commit 35d2583f834a66f801dc229002d45e735882ba78
from: Stefan Sperling <stsp@stsp.name>
date: Mon Apr 17 15:53:19 2023 UTC

allow no-op merge commits to be created

Requested by James Cook

commit - 2b70695630ead3274d31727f6b477f3544dc9c9a
commit + 35d2583f834a66f801dc229002d45e735882ba78
blob - c924075eacdb3d7e5ebe3fc11b3c59262e7e120f
blob + 923e489c4fb37899470241b32f5235c9b6652c87
--- got/got.1
+++ got/got.1
@@ -2851,10 +2851,6 @@ The work tree may be modified as desired and the merge
 once the changes present in the work tree are considered complete.
 Alternatively, the merge operation may be aborted which will leave
 the work tree's current branch unmodified.
-.Pp
-If a merge conflict is resolved in a way which renders all merged
-changes into no-op changes, the merge operation cannot continue
-and must be aborted.
 .Pp
 .Cm got merge
 will refuse to run if certain preconditions are not met.
blob - 2bc8caf5426fa97b5db0fe63e371b0cbd9347786
blob + 622c0ce1ca669ed14ca0d26259483e9beea95863
--- lib/worktree.c
+++ lib/worktree.c
@@ -8388,13 +8388,7 @@ got_worktree_merge_commit(struct got_object_id **new_c
 	err = worktree_status(worktree, "", fileindex, repo,
 	    collect_commitables, &cc_arg, NULL, NULL, 1, 0);
 	if (err)
-		goto done;
-
-	if (TAILQ_EMPTY(&commitable_paths)) {
-		err = got_error_fmt(GOT_ERR_COMMIT_NO_CHANGES,
-		    "merge of %s cannot proceed", branch_name);
 		goto done;
-	}
 
 	TAILQ_FOREACH(pe, &commitable_paths, entry) {
 		struct got_commitable *ct = pe->data;
blob - 9093dd5b9fb524b14d2d17d4fe754da0ec8ef9f4
blob + 11ffa61f4a12efd380087a03aa5b186b9a745ae2
--- regress/cmdline/merge.sh
+++ regress/cmdline/merge.sh
@@ -1045,7 +1045,7 @@ test_merge_no_op() {
 	(cd $testroot/repo && git checkout -q -b newbranch)
 	echo "modified alpha on branch" > $testroot/repo/alpha
 	git_commit $testroot/repo -m "committing to alpha on newbranch"
-	local branch_commitk=`git_show_branch_head $testroot/repo newbranch`
+	local branch_commit=`git_show_branch_head $testroot/repo newbranch`
 
 	got checkout -b master $testroot/repo $testroot/wt > /dev/null
 	ret=$?
@@ -1122,19 +1122,30 @@ test_merge_no_op() {
 	(cd $testroot/wt && got merge -c > $testroot/stdout \
 		2> $testroot/stderr)
 	ret=$?
-	if [ $ret -eq 0 ]; then
-		echo "got merge succeeded unexpectedly" >&2
+	if [ $ret -ne 0 ]; then
+		echo "got merge failed unexpectedly" >&2
 		test_done "$testroot" "$ret"
 		return 1
 	fi
 
-	echo -n "got: merge of refs/heads/newbranch cannot proceed: " \
-		> $testroot/stderr.expected
-	echo "no changes to commit" >> $testroot/stderr.expected
+	echo -n '' > $testroot/stderr.expected
 	cmp -s $testroot/stderr.expected $testroot/stderr
 	ret=$?
 	if [ $ret -ne 0 ]; then
 		diff -u $testroot/stderr.expected $testroot/stderr
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	local merge_commit=`git_show_head $testroot/repo`
+	echo -n "Merged refs/heads/newbranch into refs/heads/master: " \
+		> $testroot/stdout.expected
+	echo $merge_commit >> $testroot/stdout.expected
+
+	cmp -s $testroot/stdout.expected $testroot/stdout
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/stdout.expected $testroot/stdout
 		test_done "$testroot" "$ret"
 		return 1
 	fi
@@ -1146,7 +1157,20 @@ test_merge_no_op() {
 	ret=$?
 	if [ $ret -ne 0 ]; then
 		diff -u $testroot/stdout.expected $testroot/stdout
+		test_done "$testroot" "$ret"
+		return 1
 	fi
+
+	# We should have created a merge commit with two parents.
+	got log -r $testroot/repo -l1 -c $merge_commit | grep ^parent \
+		> $testroot/stdout
+	echo "parent 1: $master_commit" > $testroot/stdout.expected
+	echo "parent 2: $branch_commit" >> $testroot/stdout.expected
+	cmp -s $testroot/stdout.expected $testroot/stdout
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/stdout.expected $testroot/stdout
+	fi
 	test_done "$testroot" "$ret"
 }