Merge branch 'nd/index-pack-error-message' into maint

* nd/index-pack-error-message:
index-pack: report error using the correct variable

diff --combined builtin/index-pack.c
index 2f37a38fbcdf131ab5897e47728c5773ba36b861,80c937413529153117e8e0fe0f205c5ef66de040..fa74972886cc8e6c0f6308e28de26a13cae6a2b7
--- 1/builtin/index-pack.c
--- 2/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@@ -1291,7 -1291,7 +1291,7 @@@ static void final(const char *final_pac
                if (keep_fd < 0) {
                        if (errno != EEXIST)
                                die_errno(_("cannot write keep file '%s'"),
-                                         keep_name);
+                                         keep_name ? keep_name : name);
                } else {
                        if (keep_msg_len > 0) {
                                write_or_die(keep_fd, keep_msg, keep_msg_len);
@@@ -1299,7 -1299,7 +1299,7 @@@
                        }
                        if (close(keep_fd) != 0)
                                die_errno(_("cannot close written keep file '%s'"),
-                                   keep_name);
+                                         keep_name ? keep_name : name);
                        report = "keep";
                }
        }
@@@ -1534,9 -1534,9 +1534,9 @@@ int cmd_index_pack(int argc, const cha
                                stat_only = 1;
                        } else if (!strcmp(arg, "--keep")) {
                                keep_msg = "";
 -                      } else if (!prefixcmp(arg, "--keep=")) {
 +                      } else if (starts_with(arg, "--keep=")) {
                                keep_msg = arg + 7;
 -                      } else if (!prefixcmp(arg, "--threads=")) {
 +                      } else if (starts_with(arg, "--threads=")) {
                                char *end;
                                nr_threads = strtoul(arg+10, &end, 0);
                                if (!arg[10] || *end || nr_threads < 0)
@@@ -1547,7 -1547,7 +1547,7 @@@
                                                  "ignoring %s"), arg);
                                nr_threads = 1;
  #endif
 -                      } else if (!prefixcmp(arg, "--pack_header=")) {
 +                      } else if (starts_with(arg, "--pack_header=")) {
                                struct pack_header *hdr;
                                char *c;
  
@@@ -1566,7 -1566,7 +1566,7 @@@
                                if (index_name || (i+1) >= argc)
                                        usage(index_pack_usage);
                                index_name = argv[++i];
 -                      } else if (!prefixcmp(arg, "--index-version=")) {
 +                      } else if (starts_with(arg, "--index-version=")) {
                                char *c;
                                opts.version = strtoul(arg + 16, &c, 10);
                                if (opts.version > 2)