[PATCH v1] name-hash: properly fold directory names in adjust_dirname_case()

[Ben Peart]

Correct the pointer arithmetic in adjust_dirname_case() so that it calls
find_dir_entry() with the correct string length.  Previously passing in
"dir1/foo" would pass a length of 6 instead of the correct 4.  This resulted in
find_dir_entry() never finding the entry and so the subsequent memcpy that would
fold the name to the version with the correct case never executed.

Add a test to validate the corrected behavior with name folding of directories.

Signed-off-by: Ben Peart <benpe...@microsoft.com>
---

Notes:
    Base Ref: v2.16.1
    Web-Diff: https://github.com/benpeart/git/commit/2944970f4e
    Checkout: git fetch https://github.com/benpeart/git adjust_dirname-v1 && 
git checkout 2944970f4e

 name-hash.c           |  6 +++---
 t/t0050-filesystem.sh | 12 +++++++++++-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/name-hash.c b/name-hash.c
index 45c98db0a0..2ddbb72647 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -696,12 +696,12 @@ void adjust_dirname_case(struct index_state *istate, char 
*name)
                if (*ptr == '/') {
                        struct dir_entry *dir;
 
-                       ptr++;
-                       dir = find_dir_entry(istate, name, ptr - name + 1);
+                       dir = find_dir_entry(istate, name, ptr - name);
                        if (dir) {
                                memcpy((void *)startPtr, dir->name + (startPtr 
- name), ptr - startPtr);
-                               startPtr = ptr;
+                               startPtr = ptr + 1;
                        }
+                       ptr++;
                }
        }
 }
diff --git a/t/t0050-filesystem.sh b/t/t0050-filesystem.sh
index b29d749bb7..219c96594c 100755
--- a/t/t0050-filesystem.sh
+++ b/t/t0050-filesystem.sh
@@ -80,7 +80,17 @@ test_expect_success 'merge (case change)' '
        git merge topic
 '
 
-
+test_expect_success CASE_INSENSITIVE_FS 'add directory (with different case)' '
+       git reset --hard initial &&
+       mkdir -p dir1 &&
+       mkdir -p dir1/dir2 &&
+       touch dir1/dir2/a &&
+       touch dir1/dir2/b &&
+       git add dir1/dir2/a &&
+       git add dir1/DIR2/b &&
+       camel=$(git ls-files | grep dir2) &&
+       test $(echo "$camel" | wc -l) = 2
+'
 
 test_expect_failure CASE_INSENSITIVE_FS 'add (with different case)' '
        git reset --hard initial &&

base-commit: 8279ed033f703d4115bee620dccd32a9ec94d9aa
-- 
2.15.0.windows.1