Merge branch 'rs/pax-extended-header-length-fix'

"git archive" recorded incorrect length in extended pax header in
some corner cases, which has been corrected.

* rs/pax-extended-header-length-fix:
archive-tar: turn length miscalculation warning into BUG
archive-tar: use size_t in strbuf_append_ext_header()
archive-tar: fix pax extended header length calculation
archive-tar: report wrong pax extended header length

diff --combined archive-tar.c
index 3e53aac1e6523571ce0b9cb02d151c1f00652603,e7153c69e7a87322afa8a8614bf6c5796da5a701..e16d3f756ddd61d38477e73b71aa01e912ba2b13
--- 1/archive-tar.c
--- 2/archive-tar.c
+++ b/archive-tar.c
@@@ -142,19 -142,25 +142,25 @@@ static int stream_blocked(const struct 
   * string and appends it to a struct strbuf.
   */
  static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
-                                    const char *value, unsigned int valuelen)
+                                    const char *value, size_t valuelen)
  {
-       int len, tmp;
+       size_t orig_len = sb->len;
+       size_t len, tmp;
  
        /* "%u %s=%s\n" */
        len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
-       for (tmp = len; tmp > 9; tmp /= 10)
+       for (tmp = 1; len / 10 >= tmp; tmp *= 10)
                len++;
  
        strbuf_grow(sb, len);
-       strbuf_addf(sb, "%u %s=", len, keyword);
+       strbuf_addf(sb, "%"PRIuMAX" %s=", (uintmax_t)len, keyword);
        strbuf_add(sb, value, valuelen);
        strbuf_addch(sb, '\n');
+ 
+       if (len != sb->len - orig_len)
+               BUG("pax extended header length miscalculated as %"PRIuMAX
+                   ", should be %"PRIuMAX,
+                   (uintmax_t)len, (uintmax_t)(sb->len - orig_len));
  }
  
  /*
@@@ -326,15 -332,14 +332,15 @@@ static int write_tar_entry(struct archi
  
  static void write_global_extended_header(struct archiver_args *args)
  {
 -      const unsigned char *sha1 = args->commit_sha1;
 +      const struct object_id *oid = args->commit_oid;
        struct strbuf ext_header = STRBUF_INIT;
        struct ustar_header header;
        unsigned int mode;
  
 -      if (sha1)
 +      if (oid)
                strbuf_append_ext_header(&ext_header, "comment",
 -                                       sha1_to_hex(sha1), 40);
 +                                       oid_to_hex(oid),
 +                                       the_hash_algo->hexsz);
        if (args->time > USTAR_MAX_MTIME) {
                strbuf_append_ext_header_uint(&ext_header, "mtime",
                                              args->time);