From 26125f6b9be8dac31f56bf3da60dfa0df6dc0b59 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Wed, 22 Feb 2006 11:16:38 -0800
Subject: detect broken alternates.

The real problem triggered an earlier fix was that an alternate
entry was pointing at a removed directory.  Complaining on
object/pack directory that cannot be opendir-ed produces noise
in an ancient repository that does not have object/pack
directory and has never been packed.

Detect the real user error and report it.  Also if opendir
failed for other reasons (e.g. no read permissions), report that
as well.

Spotted by Andrew Vasquez <andrew.vasquez@qlogic.com>.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/sha1_file.c b/sha1_file.c
index f08b1d6..c08da35 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -247,6 +247,7 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 		for ( ; cp < ep && *cp != sep; cp++)
 			;
 		if (last != cp) {
+			struct stat st;
 			struct alternate_object_database *alt;
 			/* 43 = 40-byte + 2 '/' + terminating NUL */
 			int pfxlen = cp - last;
@@ -269,9 +270,19 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 			}
 			else
 				memcpy(ent->base, last, pfxlen);
+
 			ent->name = ent->base + pfxlen + 1;
-			ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
-			ent->base[entlen-1] = 0;
+			ent->base[pfxlen + 3] = '/';
+			ent->base[pfxlen] = ent->base[entlen-1] = 0;
+
+			/* Detect cases where alternate disappeared */
+			if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
+				error("object directory %s does not exist; "
+				      "check .git/objects/info/alternates.",
+				      ent->base);
+				goto bad;
+			}
+			ent->base[pfxlen] = '/';
 
 			/* Prevent the common mistake of listing the same
 			 * thing twice, or object directory itself.
@@ -552,7 +563,9 @@ static void prepare_packed_git_one(char *objdir, int local)
 	len = strlen(path);
 	dir = opendir(path);
 	if (!dir) {
-		fprintf(stderr, "unable to open object pack directory: %s: %s\n", path, strerror(errno));
+		if (errno != ENOENT)
+			error("unable to open object pack directory: %s: %s\n",
+			      path, strerror(errno));
 		return;
 	}
 	path[len++] = '/';
-- 
cgit v0.10.2-6-g49f6


From 3f9ac8d259fb919e001671c5e403e5fceaabf0d8 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Wed, 15 Feb 2006 17:34:29 -0800
Subject: pack-objects: reuse data from existing packs.

When generating a new pack, notice if we have already needed
objects in existing packs.  If an object is stored deltified,
and its base object is also what we are going to pack, then
reuse the existing deltified representation unconditionally,
bypassing all the expensive find_deltas() and try_deltas()
calls.

Also, notice if what we are going to write out exactly match
what is already in an existing pack (either deltified or just
compressed).  In such a case, we can just copy it instead of
going through the usual uncompressing & recompressing cycle.

Without this patch, in linux-2.6 repository with about 1500
loose objects and a single mega pack:

    $ git-rev-list --objects v2.6.16-rc3 >RL
    $ wc -l RL
    184141 RL
    $ time git-pack-objects p <RL
    Generating pack...
    Done counting 184141 objects.
    Packing 184141 objects....................
    a1fc7b3e537fcb9b3c46b7505df859f0a11e79d2

    real    12m4.323s
    user    11m2.560s
    sys     0m55.950s

With this patch, the same input:

    $ time ../git.junio/git-pack-objects q <RL
    Generating pack...
    Done counting 184141 objects.
    Packing 184141 objects.....................
    a1fc7b3e537fcb9b3c46b7505df859f0a11e79d2
    Total 184141, written 184141, reused 182441

    real    1m2.608s
    user    0m55.090s
    sys     0m1.830s

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-objects.c b/pack-objects.c
index c5a5e61..70fb2af 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -9,15 +9,31 @@ static const char pack_usage[] = "git-pack-objects [-q] [--non-empty] [--local]
 
 struct object_entry {
 	unsigned char sha1[20];
-	unsigned long size;
-	unsigned long offset;
-	unsigned int depth;
-	unsigned int hash;
+	unsigned long size;	/* uncompressed size */
+	unsigned long offset;	/* offset into the final pack file (nonzero if already written) */
+	unsigned int depth;	/* delta depth */
+	unsigned int hash;	/* name hint hash */
 	enum object_type type;
-	unsigned long delta_size;
-	struct object_entry *delta;
+	unsigned long delta_size;	/* delta data size (uncompressed) */
+	struct object_entry *delta;	/* delta base object */
+	struct packed_git *in_pack; 	/* already in pack */
+	enum object_type in_pack_type;	/* could be delta */
+	unsigned int in_pack_offset;
 };
 
+/*
+ * Objects we are going to pack are colected in objects array (dynamically
+ * expanded).  nr_objects & nr_alloc controls this array.  They are stored
+ * in the order we see -- typically rev-list --objects order that gives us
+ * nice "minimum seek" order.
+ *
+ * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
+ * elements in the objects array.  The former is used to build the pack
+ * index (lists object names in the ascending order to help offset lookup),
+ * and the latter is used to group similar things together by try_delta()
+ * heuristics.
+ */
+
 static unsigned char object_list_sha1[20];
 static int non_empty = 0;
 static int local = 0;
@@ -29,6 +45,135 @@ static const char *base_name;
 static unsigned char pack_file_sha1[20];
 static int progress = 1;
 
