Merge branch 'lt/fix-sol-pack' into next
authorJunio C Hamano <junkio@cox.net>
Tue, 4 Apr 2006 06:43:16 +0000 (23:43 -0700)
committerJunio C Hamano <junkio@cox.net>
Tue, 4 Apr 2006 06:43:16 +0000 (23:43 -0700)
* lt/fix-sol-pack:
  Use sigaction and SA_RESTART in read-tree.c; add option in Makefile.
  safe_fgets() - even more anal fgets()

1  2 
pack-objects.c
read-tree.c

diff --combined pack-objects.c
@@@ -3,7 -3,6 +3,7 @@@
  #include "delta.h"
  #include "pack.h"
  #include "csum-file.h"
 +#include "tree-walk.h"
  #include <sys/time.h>
  #include <signal.h>
  
@@@ -28,10 -27,6 +28,10 @@@ struct object_entry 
        struct object_entry *delta_sibling; /* other deltified objects who
                                             * uses the same base as me
                                             */
 +      int preferred_base;     /* we do not pack this, but is encouraged to
 +                               * be used as the base objectto delta huge
 +                               * objects against.
 +                               */
  };
  
  /*
@@@ -54,7 -49,7 +54,7 @@@ static int local = 0
  static int incremental = 0;
  static struct object_entry **sorted_by_sha, **sorted_by_type;
  static struct object_entry *objects = NULL;
 -static int nr_objects = 0, nr_alloc = 0;
 +static int nr_objects = 0, nr_alloc = 0, nr_result = 0;
  static const char *base_name;
  static unsigned char pack_file_sha1[20];
  static int progress = 1;
@@@ -96,7 -91,7 +96,7 @@@ static int reused_delta = 0
  
  static int pack_revindex_ix(struct packed_git *p)
  {
 -      unsigned int ui = (unsigned int) p;
 +      unsigned long ui = (unsigned long)p;
        int i;
  
        ui = ui ^ (ui >> 16); /* defeat structure alignment */
@@@ -236,8 -231,7 +236,8 @@@ static int encode_header(enum object_ty
        return n;
  }
  
 -static unsigned long write_object(struct sha1file *f, struct object_entry *entry)
 +static unsigned long write_object(struct sha1file *f,
 +                                struct object_entry *entry)
  {
        unsigned long size;
        char type[10];
        enum object_type obj_type;
        int to_reuse = 0;
  
 +      if (entry->preferred_base)
 +              return 0;
 +
        obj_type = entry->type;
        if (! entry->in_pack)
                to_reuse = 0;   /* can't reuse what we don't have */
@@@ -344,22 -335,20 +344,22 @@@ static void write_pack_file(void
                do_progress = progress;
        }
        if (do_progress)
 -              fprintf(stderr, "Writing %d objects.\n", nr_objects);
 +              fprintf(stderr, "Writing %d objects.\n", nr_result);
  
        hdr.hdr_signature = htonl(PACK_SIGNATURE);
        hdr.hdr_version = htonl(PACK_VERSION);
 -      hdr.hdr_entries = htonl(nr_objects);
 +      hdr.hdr_entries = htonl(nr_result);
        sha1write(f, &hdr, sizeof(hdr));
        offset = sizeof(hdr);
 +      if (!nr_result)
 +              goto done;
        for (i = 0; i < nr_objects; i++) {
                offset = write_one(f, objects + i, offset);
                if (do_progress) {
 -                      unsigned percent = written * 100 / nr_objects;
 +                      unsigned percent = written * 100 / nr_result;
                        if (progress_update || percent != last_percent) {
                                fprintf(stderr, "%4u%% (%u/%u) done\r",
 -                                      percent, written, nr_objects);
 +                                      percent, written, nr_result);
                                progress_update = 0;
                                last_percent = percent;
                        }
        }
        if (do_progress)
                fputc('\n', stderr);
 -
 + done:
        sha1close(f, pack_file_sha1, 1);
  }
  
  static void write_index_file(void)
  {
        int i;
 -      struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx");
 +      struct sha1file *f = sha1create("%s-%s.%s", base_name,
 +                                      sha1_to_hex(object_list_sha1), "idx");
        struct object_entry **list = sorted_by_sha;
 -      struct object_entry **last = list + nr_objects;
 +      struct object_entry **last = list + nr_result;
        unsigned int array[256];
  
