checkout -m --conflict=diff3: add a label for ancestor

git checkout --merge --conflict=diff3 can be used to present conflict hunks including text from the common ancestor. The added information is helpful for resolving a merge by hand, and merge tools tend to understand it because it is very similar to what ‘diff3 -m’ produces. Unlike current git, diff3 -m includes a label for the merge base on the ||||||| line, and unfortunately, some tools cannot parse the conflict hunks without it. Humans can benefit from a cue when learning to interpreting the format, too. Mark the start of the text from the old branch with a label based on the branch’s name. git rerere does not have trouble parsing this output and its preimage ids are unchanged since it includes its own code for recreating conflict hunks. No other code in git tries to parse conflict hunks. Requested-by: Stefan Monnier <monnier@iro.umontreal.ca> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jonathan Nieder committed Mar 20, 2010 at 19:42 UTC c4151629e7019d072cefdac992e164820ce9ed1c

2 files changed +2 -1

builtin/checkout.c

@@ -439,6 +439,7 @@ static int merge_working_tree(struct checkout_opts *opts,

439 ret = reset_tree(new->commit->tree, opts, 1);

440 if (ret)

441 return ret;

442 + o.ancestor = old->name;

443 o.branch1 = new->name;

444 o.branch2 = "local";

445 merge_trees(&o, new->commit->tree, work,

t/t7201-co.sh

+1 -1

@@ -209,7 +209,7 @@ test_expect_success 'checkout --merge --conflict=diff3 <branch>' '

209 a

210 c

211 e

212 - |||||||

212 + ||||||| master

213 a

214 b

215 c