merge-tree: add a --allow-unrelated-histories flag
Folks may want to merge histories that have no common ancestry; provide a flag with the same name as used by `git merge` to allow this. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Elijah Newren committed
Jun 18, 2022 at 00:20 UTC
7976721d171e17330486b403e868b594cd238295
3 files changed
+34
-2
Documentation/git-merge-tree.txt
+5
@@ -59,6 +59,11 @@ OPTIONS
59
default is to include these messages if there are merge
60
conflicts, and to omit them otherwise.
61
62
+--allow-unrelated-histories::
63
+ merge-tree will by default error out if the two branches specified
64
+ share no common history. This flag can be given to override that
65
+ check and make the merge proceed anyway.
66
+
67
[[OUTPUT]]
68
OUTPUT
69
------
builtin/merge-tree.c
+6
-1
@@ -399,6 +399,7 @@ enum mode {
399
400
struct merge_tree_options {
401
int mode;
402
+ int allow_unrelated_histories;
403
int show_messages;
404
int name_only;
405
};
@@ -434,7 +435,7 @@ static int real_merge(struct merge_tree_options *o,
435
* merge_incore_recursive in merge-ort.h
436
*/
437
merge_bases = get_merge_bases(parent1, parent2);
437
- if (!merge_bases)
438
+ if (!merge_bases && !o->allow_unrelated_histories)
439
die(_("refusing to merge unrelated histories"));
440
merge_bases = reverse_commit_list(merge_bases);
441
@@ -500,6 +501,10 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
501
&o.name_only,
502
N_("list filenames without modes/oids/stages"),
503
PARSE_OPT_NONEG),
504
+ OPT_BOOL_F(0, "allow-unrelated-histories",
505
+ &o.allow_unrelated_histories,
506
+ N_("allow merging unrelated histories"),
507
+ PARSE_OPT_NONEG),
508
OPT_END()
509
};
510
t/t4301-merge-tree-write-tree.sh
+23
-1
@@ -44,7 +44,13 @@ test_expect_success setup '
44
git checkout side3 &&
45
git mv numbers sequence &&
46
test_tick &&
47
- git commit -m rename-numbers
47
+ git commit -m rename-numbers &&
48
+
49
+ git switch --orphan unrelated &&
50
+ >something-else &&
51
+ git add something-else &&
52
+ test_tick &&
53
+ git commit -m first-commit
54
'
55
56
test_expect_success 'Clean merge' '
@@ -215,4 +221,20 @@ test_expect_success 'NUL terminated conflicted file "lines"' '
221
test_cmp expect actual
222
'
223
224
+test_expect_success 'error out by default for unrelated histories' '
225
+ test_expect_code 128 git merge-tree --write-tree side1 unrelated 2>error &&
226
+
227
+ grep "refusing to merge unrelated histories" error
228
+'
229
+
230
+test_expect_success 'can override merge of unrelated histories' '
231
+ git merge-tree --write-tree --allow-unrelated-histories side1 unrelated >tree &&
232
+ TREE=$(cat tree) &&
233
+
234
+ git rev-parse side1:numbers side1:greeting side1:whatever unrelated:something-else >expect &&
235
+ git rev-parse $TREE:numbers $TREE:greeting $TREE:whatever $TREE:something-else >actual &&
236
+
237
+ test_cmp expect actual
238
+'
239
+
240
test_done