        /*
         * Write the actual SHA1 entries..
         */
        list = sorted_by_sha;
 -      for (i = 0; i < nr_objects; i++) {
 +      for (i = 0; i < nr_result; i++) {
                struct object_entry *entry = *list++;
                unsigned int offset = htonl(entry->offset);
                sha1write(f, &offset, 4);
        sha1close(f, NULL, 1);
  }
  
 -static int add_object_entry(unsigned char *sha1, unsigned int hash)
 +static int locate_object_entry_hash(const unsigned char *sha1)
 +{
 +      int i;
 +      unsigned int ui;
 +      memcpy(&ui, sha1, sizeof(unsigned int));
 +      i = ui % object_ix_hashsz;
 +      while (0 < object_ix[i]) {
 +              if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
 +                      return i;
 +              if (++i == object_ix_hashsz)
 +                      i = 0;
 +      }
 +      return -1 - i;
 +}
 +
 +static struct object_entry *locate_object_entry(const unsigned char *sha1)
 +{
 +      int i;
 +
 +      if (!object_ix_hashsz)
 +              return NULL;
 +
 +      i = locate_object_entry_hash(sha1);
 +      if (0 <= i)
 +              return &objects[object_ix[i]-1];
 +      return NULL;
 +}
 +
 +static void rehash_objects(void)
 +{
 +      int i;
 +      struct object_entry *oe;
 +
 +      object_ix_hashsz = nr_objects * 3;
 +      if (object_ix_hashsz < 1024)
 +              object_ix_hashsz = 1024;
 +      object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 +      object_ix = memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 +      for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 +              int ix = locate_object_entry_hash(oe->sha1);
 +              if (0 <= ix)
 +                      continue;
 +              ix = -1 - ix;
 +              object_ix[ix] = i + 1;
 +      }
 +}
 +
 +struct name_path {
 +      struct name_path *up;
 +      const char *elem;
 +      int len;
 +};
 +
 +#define DIRBITS 12
 +
 +static unsigned name_hash(struct name_path *path, const char *name)
 +{
 +      struct name_path *p = path;
 +      const char *n = name + strlen(name);
 +      unsigned hash = 0, name_hash = 0, name_done = 0;
 +
 +      if (n != name && n[-1] == '\n')
 +              n--;
 +      while (name <= --n) {
 +              unsigned char c = *n;
 +              if (c == '/' && !name_done) {
 +                      name_hash = hash;
 +                      name_done = 1;
 +                      hash = 0;
 +              }
 +              hash = hash * 11 + c;
 +      }
 +      if (!name_done) {
 +              name_hash = hash;
 +              hash = 0;
 +      }
 +      for (p = path; p; p = p->up) {
 +              hash = hash * 11 + '/';
 +              n = p->elem + p->len;
 +              while (p->elem <= --n) {
 +                      unsigned char c = *n;
 +                      hash = hash * 11 + c;
 +              }
 +      }
 +      /*
 +       * Make sure "Makefile" and "t/Makefile" are hashed separately
 +       * but close enough.
 +       */
 +      hash = (name_hash<<DIRBITS) | (hash & ((1U<<DIRBITS )-1));
 +
 +      if (0) { /* debug */
 +              n = name + strlen(name);
 +              if (n != name && n[-1] == '\n')
 +                      n--;
 +              while (name <= --n)
 +                      fputc(*n, stderr);
 +              for (p = path; p; p = p->up) {
 +                      fputc('/', stderr);
 +                      n = p->elem + p->len;
 +                      while (p->elem <= --n)
 +                              fputc(*n, stderr);
 +              }
 +              fprintf(stderr, "\t%08x\n", hash);
 +      }
 +      return hash;
 +}
 +
 +static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
  {
        unsigned int idx = nr_objects;
        struct object_entry *entry;
        struct packed_git *p;
        unsigned int found_offset = 0;
        struct packed_git *found_pack = NULL;
 -
 -      for (p = packed_git; p; p = p->next) {
 -              struct pack_entry e;
 -              if (find_pack_entry_one(sha1, &e, p)) {
 -                      if (incremental)
 -                              return 0;
 -                      if (local && !p->pack_local)
 -                              return 0;
 -                      if (!found_pack) {
 -                              found_offset = e.offset;
 -                              found_pack = e.p;
 +      int ix, status = 0;
 +
 +      if (!exclude) {
 +              for (p = packed_git; p; p = p->next) {
 +                      struct pack_entry e;
 +                      if (find_pack_entry_one(sha1, &e, p)) {
 +                              if (incremental)
 +                                      return 0;
 +                              if (local && !p->pack_local)
 +                                      return 0;
 +                              if (!found_pack) {
 +                                      found_offset = e.offset;
 +                                      found_pack = e.p;
 +                              }
                        }
                }
        }
 +      if ((entry = locate_object_entry(sha1)) != NULL)
 +              goto already_added;
  
