[PATCH v4 0/1] subtree: validate --prefix against commit in split

Pushkar Singh· Jan 23, 2026, 14:26 UTC · lore

Changes in v4:
 * fix indentation in the case statement
 * add a regression test to ensure --prefix is validated against the
   target commit rather than the working tree

No functional changes beyond the above.

Pushkar Singh (1):
  subtree: validate --prefix against commit in split

 contrib/subtree/git-subtree.sh     |  9 +++++++++
 contrib/subtree/t/t7900-subtree.sh | 22 ++++++++++++++++++++++
 2 files changed, 31 insertions(+)

-- 
2.43.0

Pushkar Singh· Jan 23, 2026, 14:35 UTC · re: Pushkar Singh · lore

[PATCH v4 1/1] subtree: validate --prefix against commit in split

git subtree split currently validates --prefix against the working tree. This breaks when splitting an older commit or when the working tree does not contain the subtree, even though the commit does.

For example:

  git subtree split --prefix=pkg <commit>

fails if pkg was removed later, even though it exists in <commit>.

Fix this by validating the prefix against the specified commit using git ls-tree instead of the working tree.

Add a test to ensure this behavior does not regress.

Address review feedback by fixing indentation and adding regression test.

Signed-off-by: Pushkar Singh <pushkarkumarsingh1970@gmail.com>
---
 contrib/subtree/git-subtree.sh     |  9 +++++++++
 contrib/subtree/t/t7900-subtree.sh | 22 ++++++++++++++++++++++
 2 files changed, 31 insertions(+)

Show changes to 2 files +31 −0

contrib/subtree/git-subtree.sh, contrib/subtree/t/t7900-subtree.sh

diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index 17106d1a72..324ed38148 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -257,6 +257,9 @@ main () {
 		test -e "$arg_prefix" &&
 			die "fatal: prefix '$arg_prefix' already exists."
 		;;
+	split)
+		# checked later against the commit, not the working tree
+		;;
 	*)
 		test -e "$arg_prefix" ||
 			die "fatal: '$arg_prefix' does not exist; use 'git subtree add'"
@@ -966,6 +969,12 @@ cmd_split () {
 	else
 		die "fatal: you must provide exactly one revision, and optionally a repository.  Got: '$*'"
 	fi
+
+	# Now validate prefix against the commit, not the working tree
+	if ! git ls-tree -d "$rev" -- "$dir" >/dev/null
+	then
+		die "fatal: '$dir' does not exist in commit $rev"
+	fi
 	repository=""
 	if test "$#" = 2
 	then
diff --git a/contrib/subtree/t/t7900-subtree.sh b/contrib/subtree/t/t7900-subtree.sh
index 316dc5269e..e4f632f3af 100755
--- a/contrib/subtree/t/t7900-subtree.sh
+++ b/contrib/subtree/t/t7900-subtree.sh
@@ -368,6 +368,28 @@ test_expect_success 'split requires path given by option --prefix must exist' '
 	)
 '
 
+test_expect_success 'split works when prefix exists in commit but not in working tree' '
+	subtree_test_create_repo "$test_count" &&
+	(
+		cd "$test_count" &&
+
+		# create subtree
+		mkdir pkg &&
+		echo ok >pkg/file &&
+		git add pkg &&
+		git commit -m "add pkg" &&
+		good=$(git rev-parse HEAD) &&
+
+		# remove it from working tree in later commit
+		git rm -r pkg &&
+		git commit -m "remove pkg" &&
+
+		# must still be able to split using the old commit
+		git subtree split --prefix=pkg "$good" >out &&
+		test -s out
+	)
+'
+
 test_expect_success 'split rejects flags for add' '
 	subtree_test_create_repo "$test_count" &&
 	subtree_test_create_repo "$test_count/sub proj" &&

-- 
2.43.0

Junio C Hamano· Jan 23, 2026, 17:37 UTC · re: Pushkar Singh · lore

Re: [PATCH v4 0/1] subtree: validate --prefix against commit in split

Pushkar Singh <pushkarkumarsingh1970@gmail.com> writes:

Show 6 quoted lines

> Changes in v4:
>  * fix indentation in the case statement
>  * add a regression test to ensure --prefix is validated against the
>    target commit rather than the working tree
>
> No functional changes beyond the above.

This seems to be identical to v3, which already had the fix to the case and addition of tests.

https://lore.kernel.org/git/20260115175403.3971-3-pushkarkumarsingh1970@gmail.com/

v4subtree: validate --prefix against commit in split