< HEAD
 +Proin bibendum purus ut est tristique, non pharetra dui consectetur.
++=======
+ Proin placerat leo malesuada lacinia lobortis.
++>>>>>>> branch
  Pellentesque aliquam libero et nisi scelerisque commodo.
  Quisque id velit sed magna molestie porttitor.
  Vivamus sed urna in risus molestie ultricies.
and this in git gui: https://kgab.selfhost.eu/s/gHHaQqowGp7mXEb

Git gui removes the '++' in front of the marker lines. It therefor already 'changes' the 'diff'. Though git-apply cannot handle such 'diffs' anyway.

To get the diff3 style do:

$ git merge --abort $ git -c merge.conflictStyle=diff3 merge branch

This is how it looks in the terminal now:
@@@ -2,7 -2,7 +2,13 @@@ Lorem ipsum dolor sit amet, consectetu
  Sed feugiat nisl eget efficitur ultrices.
  Nunc cursus metus rutrum, mollis lorem vitae, hendrerit mi.
  Aenean vestibulum ante ac libero venenatis, non hendrerit orci pharetra.
++<<<<<<< HEAD
 +Proin bibendum purus ut est tristique, non pharetra dui consectetur.
++||||||| merged common ancestors
++Proin in felis eu elit suscipit rhoncus vel ut metus.
++=======
+ Proin placerat leo malesuada lacinia lobortis.
++>>>>>>> branch
  Pellentesque aliquam libero et nisi scelerisque commodo.
  Quisque id velit sed magna molestie porttitor.
  Vivamus sed urna in risus molestie ultricies.

As you can see, there is not the usual 'I removed this, and added that' experience, everything is 'added'. Thus I inverted the pre-image to '--'. Here is how it looks in the gui: https://kgab.selfhost.eu/s/5c8Tosra7WRfjwJ

Show 72 quoted lines
> [0] https://github.com/git-for-windows/git/issues/2340
>
> On 25/09/19 10:38PM, Bert Wesarg wrote:
> > This adds highlight support for the diff3 conflict style.
> >
> > The common pre-image will be reversed to --, because it has been removed
> > and either replaced with ours or theirs side.
> >
> > Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com>
> > ---
> >  git-gui.sh   |  3 +++
> >  lib/diff.tcl | 22 ++++++++++++++++++++++
> >  2 files changed, 25 insertions(+)
> >
> > diff --git a/git-gui.sh b/git-gui.sh
> > index fd476b6..6d80f82 100755
> > --- a/git-gui.sh
> > +++ b/git-gui.sh
> > @@ -3581,6 +3581,9 @@ $ui_diff tag conf d_s- \
> >  $ui_diff tag conf d< \
> >       -foreground orange \
> >       -font font_diffbold
> > +$ui_diff tag conf d| \
> > +     -foreground orange \
> > +     -font font_diffbold
> >  $ui_diff tag conf d= \
> >       -foreground orange \
> >       -font font_diffbold
> > diff --git a/lib/diff.tcl b/lib/diff.tcl
> > index 0fd4600..6caf4e7 100644
> > --- a/lib/diff.tcl
> > +++ b/lib/diff.tcl
> > @@ -347,6 +347,7 @@ proc start_show_diff {cont_info {add_opts {}}} {
> >       }
> >
> >       set ::current_diff_inheader 1
> > +     set ::conflict_state {CONTEXT}
> >       fconfigure $fd \
> >               -blocking 0 \
> >               -encoding [get_path_encoding $path] \
> > @@ -450,10 +451,28 @@ proc read_diff {fd conflict_size cont_info} {
> >                       {++} {
> >                               set regexp [string map [list %conflict_size $conflict_size]\
> >                                                               {^\+\+([<>=]){%conflict_size}(?: |$)}]
> > +                             set regexp_pre_image [string map [list %conflict_size $conflict_size]\
> > +                                                             {^\+\+\|{%conflict_size}(?: |$)}]
> >                               if {[regexp $regexp $line _g op]} {
> >                                       set is_conflict_diff 1
> >                                       set line [string replace $line 0 1 {  }]
> > +                                     set markup {}
> >                                       set tags d$op
> > +                                     switch -exact -- $op {
> > +                                     < { set ::conflict_state {OURS} }
> > +                                     = { set ::conflict_state {THEIRS} }
> > +                                     > { set ::conflict_state {CONTEXT} }
> > +                                     }
> > +                             } elseif {[regexp $regexp_pre_image $line]} {
> > +                                     set is_conflict_diff 1
> > +                                     set line [string replace $line 0 1 {  }]
> > +                                     set markup {}
> > +                                     set tags d|
> > +                                     set ::conflict_state {BASE}
> > +                             } elseif {$::conflict_state eq {BASE}} {
> > +                                     set line [string replace $line 0 1 {--}]
> > +                                     set markup {}
> > +                                     set tags d_--
>
> I'm afraid I don't follow what this hunk is supposed to do.
>
> You set the variable ::conflict_state to the values like OURS, THEIRS,
> CONTEXT, but I don't see those values being used anywhere. A quick
> search for these words shows me that you only set them, never read them.
the last elseif depends on it.

I actually only need to detect the pre-image lines, which starts with the ||| conflict-marker and ends with the === conflict-marker, instead of all possible states.

Show 6 quoted lines
>
> Is there some extra code that you have and I don't?
>
> Also, this function is long and complicated already. A comment
> explaining what this code is doing would be nice, since it is not at all
> obvious at first read-through.
Will re-send.
Bert
Show 21 quoted lines
>
> >                               } else {
> >                                       set tags d_++
> >                               }
> > @@ -505,6 +524,9 @@ proc read_diff {fd conflict_size cont_info} {
> >                       }
> >               }
> >               set mark [$ui_diff index "end - 1 line linestart"]
> > +             if {[llength $markup] > 0} {
> > +                     set tags {}
> > +             }
> >               $ui_diff insert end $line $tags
> >               if {[string index $line end] eq "\r"} {
> >                       $ui_diff tag add d_cr {end - 2c}
> > --
> > 2.21.0.789.ga095d9d866
> >
>
> --
> Regards,
> Pratyush Yadav
Previous: Pratyush YadavNext: Philip Oakley
Message 4 of 9 in “git-gui: use existing interface to query a path's attribute”
  1. 1/2 git-gui: use existing interface to query a path's attributeBert Wesarg, Sep 25, 2019
  2. 2/2 git-gui: support for diff3 conflict styleBert Wesarg, Sep 25, 2019
  3. Pratyush YadavSep 29, 2019
  4. Bert WesargSep 30, 2019
  5. Philip OakleyOct 3, 2019
  6. Pratyush YadavOct 3, 2019
  7. Philip OakleyOct 3, 2019
  8. Pratyush YadavSep 27, 2019
  9. Philip OakleyOct 4, 2019

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