        if (idx >= nr_alloc) {
                unsigned int needed = (idx + 1024) * 3 / 2;
                nr_alloc = needed;
        }
        entry = objects + idx;
 +      nr_objects = idx + 1;
        memset(entry, 0, sizeof(*entry));
        memcpy(entry->sha1, sha1, 20);
        entry->hash = hash;
 -      if (found_pack) {
 -              entry->in_pack = found_pack;
 -              entry->in_pack_offset = found_offset;
 +
 +      if (object_ix_hashsz * 3 <= nr_objects * 4)
 +              rehash_objects();
 +      else {
 +              ix = locate_object_entry_hash(entry->sha1);
 +              if (0 <= ix)
 +                      die("internal error in object hashing.");
 +              object_ix[-1 - ix] = idx + 1;
        }
 -      nr_objects = idx+1;
 -      return 1;
 +      status = 1;
 +
 + already_added:
 +      if (progress_update) {
 +              fprintf(stderr, "Counting objects...%d\r", nr_objects);
 +              progress_update = 0;
 +      }
 +      if (exclude)
 +              entry->preferred_base = 1;
 +      else {
 +              if (found_pack) {
 +                      entry->in_pack = found_pack;
 +                      entry->in_pack_offset = found_offset;
 +              }
 +      }
 +      return status;
  }
  
 -static int locate_object_entry_hash(unsigned char *sha1)
 +static void add_pbase_tree(struct tree_desc *tree, struct name_path *up)
  {
 -      int i;
 -      unsigned int ui;
 -      memcpy(&ui, sha1, sizeof(unsigned int));
 -      i = ui % object_ix_hashsz;
 -      while (0 < object_ix[i]) {
 -              if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
 -                      return i;
 -              if (++i == object_ix_hashsz)
 -                      i = 0;
 +      while (tree->size) {
 +              const unsigned char *sha1;
 +              const char *name;
 +              unsigned mode, hash;
 +              unsigned long size;
 +              char type[20];
 +
 +              sha1 = tree_entry_extract(tree, &name, &mode);
 +              update_tree_entry(tree);
 +              if (!has_sha1_file(sha1))
 +                      continue;
 +              if (sha1_object_info(sha1, type, &size))
 +                      continue;
 +
 +              hash = name_hash(up, name);
 +              if (!add_object_entry(sha1, hash, 1))
 +                      continue;
 +
 +              if (!strcmp(type, "tree")) {
 +                      struct tree_desc sub;
 +                      void *elem;
 +                      struct name_path me;
 +
 +                      elem = read_sha1_file(sha1, type, &sub.size);
 +                      sub.buf = elem;
 +                      if (sub.buf) {
 +                              me.up = up;
 +                              me.elem = name;
 +                              me.len = strlen(name);
 +                              add_pbase_tree(&sub, &me);
 +                              free(elem);
 +                      }
 +              }
        }
 -      return -1 - i;
  }
  
