From: Elijah Newren <newren@xxxxxxxxx>
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@xxxxxxxxx>
---
Documentation/git-merge-tree.txt | 5 +++++
builtin/merge-tree.c | 7 ++++++-
t/t4301-merge-tree-write-tree.sh | 24 +++++++++++++++++++++++-
3 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/Documentation/git-merge-tree.txt b/Documentation/git-merge-tree.txt
index 55bb7bc61c1..d35710c81d5 100644
--- a/Documentation/git-merge-tree.txt
+++ b/Documentation/git-merge-tree.txt
@@ -49,6 +49,11 @@ OPTIONS
default is to include these messages if there are merge
conflicts, and to omit them otherwise.
+--allow-unrelated-histories::
+ merge-tree will by default error out if the two branches specified
+ share no common history. This flag can be given to override that
+ check and make the merge proceed anyway.
+
OUTPUT
------
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index dc52cd02dce..cca5075d521 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -393,6 +393,7 @@ static int trivial_merge(const char *base,
struct merge_tree_options {
int mode;
+ int allow_unrelated_histories;
int show_messages;
int exclude_modes_oids_stages;
};
@@ -430,7 +431,7 @@ static int real_merge(struct merge_tree_options *o,
* merge_incore_recursive in merge-ort.h
*/
common = get_merge_bases(parent1, parent2);
- if (!common)
+ if (!common && !o->allow_unrelated_histories)
die(_("refusing to merge unrelated histories"));
for (j = common; j; j = j->next)
commit_list_insert(j->item, &merge_bases);
@@ -494,6 +495,10 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
&o.exclude_modes_oids_stages,
N_("list conflicted files without modes/oids/stages"),
PARSE_OPT_NONEG),
+ OPT_BOOL_F(0, "allow-unrelated-histories",
+ &o.allow_unrelated_histories,
+ N_("allow merging unrelated histories"),
+ PARSE_OPT_NONEG),
OPT_END()
};
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 1572f460da0..996bdfaab7d 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -38,7 +38,13 @@ test_expect_success setup '
>whatever/empty &&
git add numbers greeting whatever/empty &&
test_tick &&
- git commit -m other-modifications
+ git commit -m other-modifications &&
+
+ git switch --orphan unrelated &&
+ >something-else &&
+ git add something-else &&
+ test_tick &&
+ git commit -m first-commit
'
test_expect_success 'Content merge and a few conflicts' '
@@ -139,4 +145,20 @@ test_expect_success 'Check conflicted oids and modes without messages' '
test_cmp conflicted-file-info actual
'
+test_expect_success 'error out by default for unrelated histories' '
+ test_expect_code 128 git merge-tree --write-tree side1 unrelated 2>error &&
+
+ grep "refusing to merge unrelated histories" error
+'
+
+test_expect_success 'can override merge of unrelated histories' '
+ git merge-tree --write-tree --allow-unrelated-histories side1 unrelated >tree &&
+ TREE=$(cat tree) &&
+
+ git rev-parse side1:numbers side1:greeting side1:whatever unrelated:something-else >expect &&
+ git rev-parse $TREE:numbers $TREE:greeting $TREE:whatever $TREE:something-else >actual &&
+
+ test_cmp expect actual
+'
+
test_done
--
gitgitgadget