+/*
+ * The object names in objects array are hashed with this hashtable,
+ * to help looking up the entry by object name.  Binary search from
+ * sorted_by_sha is also possible but this was easier to code and faster.
+ * This hashtable is built after all the objects are seen.
+ */
+static int *object_ix = NULL;
+static int object_ix_hashsz = 0;
+
+/*
+ * Pack index for existing packs give us easy access to the offsets into
+ * corresponding pack file where each object's data starts, but the entries
+ * do not store the size of the compressed representation (uncompressed
+ * size is easily available by examining the pack entry header).  We build
+ * a hashtable of existing packs (pack_revindex), and keep reverse index
+ * here -- pack index file is sorted by object name mapping to offset; this
+ * pack_revindex[].revindex array is an ordered list of offsets, so if you
+ * know the offset of an object, next offset is where its packed
+ * representation ends.
+ */
+struct pack_revindex {
+	struct packed_git *p;
+	unsigned long *revindex;
+} *pack_revindex = NULL;
+static int pack_revindex_hashsz = 0;
+
+/*
+ * stats
+ */
+static int written = 0;
+static int reused = 0;
+
+static int pack_revindex_ix(struct packed_git *p)
+{
+	unsigned int ui = (unsigned int) p;
+	int i;
+
+	ui = ui ^ (ui >> 16); /* defeat structure alignment */
+	i = (int)(ui % pack_revindex_hashsz);
+	while (pack_revindex[i].p) {
+		if (pack_revindex[i].p == p)
+			return i;
+		if (++i == pack_revindex_hashsz)
+			i = 0;
+	}
+	return -1 - i;
+}
+
+static void prepare_pack_ix(void)
+{
+	int num;
+	struct packed_git *p;
+	for (num = 0, p = packed_git; p; p = p->next)
+		num++;
+	if (!num)
+		return;
+	pack_revindex_hashsz = num * 11;
+	pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
+	for (p = packed_git; p; p = p->next) {
+		num = pack_revindex_ix(p);
+		num = - 1 - num;
+		pack_revindex[num].p = p;
+	}
+	/* revindex elements are lazily initialized */
+}
+
+static int cmp_offset(const void *a_, const void *b_)
+{
+	unsigned long a = *(unsigned long *) a_;
+	unsigned long b = *(unsigned long *) b_;
+	if (a < b)
+		return -1;
+	else if (a == b)
+		return 0;
+	else
+		return 1;
+}
+
+/*
+ * Ordered list of offsets of objects in the pack.
+ */
+static void prepare_pack_revindex(struct pack_revindex *rix)
+{
+	struct packed_git *p = rix->p;
+	int num_ent = num_packed_objects(p);
+	int i;
+	void *index = p->index_base + 256;
+
+	rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
+	for (i = 0; i < num_ent; i++) {
+		long hl = *((long *)(index + 24 * i));
+		rix->revindex[i] = ntohl(hl);
+	}
+	/* This knows the pack format -- the 20-byte trailer
+	 * follows immediately after the last object data.
+	 */
+	rix->revindex[num_ent] = p->pack_size - 20;
+	qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset);
+}
+
+static unsigned long find_packed_object_size(struct packed_git *p,
+					     unsigned long ofs)
+{
+	int num;
+	int lo, hi;
+	struct pack_revindex *rix;
+	unsigned long *revindex;
+	num = pack_revindex_ix(p);
+	if (num < 0)
+		die("internal error: pack revindex uninitialized");
+	rix = &pack_revindex[num];
+	if (!rix->revindex)
+		prepare_pack_revindex(rix);
+	revindex = rix->revindex;
+	lo = 0;
+	hi = num_packed_objects(p) + 1;
+	do {
+		int mi = (lo + hi) / 2;
+		if (revindex[mi] == ofs) {
+			return revindex[mi+1] - ofs;
+		}
+		else if (ofs < revindex[mi])
+			hi = mi;
+		else
+			lo = mi + 1;
+	} while (lo < hi);
+	die("internal error: pack revindex corrupt");
+}
+
 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 {
 	unsigned long othersize, delta_size;
@@ -78,35 +223,52 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry
 {
 	unsigned long size;
 	char type[10];
-	void *buf = read_sha1_file(entry->sha1, type, &size);
+	void *buf;
 	unsigned char header[10];
 	unsigned hdrlen, datalen;
 	enum object_type obj_type;
 
-	if (!buf)
-		die("unable to read %s", sha1_to_hex(entry->sha1));
-	if (size != entry->size)
-		die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
-
-	/*
-	 * The object header is a byte of 'type' followed by zero or
-	 * more bytes of length.  For deltas, the 20 bytes of delta sha1
-	 * follows that.
-	 */
 	obj_type = entry->type;
-	if (entry->delta) {
-		buf = delta_against(buf, size, entry);
-		size = entry->delta_size;
-		obj_type = OBJ_DELTA;
+	if (!entry->in_pack ||
+	    (obj_type != entry->in_pack_type)) {
+		buf = read_sha1_file(entry->sha1, type, &size);
+		if (!buf)
+			die("unable to read %s", sha1_to_hex(entry->sha1));
+		if (size != entry->size)
+			die("object %s size inconsistency (%lu vs %lu)",
+			    sha1_to_hex(entry->sha1), size, entry->size);
+		if (entry->delta) {
+			buf = delta_against(buf, size, entry);
+			size = entry->delta_size;
+			obj_type = OBJ_DELTA;
+		}
+		/*
+		 * The object header is a byte of 'type' followed by zero or
+		 * more bytes of length.  For deltas, the 20 bytes of delta
+		 * sha1 follows that.
+		 */
+		hdrlen = encode_header(obj_type, size, header);
+		sha1write(f, header, hdrlen);
+
+		if (entry->delta) {
+			sha1write(f, entry->delta, 20);
+			hdrlen += 20;
+		}
+		datalen = sha1write_compressed(f, buf, size);
+		free(buf);
 	}
-	hdrlen = encode_header(obj_type, size, header);
-	sha1write(f, header, hdrlen);
-	if (entry->delta) {
-		sha1write(f, entry->delta, 20);
-		hdrlen += 20;
+	else {
+		struct packed_git *p = entry->in_pack;
+		use_packed_git(p);
+
+		datalen = find_packed_object_size(p, entry->in_pack_offset);
+		buf = p->pack_base + entry->in_pack_offset;
+		sha1write(f, buf, datalen);
+		unuse_packed_git(p);
+		hdrlen = 0; /* not really */
+		reused++;
 	}
-	datalen = sha1write_compressed(f, buf, size);
-	free(buf);
+	written++;
 	return hdrlen + datalen;
 }
 
@@ -148,8 +310,6 @@ static void write_pack_file(void)
 		offset = write_one(f, objects + i, offset);
 
 	sha1close(f, pack_file_sha1, 1);
-	mb = offset >> 20;
-	offset &= 0xfffff;
 }
 
 static void write_index_file(void)
@@ -196,18 +356,21 @@ static int add_object_entry(unsigned char *sha1, unsigned int hash)
 {
 	unsigned int idx = nr_objects;
 	struct object_entry *entry;
-
-	if (incremental || local) {
-		struct packed_git *p;
-
-		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;
+	struct packed_git *p;
+	unsigned int found_offset;
+	struct packed_git *found_pack;
+
+	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;
 			}
 		}
 	}
@@ -221,30 +384,107 @@ static int add_object_entry(unsigned char *sha1, unsigned int hash)
 	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;
+	}
 	nr_objects = idx+1;
 	return 1;
 }
 
