[PATCH 1/3] merge-recursive.c: conflict using sparse should update file

[Kevin Willford <kcwillford@gmail.com>]

Update the file when there is a conflict with a modify/delete scenario
when using the sparse-checkout feature since the file might not be on disk
because the skip-worktree bit is on and the user will need the file and
content to determine how to resolve the conflict.

Signed-off-by: Kevin Willford <kewillf@microsoft.com>
---
 merge-recursive.c                |  8 ++++++++
 t/t7614-merge-sparse-checkout.sh | 27 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100755 t/t7614-merge-sparse-checkout.sh

diff --git a/merge-recursive.c b/merge-recursive.c
index b7ff1ada3c..54fce93dae 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1103,6 +1103,14 @@ static int handle_change_delete(struct merge_options *o,
 			       "and %s in %s. Version %s of %s left in tree."),
 			       change, path, o->branch2, change_past,
 			       o->branch1, o->branch1, path);
+			/*
+			 * In a sparse checkout the file may not exist. Sadly,
+			 * the CE_SKIP_WORKTREE flag is not preserved in the
+			 * case of conflicts, therefore we do the next best
+			 * thing: verify that the file exists.
+			 */
+			if (!file_exists(path))
+				ret = update_file(o, 0, a_oid, a_mode, path);
 		} else {
 			output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 			       "and %s in %s. Version %s of %s left in tree at %s."),
diff --git a/t/t7614-merge-sparse-checkout.sh b/t/t7614-merge-sparse-checkout.sh
new file mode 100755
index 0000000000..6922f0244f
--- /dev/null
+++ b/t/t7614-merge-sparse-checkout.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+
+test_description='merge can handle sparse-checkout'
+
+. ./test-lib.sh
+
+# merges with conflicts
+
+test_expect_success 'setup' '
+	test_commit a &&
+	test_commit file &&
+	git checkout -b delete-file &&
+	git rm file.t &&
+	test_tick &&
+	git commit -m "remove file" &&
+	git checkout master &&
+	test_commit modify file.t changed
+'
+
+test_expect_success 'merge conflict deleted file and modified' '
+	echo "/a" >.git/info/sparse-checkout &&
+	test_config core.sparsecheckout true &&
+	test_must_fail git merge delete-file &&
+	test_path_is_file file.t
+'
+
+test_done
-- 
2.12.2.windows.2.1.g7df5db8d31