From: Kyle Zhao <kylezhao@xxxxxxxxxxx>
This option allows users to specify a merge-base commit for the merge.
It will give our callers more flexibility to use the `git merge-tree`.
For example:
git merge-tree --merge-base=<sha1>^1 source-branch <sha1>
This allows us to implement `git cherry-pick` in bare repositories.
Signed-off-by: Kyle Zhao <kylezhao@xxxxxxxxxxx>
---
merge-tree.c: add --merge-base= option
Thanks for Elijah's work. I'm very excited that merge-ort is integrated
into the git merge-tree, which means that we can use merge-ort in bare
repositories to optimize merge performance.
In this patch, I introduce a new --merge-base=<commit> option to allow
callers to specify a merge-base for the merge. This may allow users to
implement git cherry-pick and git rebase in bare repositories with git
merge-tree cmd.
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1397%2Fkeyu98%2Fkz%2Fmerge-tree-option-merge-base-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1397/keyu98/kz/merge-tree-option-merge-base-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1397
Documentation/git-merge-tree.txt | 4 +++
builtin/merge-tree.c | 23 +++++++++++++----
t/t4301-merge-tree-write-tree.sh | 44 ++++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+), 5 deletions(-)
diff --git a/Documentation/git-merge-tree.txt b/Documentation/git-merge-tree.txt
index d6c356740ef..e762209b76d 100644
--- a/Documentation/git-merge-tree.txt
+++ b/Documentation/git-merge-tree.txt
@@ -64,6 +64,10 @@ OPTIONS
share no common history. This flag can be given to override that
check and make the merge proceed anyway.
+--merge-base=<commit>::
+ Instead of finding the merge-bases for <branch1> and <branch2>,
+ specify a merge-base for the merge.
+
[[OUTPUT]]
OUTPUT
------
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index ae5782917b9..adc461f00f3 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -3,6 +3,7 @@
#include "tree-walk.h"
#include "xdiff-interface.h"
#include "help.h"
+#include "commit.h"
#include "commit-reach.h"
#include "merge-ort.h"
#include "object-store.h"
@@ -402,6 +403,7 @@ struct merge_tree_options {
int allow_unrelated_histories;
int show_messages;
int name_only;
+ char* merge_base;
};
static int real_merge(struct merge_tree_options *o,
@@ -430,11 +432,18 @@ static int real_merge(struct merge_tree_options *o,
opt.branch1 = branch1;
opt.branch2 = branch2;
- /*
- * Get the merge bases, in reverse order; see comment above
- * merge_incore_recursive in merge-ort.h
- */
- merge_bases = get_merge_bases(parent1, parent2);
+ if (o->merge_base) {
+ struct commit *c = lookup_commit_reference_by_name(o->merge_base);
+ if (!c)
+ die(_("could not lookup commit %s"), o->merge_base);
+ commit_list_insert(c, &merge_bases);
+ } else {
+ /*
+ * Get the merge bases, in reverse order; see comment above
+ * merge_incore_recursive in merge-ort.h
+ */
+ merge_bases = get_merge_bases(parent1, parent2);
+ }
if (!merge_bases && !o->allow_unrelated_histories)
die(_("refusing to merge unrelated histories"));
merge_bases = reverse_commit_list(merge_bases);
@@ -505,6 +514,10 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
&o.allow_unrelated_histories,
N_("allow merging unrelated histories"),
PARSE_OPT_NONEG),
+ OPT_STRING(0, "merge-base",
+ &o.merge_base,
+ N_("commit"),
+ N_("specify a merge-base commit for the merge")),
OPT_END()
};
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 013b77144bd..032ff4a1c3d 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -819,4 +819,48 @@ test_expect_success SANITY 'merge-ort fails gracefully in a read-only repository
test_must_fail git -C read-only merge-tree side1 side2
'
+# specify merge-base as parent of branch2.
+# git merge-tree --merge-base=A O B
+# Commit O: foo, bar
+# Commit A: modify foo after Commit O
+# Commit B: modify bar after Commit A
+# Expected: foo is unchanged, modify bar
+
+test_expect_success 'specify merge-base as parent of branch2' '
+ # Setup
+ git init base-b2-p && (
+ cd base-b2-p &&
+ echo foo >foo &&
+ echo bar >bar &&
+ git add foo bar &&
+ git commit -m O &&
+
+ git branch O &&
+ git branch A &&
+
+ git checkout A &&
+ echo "A" >foo &&
+ git add foo &&
+ git commit -m A &&
+
+ git checkout -b B &&
+ echo "B" >bar &&
+ git add bar &&
+ git commit -m B
+ ) &&
+ # Testing
+ (
+ cd base-b2-p &&
+ TREE_OID=$(git merge-tree --merge-base=A O B) &&
+
+ q_to_tab <<-EOF >expect &&
+ 100644 blob $(git rev-parse B:bar)Qbar
+ 100644 blob $(git rev-parse O:foo)Qfoo
+ EOF
+
+ git ls-tree $TREE_OID >actual &&
+ test_cmp expect actual
+ )
+'
+
test_done
base-commit: db29e6bbaed156ae9025ff0474fd788e58230367
--
gitgitgadget