+static int locate_object_entry_hash(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(unsigned char *sha1)
+{
+	int i = locate_object_entry_hash(sha1);
+	if (0 <= i)
+		return &objects[object_ix[i]-1];
+	return NULL;
+}
+
 static void check_object(struct object_entry *entry)
 {
 	char type[20];
 
-	if (!sha1_object_info(entry->sha1, type, &entry->size)) {
-		if (!strcmp(type, "commit")) {
-			entry->type = OBJ_COMMIT;
-		} else if (!strcmp(type, "tree")) {
-			entry->type = OBJ_TREE;
-		} else if (!strcmp(type, "blob")) {
-			entry->type = OBJ_BLOB;
-		} else if (!strcmp(type, "tag")) {
-			entry->type = OBJ_TAG;
-		} else
-			die("unable to pack object %s of type %s",
-			    sha1_to_hex(entry->sha1), type);
+	if (entry->in_pack) {
+		/* Check if it is delta, and the base is also an object
+		 * we are going to pack.  If so we will reuse the existing
+		 * delta.
+		 */
+		unsigned char base[20];
+		unsigned long size;
+		struct object_entry *base_entry;
+		if (!check_reuse_pack_delta(entry->in_pack,
+					    entry->in_pack_offset,
+					    base, &size,
+					    &entry->in_pack_type) &&
+		    (base_entry = locate_object_entry(base))) {
+			/* We do not know depth at this point, but it
+			 * does not matter.  Getting delta_chain_length
+			 * with packed_object_info_detail() is not so
+			 * expensive, so we could do that later if we
+			 * wanted to.  Calling sha1_object_info to get
+			 * the true size (and later an uncompressed
+			 * representation) of deeply deltified object
+			 * is quite expensive.
+			 */
+			entry->depth = 1;
+			/* uncompressed size */
+			entry->size = entry->delta_size = size;
+			entry->delta = base_entry;
+			entry->type = OBJ_DELTA;
+			return;
+		}
+		/* Otherwise we would do the usual */
 	}
-	else
+
+	if (sha1_object_info(entry->sha1, type, &entry->size))
 		die("unable to get type of object %s",
 		    sha1_to_hex(entry->sha1));
+
+	if (!strcmp(type, "commit")) {
+		entry->type = OBJ_COMMIT;
+	} else if (!strcmp(type, "tree")) {
+		entry->type = OBJ_TREE;
+	} else if (!strcmp(type, "blob")) {
+		entry->type = OBJ_BLOB;
+	} else if (!strcmp(type, "tag")) {
+		entry->type = OBJ_TAG;
+	} else
+		die("unable to pack object %s of type %s",
+		    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 void get_object_details(void)
@@ -252,6 +492,8 @@ static void get_object_details(void)
 	int i;
 	struct object_entry *entry = objects;
 
+	hash_objects();
+	prepare_pack_ix();
 	for (i = 0; i < nr_objects; i++)
 		check_object(entry++);
 }
@@ -382,6 +624,13 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 			eye_candy -= nr_objects / 20;
 			fputc('.', stderr);
 		}
+
+		if (entry->delta)
+			/* This happens if we decided to reuse existing
+			 * delta from a pack.
+			 */
+			continue;
+
 		free(n->data);
 		n->entry = entry;
 		n->data = read_sha1_file(entry->sha1, type, &size);
@@ -411,10 +660,12 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 
 static void prepare_pack(int window, int depth)
 {
-	get_object_details();
-
 	if (progress)
 		fprintf(stderr, "Packing %d objects", nr_objects);
+	get_object_details();
+	if (progress)
+		fprintf(stderr, ".");
+
 	sorted_by_type = create_sorted_list(type_size_sort);
 	if (window && depth)
 		find_deltas(sorted_by_type, window+1, depth);
@@ -599,5 +850,7 @@ int main(int argc, char **argv)
 			puts(sha1_to_hex(object_list_sha1));
 		}
 	}
+	fprintf(stderr, "Total %d, written %d, reused %d\n",
+		nr_objects, written, reused);
 	return 0;
 }
diff --git a/pack.h b/pack.h
index 9dafa2b..694e0c5 100644
--- a/pack.h
+++ b/pack.h
@@ -29,5 +29,7 @@ struct pack_header {
 };
 
 extern int verify_pack(struct packed_git *, int);
-
+extern int check_reuse_pack_delta(struct packed_git *, unsigned long,
+				  unsigned char *, unsigned long *,
+				  enum object_type *);
 #endif
diff --git a/sha1_file.c b/sha1_file.c
index c08da35..f4b1089 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -841,6 +841,25 @@ static unsigned long unpack_object_header(struct packed_git *p, unsigned long of
 	return offset;
 }
 
+int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
+			   unsigned char *base, unsigned long *sizep,
+			   enum object_type *kindp)
+{
+	unsigned long ptr;
+	int status = -1;
+
+	use_packed_git(p);
+	ptr = offset;
+	ptr = unpack_object_header(p, ptr, kindp, sizep);
+	if (*kindp != OBJ_DELTA)
+		goto done;
+	memcpy(base, p->pack_base + ptr, 20);
+	status = 0;
+ done:
+	unuse_packed_git(p);
+	return status;
+}
+
 void packed_object_info_detail(struct pack_entry *e,
 			       char *type,
 			       unsigned long *size,
-- 
cgit v0.10.2-6-g49f6


From ab7cd7bb8c02dc40ca3a909653e8f56226f9e440 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Thu, 16 Feb 2006 11:55:51 -0800
Subject: pack-objects: finishing touches.

This introduces --no-reuse-delta option to disable reusing of
existing delta, which is a large part of the optimization
introduced by this series.  This may become necessary if
repeated repacking makes delta chain too long.  With this, the
output of the command becomes identical to that of the older
implementation.  But the performance suffers greatly.

It still allows reusing non-deltified representations; there is
no point uncompressing and recompressing the whole text.

