Add check program "git-check-racy"

This will help counting the racily clean paths, but it should be
useless for daily use.  Do not even enable it in the makefile.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Makefile

@@ -194,7 +194,11 @@ PROGRAMS = \
 	git-update-server-info$X \
 	git-upload-pack$X git-verify-pack$X \
 	git-pack-redundant$X git-var$X \
-	git-describe$X git-merge-tree$X git-blame$X git-imap-send$X
+	git-describe$X git-merge-tree$X git-blame$X git-imap-send$X \
+	$(EXTRA_PROGRAMS)
+
+# Empty...
+EXTRA_PROGRAMS =
 
 BUILT_INS = \
 	git-format-patch$X git-show$X git-whatchanged$X \

check-racy.c

@@ -0,0 +1,28 @@
+#include "cache.h"
+
+int main(int ac, char **av)
+{
+	int i;
+	int dirty, clean, racy;
+
+	dirty = clean = racy = 0;
+	read_cache();
+	for (i = 0; i < active_nr; i++) {
+		struct cache_entry *ce = active_cache[i];
+		struct stat st;
+
+		if (lstat(ce->name, &st)) {
+			error("lstat(%s): %s", ce->name, strerror(errno));
+			continue;
+		}
+
+		if (ce_match_stat(ce, &st, 0))
+			dirty++;
+		else if (ce_match_stat(ce, &st, 2))
+			racy++;
+		else
+			clean++;
+	}
+	printf("dirty %d, clean %d, racy %d\n", dirty, clean, racy);
+	return 0;
+}

read-cache.c

@@ -169,9 +169,11 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 	return changed;
 }
 
-int ce_match_stat(struct cache_entry *ce, struct stat *st, int ignore_valid)
+int ce_match_stat(struct cache_entry *ce, struct stat *st, int options)
 {
 	unsigned int changed;
+	int ignore_valid = options & 01;
+	int assume_racy_is_modified = options & 02;
 
 	/*
 	 * If it's marked as always valid in the index, it's
@@ -200,8 +202,12 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st, int ignore_valid)
 	 */
 	if (!changed &&
 	    index_file_timestamp &&
-	    index_file_timestamp <= ntohl(ce->ce_mtime.sec))
-		changed |= ce_modified_check_fs(ce, st);
+	    index_file_timestamp <= ntohl(ce->ce_mtime.sec)) {
+		if (assume_racy_is_modified)
+			changed |= DATA_CHANGED;
+		else
+			changed |= ce_modified_check_fs(ce, st);
+	}
 
 	return changed;
 }