[PATCH v4 2/2] merge-tree.c: support --merge-base in conjunction with --stdin

From

Kyle Zhao via GitGitGadget <gitgitgadget@gmail.com>

Date

Nov 1, 2022, 08:55 UTC

Message-ID

<db47fbc663eb0f3a1fc9a063dfb1051bc64601af.1667292904.git.gitgitgadget@gmail.com>

In-Reply-To

<pull.1397.v4.git.1667292904.gitgitgadget@gmail.com>

From: Kyle Zhao <kylezhao@tencent.com>

    printf "--merge-base=<b3> <b1> <b2>" | git merge-tree --stdin

This does a merge of b1 and b2, and uses b3 as the merge-base.

Signed-off-by: Kyle Zhao <kylezhao@tencent.com>
---
 Documentation/git-merge-tree.txt |  3 ++-
 builtin/merge-tree.c             | 22 ++++++++++++++++++++--
 t/t4301-merge-tree-write-tree.sh | 21 +++++++++++++++++++++
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-merge-tree.txt b/Documentation/git-merge-tree.txt
index d9dacb2ce54..be6a11bbaec 100644
--- a/Documentation/git-merge-tree.txt
+++ b/Documentation/git-merge-tree.txt
@@ -66,7 +66,8 @@ OPTIONS
 
 --merge-base=<commit>::
 	Instead of finding the merge-bases for <branch1> and <branch2>,
-	specify a merge-base for the merge.
+	specify a merge-base for the merge. When --stdin is passed, this
+	option should be passed into the input line.
 
 [[OUTPUT]]
 OUTPUT
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index f402b807c0f..7a8049e7b0c 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -551,16 +551,34 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
 
 		if (o.mode == MODE_TRIVIAL)
 			die(_("--trivial-merge is incompatible with all other options"));
+		if (merge_base)
+			die(_("--merge-base should be passed into the input line"));
 		line_termination = '\0';
 		while (strbuf_getline_lf(&buf, stdin) != EOF) {
 			struct strbuf **split;
 			int result;
+			const char *input_merge_base = NULL;
+			const char *arg;
 
 			split = strbuf_split(&buf, ' ');
-			if (!split[0] || !split[1] || split[2])
+			if (!split[0] || !split[1])
 				die(_("malformed input line: '%s'."), buf.buf);
 			strbuf_rtrim(split[0]);
-			result = real_merge(&o, merge_base, split[0]->buf, split[1]->buf, prefix);
+
+			/* parse --merge-base=<commit> option */
+			arg = split[0]->buf;
+			if (skip_prefix(arg, "--merge-base=", &arg))
+				input_merge_base = arg;
+
+			if (input_merge_base && split[2] && !split[3]) {
+				strbuf_rtrim(split[1]);
+				result = real_merge(&o, input_merge_base, split[1]->buf, split[2]->buf, prefix);
+			} else if (!input_merge_base && !split[2]) {
+				result = real_merge(&o, NULL, split[0]->buf, split[1]->buf, prefix);
+			} else {
+				die(_("malformed input line: '%s'."), buf.buf);
+			}
+
 			if (result < 0)
 				die(_("merging cannot continue; got unclean result of %d"), result);
 			strbuf_list_free(split);
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 5b0073d3dcd..aec2c00b91f 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -860,6 +860,13 @@ test_expect_success '--stdin with both a successful and a conflicted merge' '
 	test_cmp expect actual
 '
 
+
+test_expect_success '--merge-base is incompatible with --stdin' '
+	test_must_fail git merge-tree --merge-base=side1 --stdin 2>expect &&
+
+	grep "^fatal: --merge-base should be passed into the input line" expect
+'
+
 # specify merge-base as parent of branch2
 # git merge-tree --write-tree --merge-base=c2 c1 c3
 #   Commit c1: add file1
@@ -890,4 +897,18 @@ test_expect_success 'specify merge-base as parent of branch2' '
 	)
 '
 
+test_expect_success '--stdin with both a normal merge and a merge-base specified merge' '
+	cd base-b2-p &&
+	printf "c1 c3\n--merge-base=c2 c1 c3" | git merge-tree --stdin >actual &&
+
+	printf "1\0" >expect &&
+	git merge-tree --write-tree -z c1 c3 >>expect &&
+	printf "\0" >>expect &&
+
+	printf "1\0" >>expect &&
+	git merge-tree --write-tree -z --merge-base=c2 c1 c3 >>expect &&
+	printf "\0" >>expect &&
+	test_cmp expect actual
+'
+
 test_done

-- 
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