log_ref_setup(): improve robustness against races

diff --git a/diff.c b/diff.c
index ec8728362dae5a3bf404f6782f9091d6a1c9a6c2..84dba60c405b588ed794a2539ce3cddaa1fbaf8b 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -3106,7 +3106,8 @@ static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
                        abbrev = FALLBACK_DEFAULT_ABBREV;
                if (abbrev > GIT_SHA1_HEXSZ)
                        die("BUG: oid abbreviation out of range: %d", abbrev);
-               hex[abbrev] = '\0';
+               if (abbrev)
+                       hex[abbrev] = '\0';
                return hex;
        }
 }
@@ -3364,6 +3365,7 @@ void diff_setup(struct diff_options *options)
 
        options->file = stdout;
 
+       options->abbrev = DEFAULT_ABBREV;
        options->line_termination = '\n';
        options->break_opt = -1;
        options->rename_limit = -1;
@@ -4024,6 +4026,8 @@ int diff_opt_parse(struct diff_options *options,
                            offending, optarg);
                return argcount;
        }
+       else if (!strcmp(arg, "--no-abbrev"))
+               options->abbrev = 0;
        else if (!strcmp(arg, "--abbrev"))
                options->abbrev = DEFAULT_ABBREV;
        else if (skip_prefix(arg, "--abbrev=", &arg)) {