It also adds a couple more statistics output, while squelching
it under -q flag, which the last round forgot to do.

  $ time old-git-pack-objects --stdout >/dev/null <RL
  Generating pack...
  Done counting 184141 objects.
  Packing 184141 objects....................
  real    12m8.530s       user    11m1.450s       sys     0m57.920s
  $ time git-pack-objects --stdout >/dev/null <RL
  Generating pack...
  Done counting 184141 objects.
  Packing 184141 objects.....................
  Total 184141, written 184141 (delta 138297), reused 178833 (delta 134081)
  real    0m59.549s       user    0m56.670s       sys     0m2.400s
  $ time git-pack-objects --stdout --no-reuse-delta >/dev/null <RL
  Generating pack...
  Done counting 184141 objects.
  Packing 184141 objects.....................
  Total 184141, written 184141 (delta 134833), reused 47904 (delta 0)
  real    11m13.830s      user    9m45.240s       sys     0m44.330s

There is one remaining issue when --no-reuse-delta option is not
used.  It can create delta chains that are deeper than specified.

    A<--B<--C<--D   E   F   G

Suppose we have a delta chain A to D (A is stored in full either
in a pack or as a loose object. B is depth1 delta relative to A,
C is depth2 delta relative to B...) with loose objects E, F, G.
And we are going to pack all of them.

B, C and D are left as delta against A, B and C respectively.
So A, E, F, and G are examined for deltification, and let's say
we decided to keep E expanded, and store the rest as deltas like
this:

    E<--F<--G<--A

Oops.  We ended up making D a bit too deep, didn't we?  B, C and
D form a chain on top of A!

This is because we did not know what the final depth of A would
be, when we checked objects and decided to keep the existing
delta.  Unfortunately, deferring the decision until just before
the deltification is not an option.  To be able to make B, C,
and D candidates for deltification with the rest, we need to
know the type and final unexpanded size of them, but the major
part of the optimization comes from the fact that we do not read
the delta data to do so -- getting the final size is quite an
expensive operation.

To prevent this from happening, we should keep A from being
deltified.  But how would we tell that, cheaply?

To do this most precisely, after check_object() runs, each
object that is used as the base object of some existing delta
needs to be marked with the maximum depth of the objects we
decided to keep deltified (in this case, D is depth 3 relative
to A, so if no other delta chain that is longer than 3 based on
A exists, mark A with 3).  Then when attempting to deltify A, we
would take that number into account to see if the final delta
chain that leads to D becomes too deep.

However, this is a bit cumbersome to compute, so we would cheat
and reduce the maximum depth for A arbitrarily to depth/4 in
this implementation.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt
index 2d67d39..4cb2e83 100644
--- a/Documentation/git-pack-objects.txt
+++ b/Documentation/git-pack-objects.txt
@@ -8,7 +8,10 @@ git-pack-objects - Create a packed archive of objects.
 
 SYNOPSIS
 --------
-'git-pack-objects' [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list
+[verse]
+'git-pack-objects' [-q] [--no-reuse-delta] [--non-empty]
+	[--local] [--incremental] [--window=N] [--depth=N]
+	{--stdout | base-name} < object-list
 
 
 DESCRIPTION
@@ -32,6 +35,10 @@ Placing both in the pack/ subdirectory of $GIT_OBJECT_DIRECTORY (or
 any of the directories on $GIT_ALTERNATE_OBJECT_DIRECTORIES)
 enables git to read from such an archive.
 
+In a packed archive, an object is either stored as a compressed
+whole, or as a difference from some other object.  The latter is
+often called a delta.
+
 
 OPTIONS
 -------
@@ -74,6 +81,18 @@ base-name::
         Only create a packed archive if it would contain at
         least one object.
 
+-q::
+	This flag makes the command not to report its progress
+	on the standard error stream.
+
+--no-reuse-delta::
+	When creating a packed archive in a repository that
+	has existing packs, the command reuses existing deltas.
+	This sometimes results in a slightly suboptimal pack.
+	This flag tells the command not to reuse existing deltas
+	but compute them from scratch.
+
+
 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>
diff --git a/pack-objects.c b/pack-objects.c
index 70fb2af..38e1c99 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -5,7 +5,7 @@
 #include "csum-file.h"
 #include <sys/time.h>
 
-static const char pack_usage[] = "git-pack-objects [-q] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
+static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 
 struct object_entry {
 	unsigned char sha1[20];
@@ -14,10 +14,11 @@ struct object_entry {
 	unsigned int depth;	/* delta depth */
 	unsigned int hash;	/* name hint hash */
 	enum object_type type;
+	unsigned char edge;	/* reused delta chain points at this entry. */
+	enum object_type in_pack_type;	/* could be delta */
 	unsigned long delta_size;	/* delta data size (uncompressed) */
 	struct object_entry *delta;	/* delta base object */
 	struct packed_git *in_pack; 	/* already in pack */
-	enum object_type in_pack_type;	/* could be delta */
 	unsigned int in_pack_offset;
 };
 
@@ -36,6 +37,7 @@ struct object_entry {
 
 static unsigned char object_list_sha1[20];
 static int non_empty = 0;
+static int no_reuse_delta = 0;
 static int local = 0;
 static int incremental = 0;
 static struct object_entry **sorted_by_sha, **sorted_by_type;
@@ -75,7 +77,9 @@ static int pack_revindex_hashsz = 0;
  * stats
  */
 static int written = 0;
+static int written_delta = 0;
 static int reused = 0;
+static int reused_delta = 0;
 
 static int pack_revindex_ix(struct packed_git *p)
 {
@@ -227,10 +231,23 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry
 	unsigned char header[10];
 	unsigned hdrlen, datalen;
 	enum object_type obj_type;
+	int to_reuse = 0;
 
