Subject: [PATCH] merge-recursive.c: Fix case-changing merge bug

From: David Turner <[email-masked]>
Date: Thu, 01 May 2014 20:21:09 -0400

On a case-insensitive filesystem, when merging, a file would be
wrongly deleted from the working tree if an incoming commit had
renamed it changing only its case.  When merging a rename, the file
with the old name would be deleted -- but since the filesystem
considers the old name to be the same as the new name, the new
file would in fact be deleted.

We avoid this by not deleting files that have a case-clone in the
index at stage 0.

Signed-off-by: David Turner <[email-masked]>
---
 merge-recursive.c           |  6 ++++++
 t/t7063-merge-ignorecase.sh | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100755 t/t7063-merge-ignorecase.sh

diff --git a/merge-recursive.c b/merge-recursive.c
index 4177092..cab16fa 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -589,6 +589,12 @@ static int remove_file(struct merge_options *o, int clean,
 			return -1;
 	}
 	if (update_working_directory) {
+		if (ignore_case) {
+			struct cache_entry *ce;
+			ce = cache_file_exists(path, strlen(path), ignore_case);
+			if (ce && ce_stage(ce) == 0)
+				return 0;
+		}
 		if (remove_path(path))
 			return -1;
 	}
diff --git a/t/t7063-merge-ignorecase.sh b/t/t7063-merge-ignorecase.sh
new file mode 100755
index 0000000..6d4959f
--- /dev/null
+++ b/t/t7063-merge-ignorecase.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+test_description='git-merge with case-changing rename on case-insensitive file system'
+
+. ./test-lib.sh
+
+if ! test_have_prereq CASE_INSENSITIVE_FS
+then
+	skip_all='skipping case insensitive tests - case sensitive file system'
+	test_done
+fi
+
+test_expect_success 'merge with case-changing rename with ignorecase=true' '
+	test $(git config core.ignorecase) = true &&
+	touch TestCase &&
+	git add TestCase &&
+	git commit -m "add TestCase" &&
+	git checkout -b with-camel &&
+	touch foo &&
+	git add foo &&
+	git commit -m "intervening commit" &&
+	git checkout master &&
+	git rm TestCase &&
+	touch testcase &&
+	git add testcase &&
+	git commit -m "rename to testcase" &&
+	git checkout with-camel &&
+	git merge master -m "merge" &&
+	test -e testcase
+'
+
+test_done
--