 -static struct object_entry *locate_object_entry(unsigned char *sha1)
 +static void add_preferred_base(unsigned char *sha1)
  {
 -      int i = locate_object_entry_hash(sha1);
 -      if (0 <= i)
 -              return &objects[object_ix[i]-1];
 -      return NULL;
 +      struct tree_desc tree;
 +      void *elem;
 +
 +      elem = read_object_with_reference(sha1, "tree", &tree.size, NULL);
 +      tree.buf = elem;
 +      if (!tree.buf)
 +              return;
 +      if (add_object_entry(sha1, name_hash(NULL, ""), 1))
 +              add_pbase_tree(&tree, NULL);
 +      free(elem);
  }
  
  static void check_object(struct object_entry *entry)
  {
        char type[20];
  
 -      if (entry->in_pack) {
 +      if (entry->in_pack && !entry->preferred_base) {
                unsigned char base[20];
                unsigned long size;
                struct object_entry *base_entry;
                 */
                if (!no_reuse_delta &&
                    entry->in_pack_type == OBJ_DELTA &&
 -                  (base_entry = locate_object_entry(base))) {
 +                  (base_entry = locate_object_entry(base)) &&
 +                  (!base_entry->preferred_base)) {
  
                        /* Depth value does not matter - find_deltas()
                         * will never consider reused delta as the
                    sha1_to_hex(entry->sha1), type);
  }
  
 -static void hash_objects(void)
 -{
 -      int i;
 -      struct object_entry *oe;
 -
 -      object_ix_hashsz = nr_objects * 2;
 -      object_ix = xcalloc(sizeof(int), object_ix_hashsz);
 -      for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 -              int ix = locate_object_entry_hash(oe->sha1);
 -              if (0 <= ix) {
 -                      error("the same object '%s' added twice",
 -                            sha1_to_hex(oe->sha1));
 -                      continue;
 -              }
 -              ix = -1 - ix;
 -              object_ix[ix] = i + 1;
 -      }
 -}
 -
  static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
  {
        struct object_entry *child = me->delta_child;
@@@ -715,26 -560,14 +715,26 @@@ static void get_object_details(void
        int i;
        struct object_entry *entry;
  
 -      hash_objects();
        prepare_pack_ix();
        for (i = 0, entry = objects; i < nr_objects; i++, entry++)
                check_object(entry);
 -      for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 -              if (!entry->delta && entry->delta_child)
 -                      entry->delta_limit =
 -                              check_delta_limit(entry, 1);
 +
 +      if (nr_objects == nr_result) {
 +              /*
 +               * Depth of objects that depend on the entry -- this
 +               * is subtracted from depth-max to break too deep
 +               * delta chain because of delta data reusing.
 +               * However, we loosen this restriction when we know we
 +               * are creating a thin pack -- it will have to be
 +               * expanded on the other end anyway, so do not
 +               * artificially cut the delta chain and let it go as
 +               * deep as it wants.
 +               */
 +              for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 +                      if (!entry->delta && entry->delta_child)
 +                              entry->delta_limit =
 +                                      check_delta_limit(entry, 1);
 +      }
  }
  
  typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
@@@ -765,24 -598,6 +765,24 @@@ static int sha1_sort(const struct objec
        return memcmp(a->sha1, b->sha1, 20);
  }
  
 +static struct object_entry **create_final_object_list(void)
 +{
 +      struct object_entry **list;
 +      int i, j;
 +
 +      for (i = nr_result = 0; i < nr_objects; i++)
 +              if (!objects[i].preferred_base)
 +                      nr_result++;
 +      list = xmalloc(nr_result * sizeof(struct object_entry *));
 +      for (i = j = 0; i < nr_objects; i++) {
 +              if (!objects[i].preferred_base)
 +                      list[j++] = objects + i;
 +      }
 +      current_sort = sha1_sort;
 +      qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
 +      return list;
 +}
 +
  static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
  {
        if (a->type < b->type)
                return -1;
        if (a->hash > b->hash)
                return 1;
 +      if (a->preferred_base < b->preferred_base)
 +              return -1;
 +      if (a->preferred_base > b->preferred_base)
 +              return 1;
        if (a->size < b->size)
                return -1;
        if (a->size > b->size)
@@@ -829,15 -640,9 +829,15 @@@ static int try_delta(struct unpacked *c
        if (cur_entry->type != old_entry->type)
                return -1;
  