 	obj_type = entry->type;
-	if (!entry->in_pack ||
-	    (obj_type != entry->in_pack_type)) {
+	if (! entry->in_pack)
+		to_reuse = 0;	/* can't reuse what we don't have */
+	else if (obj_type == OBJ_DELTA)
+		to_reuse = 1;	/* check_object() decided it for us */
+	else if (obj_type != entry->in_pack_type)
+		to_reuse = 0;	/* pack has delta which is unusable */
+	else if (entry->delta)
+		to_reuse = 0;	/* we want to pack afresh */
+	else
+		to_reuse = 1;	/* we have it in-pack undeltified,
+				 * and we do not need to deltify it.
+				 */
+
+	if (! to_reuse) {
 		buf = read_sha1_file(entry->sha1, type, &size);
 		if (!buf)
 			die("unable to read %s", sha1_to_hex(entry->sha1));
@@ -266,8 +283,12 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry
 		sha1write(f, buf, datalen);
 		unuse_packed_git(p);
 		hdrlen = 0; /* not really */
+		if (obj_type == OBJ_DELTA)
+			reused_delta++;
 		reused++;
 	}
+	if (obj_type == OBJ_DELTA)
+		written_delta++;
 	written++;
 	return hdrlen + datalen;
 }
@@ -294,7 +315,6 @@ static void write_pack_file(void)
 	int i;
 	struct sha1file *f;
 	unsigned long offset;
-	unsigned long mb;
 	struct pack_header hdr;
 
 	if (!base_name)
@@ -357,10 +377,9 @@ static int add_object_entry(unsigned char *sha1, unsigned int hash)
 	unsigned int idx = nr_objects;
 	struct object_entry *entry;
 	struct packed_git *p;
-	unsigned int found_offset;
-	struct packed_git *found_pack;
+	unsigned int found_offset = 0;
+	struct packed_git *found_pack = NULL;
 
-	found_pack = NULL;
 	for (p = packed_git; p; p = p->next) {
 		struct pack_entry e;
 		if (find_pack_entry_one(sha1, &e, p)) {
@@ -420,32 +439,39 @@ static void check_object(struct object_entry *entry)
 	char type[20];
 
 	if (entry->in_pack) {
+		unsigned char base[20];
+		unsigned long size;
+		struct object_entry *base_entry;
+
+		/* We want in_pack_type even if we do not reuse delta.
+		 * There is no point not reusing non-delta representations.
+		 */
+		check_reuse_pack_delta(entry->in_pack,
+				       entry->in_pack_offset,
+				       base, &size,
+				       &entry->in_pack_type);
+
 		/* Check if it is delta, and the base is also an object
 		 * we are going to pack.  If so we will reuse the existing
 		 * delta.
 		 */
-		unsigned char base[20];
-		unsigned long size;
-		struct object_entry *base_entry;
-		if (!check_reuse_pack_delta(entry->in_pack,
-					    entry->in_pack_offset,
-					    base, &size,
-					    &entry->in_pack_type) &&
+		if (!no_reuse_delta &&
+		    entry->in_pack_type == OBJ_DELTA &&
 		    (base_entry = locate_object_entry(base))) {
-			/* We do not know depth at this point, but it
-			 * does not matter.  Getting delta_chain_length
-			 * with packed_object_info_detail() is not so
-			 * expensive, so we could do that later if we
-			 * wanted to.  Calling sha1_object_info to get
-			 * the true size (and later an uncompressed
-			 * representation) of deeply deltified object
-			 * is quite expensive.
+
+			/* Depth value does not matter - find_deltas()
+			 * will never consider reused delta as the
+			 * base object to deltify other objects
+			 * against, in order to avoid circular deltas.
 			 */
-			entry->depth = 1;
-			/* uncompressed size */
+
+			/* uncompressed size of the delta data */
 			entry->size = entry->delta_size = size;
 			entry->delta = base_entry;
 			entry->type = OBJ_DELTA;
+
+			base_entry->edge = 1;
+
 			return;
 		}
 		/* Otherwise we would do the usual */
@@ -568,6 +594,13 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	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.
+	 */
+	if (cur_entry->edge)
+		max_depth /= 4;
+
 	size = cur_entry->size;
 	if (size < 50)
 		return -1;
@@ -627,7 +660,7 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 
 		if (entry->delta)
 			/* This happens if we decided to reuse existing
-			 * delta from a pack.
+			 * delta from a pack.  "!no_reuse_delta &&" is implied.
 			 */
 			continue;
 
@@ -636,6 +669,7 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 		n->data = read_sha1_file(entry->sha1, type, &size);
 		if (size != entry->size)
 			die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
+
 		j = window;
 		while (--j > 0) {
 			unsigned int other_idx = idx + j;
@@ -664,7 +698,7 @@ static void prepare_pack(int window, int depth)
 		fprintf(stderr, "Packing %d objects", nr_objects);
 	get_object_details();
 	if (progress)
-		fprintf(stderr, ".");
+		fputc('.', stderr);
 
 	sorted_by_type = create_sorted_list(type_size_sort);
 	if (window && depth)
@@ -694,8 +728,9 @@ static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout)
 		}
 	}
 
-	fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
-		sha1_to_hex(sha1));
+	if (progress)
+		fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
+			sha1_to_hex(sha1));
 
 	if (pack_to_stdout) {
 		if (copy_fd(ifd, 1))
@@ -775,6 +810,10 @@ int main(int argc, char **argv)
 				progress = 0;
 				continue;
 			}
+			if (!strcmp("--no-reuse-delta", arg)) {
+				no_reuse_delta = 1;
+				continue;
+			}
 			if (!strcmp("--stdout", arg)) {
 				pack_to_stdout = 1;
 				continue;
@@ -850,7 +889,8 @@ int main(int argc, char **argv)
 			puts(sha1_to_hex(object_list_sha1));
 		}
 	}
-	fprintf(stderr, "Total %d, written %d, reused %d\n",
-		nr_objects, written, reused);
+	if (progress)
+		fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
+			nr_objects, written, written_delta, reused, reused_delta);
 	return 0;
 }
-- 
cgit v0.10.2-6-g49f6


From 4181bda1567fc749623eac1c81c2b07c882d63b3 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Thu, 16 Feb 2006 11:57:18 -0800
Subject: git-repack: allow passing a couple of flags to pack-objects.

A new flag -q makes underlying pack-objects less chatty.
A new flag -f forces delta to be recomputed from scratch.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt
index 9060fe8..6c0f792 100644
--- a/Documentation/git-repack.txt
+++ b/Documentation/git-repack.txt
@@ -9,7 +9,7 @@ objects into pack files.
 
