cherry-pick: Suggest a better method to retain authorship

diff --git a/builtin-diff-index.c b/builtin-diff-index.c
index dc52c054ee680132ea2a5041d84c976cf036c773..083599d5c4c174cfab7c148428630534e4cd8174 100644 (file)
--- a/builtin-diff-index.c
+++ b/builtin-diff-index.c
@@ -9,13 +9,13 @@ static const char diff_cache_usage[] =
 "[<common diff options>] <tree-ish> [<path>...]"
 COMMON_DIFF_OPTIONS_HELP;
 
-int cmd_diff_index(int argc, const char **argv, char **envp)
+int cmd_diff_index(int argc, const char **argv, const char *prefix)
 {
        struct rev_info rev;
        int cached = 0;
        int i;
 
-       init_revisions(&rev);
+       init_revisions(&rev, prefix);
        git_config(git_default_config); /* no "diff" UI options */
        rev.abbrev = 0;
 
@@ -38,5 +38,9 @@ int cmd_diff_index(int argc, const char **argv, char **envp)
        if (rev.pending.nr != 1 ||
            rev.max_count != -1 || rev.min_age != -1 || rev.max_age != -1)
                usage(diff_cache_usage);
+       if (read_cache() < 0) {
+               perror("read_cache");
+               return -1;
+       }
        return run_diff_index(&rev, cached);
 }