diff-lib: fix check_removed when fsmonitor is on

`git diff-index` may return incorrect deleted entries when fsmonitor
is used in a repository with git submodules. This can be observed on
Mac machines, but it can affect all other supported platforms too.

If fsmonitor is used, `stat *st` is not initialized if cache_entry has
CE_FSMONITOR_VALID set. But, there are three call sites that rely on stat
afterwards, which can result in incorrect results.

This change partially reverts commit 4f3d6d02 (fsmonitor: skip lstat
deletion check during git diff-index, 2021-03-17).

Signed-off-by: Josip Sokcevic <sokcevic@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff-lib.c b/diff-lib.c
index 2edea41a2345af623017d43e14a74d71a32bb873..083e18dc9d071a3ab26b1a4a3ad67bb6d7438dcb 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -28,14 +28,14 @@
  * exists for ce that is a submodule -- it is a submodule that is not
  * checked out).  Return negative for an error.
  */
-static int check_removed(const struct index_state *istate, const struct cache_entry *ce, struct stat *st)
+static int check_removed(const struct cache_entry *ce, struct stat *st)
 {
-       assert(is_fsmonitor_refreshed(istate));
-       if (!(ce->ce_flags & CE_FSMONITOR_VALID) && lstat(ce->name, st) < 0) {
+       if (lstat(ce->name, st) < 0) {
                if (!is_missing_file_error(errno))
                        return -1;
                return 1;
        }
+
        if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
                return 1;
        if (S_ISDIR(st->st_mode)) {
@@ -141,7 +141,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
                        memset(&(dpath->parent[0]), 0,
                               sizeof(struct combine_diff_parent)*5);
 
-                       changed = check_removed(istate, ce, &st);
+                       changed = check_removed(ce, &st);
                        if (!changed)
                                wt_mode = ce_mode_from_stat(ce, st.st_mode);
                        else {
@@ -221,7 +221,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
                } else {
                        struct stat st;
 
-                       changed = check_removed(istate, ce, &st);
+                       changed = check_removed(ce, &st);
                        if (changed) {
                                if (changed < 0) {
                                        perror(ce->name);
@@ -296,7 +296,7 @@ static int get_stat_data(const struct index_state *istate,
        if (!cached && !ce_uptodate(ce)) {
                int changed;
                struct stat st;
-               changed = check_removed(istate, ce, &st);
+               changed = check_removed(ce, &st);
                if (changed < 0)
                        return -1;
                else if (changed) {

diff --git a/t/t7527-builtin-fsmonitor.sh b/t/t7527-builtin-fsmonitor.sh
index d419085379ce6c38fce7baf68160ce0faf2898be..1d4c0cbab8afa5bdd16a60ad6cd5357210a31279 100755 (executable)
--- a/t/t7527-builtin-fsmonitor.sh
+++ b/t/t7527-builtin-fsmonitor.sh
@@ -809,6 +809,11 @@ my_match_and_clean () {
                status --porcelain=v2 >actual.without &&
        test_cmp actual.with actual.without &&
 
+       git -C super --no-optional-locks diff-index --name-status HEAD >actual.with &&
+       git -C super --no-optional-locks -c core.fsmonitor=false \
+               diff-index --name-status HEAD >actual.without &&
+       test_cmp actual.with actual.without &&
+
        git -C super/dir_1/dir_2/sub reset --hard &&
        git -C super/dir_1/dir_2/sub clean -d -f
 }