 SYNOPSIS
 --------
-'git-repack' [-a] [-d] [-l] [-n]
+'git-repack' [-a] [-d] [-f] [-l] [-n] [-q]
 
 DESCRIPTION
 -----------
@@ -43,6 +43,14 @@ OPTIONS
         Pass the `--local` option to `git pack-objects`, see
         gitlink:git-pack-objects[1].
 
+-f::
+        Pass the `--no-reuse-delta` option to `git pack-objects`, see
+        gitlink:git-pack-objects[1].
+
+-q::
+        Pass the `-q` option to `git pack-objects`, see
+        gitlink:git-pack-objects[1].
+
 -n::
         Do not update the server information with
         `git update-server-info`.
diff --git a/git-repack.sh b/git-repack.sh
index 1fafb6e..3d6fec1 100755
--- a/git-repack.sh
+++ b/git-repack.sh
@@ -3,17 +3,20 @@
 # Copyright (c) 2005 Linus Torvalds
 #
 
-USAGE='[-a] [-d] [-l] [-n]'
+USAGE='[-a] [-d] [-f] [-l] [-n] [-q]'
 . git-sh-setup
 	
-no_update_info= all_into_one= remove_redundant= local=
+no_update_info= all_into_one= remove_redundant=
+local= quiet= no_reuse_delta=
 while case "$#" in 0) break ;; esac
 do
 	case "$1" in
 	-n)	no_update_info=t ;;
 	-a)	all_into_one=t ;;
 	-d)	remove_redundant=t ;;
-	-l)	local=t ;;
+	-q)	quiet=-q ;;
+	-f)	no_reuse_delta=--no-reuse-delta ;;
+	-l)	local=--local ;;
 	*)	usage ;;
 	esac
 	shift
@@ -39,9 +42,7 @@ case ",$all_into_one," in
 	    find . -type f \( -name '*.pack' -o -name '*.idx' \) -print`
 	;;
 esac
-if [ "$local" ]; then
-	pack_objects="$pack_objects --local"
-fi
+pack_objects="$pack_objects $local $quiet $no_reuse_delta"
 name=$(git-rev-list --objects $rev_list $(git-rev-parse $rev_parse) 2>&1 |
 	git-pack-objects --non-empty $pack_objects .tmp-pack) ||
 	exit 1
-- 
cgit v0.10.2-6-g49f6


From 15b4d577ae2e0117b7b5a4add2217442a8458812 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Fri, 17 Feb 2006 20:58:45 -0800
Subject: pack-objects: avoid delta chains that are too long.

This tries to rework the solution for the excess delta chain
problem. An earlier commit worked it around ``cheaply'', but
repeated repacking risks unbound growth of delta chains.

This version counts the length of delta chain we are reusing
from the existing pack, and makes sure a base object that has
sufficiently long delta chain does not get deltified.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-objects.c b/pack-objects.c
index 38e1c99..0c9f4c9 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -10,16 +10,22 @@ static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--no
 struct object_entry {
 	unsigned char sha1[20];
 	unsigned long size;	/* uncompressed size */
-	unsigned long offset;	/* offset into the final pack file (nonzero if already written) */
+	unsigned long offset;	/* offset into the final pack file;
+				 * nonzero if already written.
+				 */
 	unsigned int depth;	/* delta depth */
+	unsigned int delta_limit;	/* base adjustment for in-pack delta */
 	unsigned int hash;	/* name hint hash */
 	enum object_type type;
-	unsigned char edge;	/* reused delta chain points at this entry. */
 	enum object_type in_pack_type;	/* could be delta */
 	unsigned long delta_size;	/* delta data size (uncompressed) */
 	struct object_entry *delta;	/* delta base object */
 	struct packed_git *in_pack; 	/* already in pack */
 	unsigned int in_pack_offset;
+	struct object_entry *delta_child; /* delitified objects who bases me */
+	struct object_entry *delta_sibling; /* other deltified objects who
+					     * uses the same base as me
+					     */
 };
 
 /*
@@ -470,7 +476,8 @@ static void check_object(struct object_entry *entry)
 			entry->delta = base_entry;
 			entry->type = OBJ_DELTA;
 
-			base_entry->edge = 1;
+			entry->delta_sibling = base_entry->delta_child;
+			base_entry->delta_child = entry;
 
 			return;
 		}
@@ -513,15 +520,32 @@ static void hash_objects(void)
 	}
 }
 
+static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
+{
+	struct object_entry *child = me->delta_child;
+	unsigned int m = n;
+	while (child) {
+		unsigned int c = check_delta_limit(child, n + 1);
+		if (m < c)
+			m = c;
+		child = child->delta_sibling;
+	}
+	return m;
+}
+
 static void get_object_details(void)
 {
 	int i;
-	struct object_entry *entry = objects;
+	struct object_entry *entry;
 
 	hash_objects();
 	prepare_pack_ix();
-	for (i = 0; i < nr_objects; i++)
-		check_object(entry++);
+	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);
 }
 
 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
@@ -598,8 +622,11 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	 * that depend on the current object into account -- otherwise
 	 * they would become too deep.
 	 */
-	if (cur_entry->edge)
-		max_depth /= 4;
+	if (cur_entry->delta_child) {
+		if (max_depth <= cur_entry->delta_limit)
+			return 0;
+		max_depth -= cur_entry->delta_limit;
+	}
 
 	size = cur_entry->size;
 	if (size < 50)
-- 
cgit v0.10.2-6-g49f6


From 2fb4a21074cdd62ecdbb1fd491f743483275e2a4 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Sat, 18 Feb 2006 01:20:06 -0800
Subject: Make "empty ident" error message a bit more helpful.

It appears that some people who did not care about having bogus
names in their own commit messages are bitten by the recent
change to require a sane environment [*1*].

While it was a good idea to prevent people from using bogus
names to create commits and doing sign-offs, the error message
is not very informative.  This patch attempts to warn things
upfront and hint people how to fix their environments.