 -      /* If the current object is at edge, take the depth the objects
 -       * that depend on the current object into account -- otherwise
 -       * they would become too deep.
 +      /* We do not compute delta to *create* objects we are not
 +       * going to pack.
 +       */
 +      if (cur_entry->preferred_base)
 +              return -1;
 +
 +      /* If the current object is at pack edge, take the depth the
 +       * objects that depend on the current object into account --
 +       * otherwise they would become too deep.
         */
        if (cur_entry->delta_child) {
                if (max_depth <= cur_entry->delta_limit)
        }
  
        size = cur_entry->size;
 -      if (size < 50)
 -              return -1;
        oldsize = old_entry->size;
        sizediff = oldsize > size ? oldsize - size : size - oldsize;
 -      if (sizediff > size / 8)
 +
 +      if (size < 50)
                return -1;
        if (old_entry->depth >= max_depth)
                return 0;
@@@ -894,7 -700,7 +894,7 @@@ static void find_deltas(struct object_e
        i = nr_objects;
        idx = 0;
        if (progress)
 -              fprintf(stderr, "Deltifying %d objects.\n", nr_objects);
 +              fprintf(stderr, "Deltifying %d objects.\n", nr_result);
  
        while (--i >= 0) {
                struct object_entry *entry = list[i];
                char type[10];
                int j;
  
 -              processed++;
 +              if (!entry->preferred_base)
 +                      processed++;
 +
                if (progress) {
 -                      unsigned percent = processed * 100 / nr_objects;
 +                      unsigned percent = processed * 100 / nr_result;
                        if (percent != last_percent || progress_update) {
                                fprintf(stderr, "%4u%% (%u/%u) done\r",
 -                                      percent, processed, nr_objects);
 +                                      percent, processed, nr_result);
                                progress_update = 0;
                                last_percent = percent;
                        }
                        if (try_delta(n, m, depth) < 0)
                                break;
                }
 +#if 0
 +              /* if we made n a delta, and if n is already at max
 +               * depth, leaving it in the window is pointless.  we
 +               * should evict it first.
 +               * ... in theory only; somehow this makes things worse.
 +               */
 +              if (entry->delta && depth <= entry->depth)
 +                      continue;
 +#endif
                idx++;
                if (idx >= window)
                        idx = 0;
@@@ -1111,6 -906,8 +1111,6 @@@ int main(int argc, char **argv
        }
  
        for (;;) {
 -              unsigned int hash;
 -              char *p;
                unsigned char sha1[20];
  
                if (!fgets(line, sizeof(line), stdin)) {
                                break;
                        if (!ferror(stdin))
                                die("fgets returned NULL, not EOF, not error!");
-                       if (errno == EINTR)
-                               continue;
-                       die("fgets: %s", strerror(errno));
+                       if (errno != EINTR)
+                               die("fgets: %s", strerror(errno));
+                       clearerr(stdin);
+                       continue;
                }
  
 -              if (progress_update) {
 -                      fprintf(stderr, "Counting objects...%d\r", nr_objects);
 -                      progress_update = 0;
 +              if (line[0] == '-') {
 +                      if (get_sha1_hex(line+1, sha1))
 +                              die("expected edge sha1, got garbage:\n %s",
 +                                  line+1);
 +                      add_preferred_base(sha1);
 +                      continue;
                }
                if (get_sha1_hex(line, sha1))
                        die("expected sha1, got garbage:\n %s", line);
 -              hash = 0;
 -              p = line+40;
 -              while (*p) {
 -                      unsigned char c = *p++;
 -                      if (isspace(c))
 -                              continue;
 -                      hash = hash * 11 + c;
 -              }
 -              add_object_entry(sha1, hash);
 +              add_object_entry(sha1, name_hash(NULL, line+41), 0);
        }
        if (progress)
                fprintf(stderr, "Done counting %d objects.\n", nr_objects);
 -      if (non_empty && !nr_objects)
 +      sorted_by_sha = create_final_object_list();
 +      if (non_empty && !nr_result)
                return 0;
  
 -      sorted_by_sha = create_sorted_list(sha1_sort);
        SHA1_Init(&ctx);
        list = sorted_by_sha;
 -      for (i = 0; i < nr_objects; i++) {
 +      for (i = 0; i < nr_result; i++) {
                struct object_entry *entry = *list++;
                SHA1_Update(&ctx, entry->sha1, 20);
        }
        SHA1_Final(object_list_sha1, &ctx);
 +      if (progress && (nr_objects != nr_result))
 +              fprintf(stderr, "Result has %d objects.\n", nr_result);
  
        if (reuse_cached_pack(object_list_sha1, pack_to_stdout))
                ;
        else {
 -              prepare_pack(window, depth);
 +              if (nr_result)
 +                      prepare_pack(window, depth);
                if (progress && pack_to_stdout) {
                        /* the other end usually displays progress itself */
                        struct itimerval v = {{0,},};
        }
        if (progress)
                fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
 -                      nr_objects, written, written_delta, reused, reused_delta);
 +                      nr_result, written, written_delta, reused, reused_delta);
        return 0;
  }
diff --combined read-tree.c
@@@ -273,10 -273,26 +273,26 @@@ static void unlink_entry(char *name
  
  static void progress_interval(int signum)
  {
-       signal(SIGALRM, progress_interval);
        progress_update = 1;
  }
  
+ static void setup_progress_signal(void)
+ {
+       struct sigaction sa;
+       struct itimerval v;
+       memset(&sa, 0, sizeof(sa));
+       sa.sa_handler = progress_interval;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       sigaction(SIGALRM, &sa, NULL);
+       v.it_interval.tv_sec = 1;
+       v.it_interval.tv_usec = 0;
+       v.it_value = v.it_interval;
+       setitimer(ITIMER_REAL, &v, NULL);
+ }
  static void check_updates(struct cache_entry **src, int nr)
  {
        static struct checkout state = {
        unsigned last_percent = 200, cnt = 0, total = 0;
  
        if (update && verbose_update) {
-               struct itimerval v;
                for (total = cnt = 0; cnt < nr; cnt++) {
                        struct cache_entry *ce = src[cnt];
                        if (!ce->ce_mode || ce->ce_flags & mask)
                        total = 0;
  
                if (total) {
-                       v.it_interval.tv_sec = 1;
-                       v.it_interval.tv_usec = 0;
-                       v.it_value = v.it_interval;
-                       signal(SIGALRM, progress_interval);
-                       setitimer(ITIMER_REAL, &v, NULL);
                        fprintf(stderr, "Checking files out...\n");
+                       setup_progress_signal();
                        progress_update = 1;
                }
                cnt = 0;
                if (ce->ce_flags & mask) {
                        ce->ce_flags &= ~mask;
                        if (update)
 -                              checkout_entry(ce, &state);
 +                              checkout_entry(ce, &state, NULL);
                }
        }
        if (total) {
-               fputc('\n', stderr);
                signal(SIGALRM, SIG_IGN);
+               fputc('\n', stderr);
        }
  }
  
@@@ -404,7 -414,7 +414,7 @@@ static void verify_uptodate(struct cach
                return;
  
        if (!lstat(ce->name, &st)) {
 -              unsigned changed = ce_match_stat(ce, &st);
 +              unsigned changed = ce_match_stat(ce, &st, 1);
                if (!changed)
                        return;
                errno = 0;
@@@ -706,7 -716,7 +716,7 @@@ static int read_cache_unmerged(void
        return deleted;
  }
  
 -static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u | -i] <sha1> [<sha2> [<sha3>]])";
 +static const char read_tree_usage[] = "git-read-tree (<sha> | -m [--aggressive] [-u | -i] <sha1> [<sha2> [<sha3>]])";
  
  static struct cache_file cache_file;
  
@@@ -717,7 -727,6 +727,7 @@@ int main(int argc, char **argv
        merge_fn_t fn = NULL;
  
        setup_git_directory();
 +      git_config(git_default_config);
  
        newfd = hold_index_file_for_update(&cache_file, get_index_file());
        if (newfd < 0)