[Footnote]

*1* The thread is this one.

    http://marc.theaimsgroup.com/?t=113868084800004

    Especially this message.

    http://marc.theaimsgroup.com/?m=113932830015032

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/ident.c b/ident.c
index 23b8cfc..09d4d71 100644
--- a/ident.c
+++ b/ident.c
@@ -46,6 +46,15 @@ static void copy_gecos(struct passwd *w, char *name, int sz)
 
 }
 
+static const char au_env[] = "GIT_AUTHOR_NAME";
+static const char co_env[] = "GIT_COMMITTER_NAME";
+static const char env_hint[] =
+"\n*** Environment problem:\n"
+"*** Your name cannot be determined from your system services (gecos).\n"
+"*** You would need to set %s and %s\n"
+"*** environment variables; otherwise you won't be able to perform\n"
+"*** certain operations because of \"empty ident\" errors.\n\n";
+
 int setup_ident(void)
 {
 	int len;
@@ -57,6 +66,11 @@ int setup_ident(void)
 	/* Get the name ("gecos") */
 	copy_gecos(pw, git_default_name, sizeof(git_default_name));
 
+	if (!*git_default_name) {
+		if (!getenv(au_env) || !getenv(co_env))
+			fprintf(stderr, env_hint, au_env, co_env);
+	}
+
 	/* Make up a fake email address (name + '@' + hostname [+ '.' + domainname]) */
 	len = strlen(pw->pw_name);
 	if (len > sizeof(git_default_email)/2)
-- 
cgit v0.10.2-6-g49f6


From 589e4f93c7fc31d73da3d0764c71d939c9332442 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Sat, 18 Feb 2006 20:31:05 -0800
Subject: Delay "empty ident" errors until they really matter.

Previous one warned people upfront to encourage fixing their
environment early, but some people just use repositories and git
tools read-only without making any changes, and in such a case
there is not much point insisting on them having a usable ident.

This round attempts to move the error until either "git-var"
asks for the ident explicitly or "commit-tree" wants to use it.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/cache.h b/cache.h
index c255421..9f4adf5 100644
--- a/cache.h
+++ b/cache.h
@@ -246,8 +246,8 @@ void datestamp(char *buf, int bufsize);
 unsigned long approxidate(const char *);
 
 extern int setup_ident(void);
-extern const char *git_author_info(void);
-extern const char *git_committer_info(void);
+extern const char *git_author_info(int);
+extern const char *git_committer_info(int);
 
 struct checkout {
 	const char *base_dir;
diff --git a/commit-tree.c b/commit-tree.c
index b1c8dca..88871b0 100644
--- a/commit-tree.c
+++ b/commit-tree.c
@@ -118,8 +118,8 @@ int main(int argc, char **argv)
 		add_buffer(&buffer, &size, "parent %s\n", sha1_to_hex(parent_sha1[i]));
 
 	/* Person/date information */
-	add_buffer(&buffer, &size, "author %s\n", git_author_info());
-	add_buffer(&buffer, &size, "committer %s\n\n", git_committer_info());
+	add_buffer(&buffer, &size, "author %s\n", git_author_info(1));
+	add_buffer(&buffer, &size, "committer %s\n\n", git_committer_info(1));
 
 	/* And add the comment */
 	while (fgets(comment, sizeof(comment), stdin) != NULL)
diff --git a/ident.c b/ident.c
index 09d4d71..7c81fe8 100644
--- a/ident.c
+++ b/ident.c
@@ -46,15 +46,6 @@ static void copy_gecos(struct passwd *w, char *name, int sz)
 
 }
 
-static const char au_env[] = "GIT_AUTHOR_NAME";
-static const char co_env[] = "GIT_COMMITTER_NAME";
-static const char env_hint[] =
-"\n*** Environment problem:\n"
-"*** Your name cannot be determined from your system services (gecos).\n"
-"*** You would need to set %s and %s\n"
-"*** environment variables; otherwise you won't be able to perform\n"
-"*** certain operations because of \"empty ident\" errors.\n\n";
-
 int setup_ident(void)
 {
 	int len;
@@ -66,11 +57,6 @@ int setup_ident(void)
 	/* Get the name ("gecos") */
 	copy_gecos(pw, git_default_name, sizeof(git_default_name));
 
-	if (!*git_default_name) {
-		if (!getenv(au_env) || !getenv(co_env))
-			fprintf(stderr, env_hint, au_env, co_env);
-	}
-
 	/* Make up a fake email address (name + '@' + hostname [+ '.' + domainname]) */
 	len = strlen(pw->pw_name);
 	if (len > sizeof(git_default_email)/2)
@@ -170,8 +156,18 @@ static int copy(char *buf, int size, int offset, const char *src)
 	return offset;
 }
 
+static const char au_env[] = "GIT_AUTHOR_NAME";
+static const char co_env[] = "GIT_COMMITTER_NAME";
+static const char *env_hint =
+"\n*** Environment problem:\n"
+"*** Your name cannot be determined from your system services (gecos).\n"
+"*** You would need to set %s and %s\n"
+"*** environment variables; otherwise you won't be able to perform\n"
+"*** certain operations because of \"empty ident\" errors.\n"
+"*** Alternatively, you can use user.name configuration variable.\n\n";
+
 static const char *get_ident(const char *name, const char *email,
-			     const char *date_str)
+			     const char *date_str, int error_on_no_name)
 {
 	static char buffer[1000];
 	char date[50];
@@ -182,9 +178,14 @@ static const char *get_ident(const char *name, const char *email,
 	if (!email)
 		email = git_default_email;
 
-	if (!*name || !*email)
-		die("empty ident %s <%s> not allowed",
-		    name, email);
+	if (!*name) {
+		if (name == git_default_name && env_hint) {
+			fprintf(stderr, env_hint, au_env, co_env);
+			env_hint = NULL; /* warn only once, for "git-var -l" */
+		}
+		if (error_on_no_name)
+			die("empty ident %s <%s> not allowed", name, email);
+	}
 
 	strcpy(date, git_default_date);
 	if (date_str)
@@ -201,16 +202,18 @@ static const char *get_ident(const char *name, const char *email,
 	return buffer;
 }
 
-const char *git_author_info(void)
+const char *git_author_info(int error_on_no_name)
 {
 	return get_ident(getenv("GIT_AUTHOR_NAME"),
 			 getenv("GIT_AUTHOR_EMAIL"),
-			 getenv("GIT_AUTHOR_DATE"));
+			 getenv("GIT_AUTHOR_DATE"),
+			 error_on_no_name);
 }
 
-const char *git_committer_info(void)
+const char *git_committer_info(int error_on_no_name)
 {
 	return get_ident(getenv("GIT_COMMITTER_NAME"),
 			 getenv("GIT_COMMITTER_EMAIL"),
-			 getenv("GIT_COMMITTER_DATE"));
+			 getenv("GIT_COMMITTER_DATE"),
+			 error_on_no_name);
 }
diff --git a/var.c b/var.c
index 59da56d..a57a33b 100644
--- a/var.c
+++ b/var.c
@@ -12,7 +12,7 @@ static const char var_usage[] = "git-var [-l | <variable>]";
 
 struct git_var {
 	const char *name;
-	const char *(*read)(void);
+	const char *(*read)(int);
 };
 static struct git_var git_vars[] = {
 	{ "GIT_COMMITTER_IDENT", git_committer_info },
@@ -24,7 +24,7 @@ static void list_vars(void)
 {
 	struct git_var *ptr;
 	for(ptr = git_vars; ptr->read; ptr++) {
-		printf("%s=%s\n", ptr->name, ptr->read());
+		printf("%s=%s\n", ptr->name, ptr->read(0));
 	}
 }
 
@@ -35,7 +35,7 @@ static const char *read_var(const char *var)
 	val = NULL;
 	for(ptr = git_vars; ptr->read; ptr++) {
 		if (strcmp(var, ptr->name) == 0) {
-			val = ptr->read();
+			val = ptr->read(1);
 			break;
 		}
 	}
-- 
cgit v0.10.2-6-g49f6


From d64e6b04291e2313343866a6b206caf13313f1f9 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Sat, 18 Feb 2006 20:51:26 -0800
Subject: Keep Porcelainish from failing by broken ident after making changes.

"empty ident not allowed" error makes commit-tree fail, so we
are already safer in that we would not end up with commit
objects that have bogus names on the author or committer fields.
However, before commit-tree is called there are already changes
made to the index file and the working tree.  The operation can
be resumed after fixing the environment problem, but when this
triggers to a newcomer with unusable gecos, the first question
becomes "what did I lose and how would I recover".

This patch modifies some Porcelainish commands to verify
GIT_COMMITTER_IDENT as soon as we know we are going to make some
commits before doing much damage to prevent confusion.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-am.sh b/git-am.sh
index 98b9215..85ecada 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -1,11 +1,13 @@
 #!/bin/sh
 #
-#
+# Copyright (c) 2005, 2006 Junio C Hamano
 
 USAGE='[--signoff] [--dotest=<dir>] [--utf8] [--binary] [--3way] <mbox>
   or, when resuming [--skip | --resolved]'
 . git-sh-setup
 
+git var GIT_COMMITTER_IDENT >/dev/null || exit
+
 stop_here () {
     echo "$1" >"$dotest/next"
     exit 1
diff --git a/git-applymbox.sh b/git-applymbox.sh
index 61c8c02..5569fdc 100755
--- a/git-applymbox.sh
+++ b/git-applymbox.sh
@@ -21,6 +21,8 @@
 USAGE='[-u] [-k] [-q] [-m] (-c .dotest/<num> | mbox) [signoff]'
 . git-sh-setup
 
+git var GIT_COMMITTER_IDENT >/dev/null || exit
+
 keep_subject= query_apply= continue= utf8= resume=t
 while case "$#" in 0) break ;; esac
 do
diff --git a/git-merge.sh b/git-merge.sh
index 74f0761..2b4a603 100755
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -142,6 +142,8 @@ case "$#,$common,$no_commit" in
 1,*,)
 	# We are not doing octopus, not fast forward, and have only
 	# one common.  See if it is really trivial.
+	git var GIT_COMMITTER_IDENT >/dev/null || exit
+
 	echo "Trying really trivial in-index merge..."
 	git-update-index --refresh 2>/dev/null
 	if git-read-tree --trivial -m -u $common $head "$1" &&
@@ -179,6 +181,9 @@ case "$#,$common,$no_commit" in
 	;;
 esac
 
+# We are going to make a new commit.
+git var GIT_COMMITTER_IDENT >/dev/null || exit
+
 case "$use_strategies" in
 '')
 	case "$#" in
diff --git a/git-resolve.sh b/git-resolve.sh
index 9263070..b53ede8 100755
--- a/git-resolve.sh
+++ b/git-resolve.sh
@@ -50,6 +50,9 @@ case "$common" in
 	;;
 esac
 
+# We are going to make a new commit.
+git var GIT_COMMITTER_IDENT >/dev/null || exit
+
 # Find an optimum merge base if there are more than one candidates.
 LF='
 '
-- 
cgit v0.10.2-6-g49f6


From b2504a0d2ff5a51feb516f7732beb9549b5db454 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@cam.org>
Date: Wed, 22 Feb 2006 16:00:08 -0500
Subject: nicer eye candies for pack-objects

This provides a stable and simpler progress reporting mechanism that
updates progress as often as possible but accurately not updating more
than once a second.  The deltification phase is also made more
interesting to watch (since repacking a big repository and only seeing a
dot appear once every many seconds is rather boring and doesn't provide
much food for anticipation).

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-objects.c b/pack-objects.c
index 0c9f4c9..5e1e14c 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -4,6 +4,7 @@
 #include "pack.h"
 #include "csum-file.h"
 #include <sys/time.h>
+#include <signal.h>
 
 static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 
@@ -661,17 +662,22 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	return 0;
 }
 
+static volatile int progress_update = 0;
+static void progress_interval(int signum)
+{
+	signal(SIGALRM, progress_interval);
+	progress_update = 1;
+}
+
 static void find_deltas(struct object_entry **list, int window, int depth)
 {
 	int i, idx;
 	unsigned int array_size = window * sizeof(struct unpacked);
 	struct unpacked *array = xmalloc(array_size);
-	int eye_candy;
 
 	memset(array, 0, array_size);
 	i = nr_objects;
 	idx = 0;
-	eye_candy = i - (nr_objects / 20);
 
 	while (--i >= 0) {
 		struct object_entry *entry = list[i];
@@ -680,9 +686,10 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 		char type[10];
 		int j;
 
-		if (progress && i <= eye_candy) {
-			eye_candy -= nr_objects / 20;
-			fputc('.', stderr);
+		if (progress_update || i == 0) {
+			fprintf(stderr, "Deltifying (%d %d%%)\r",
+				nr_objects-i, (nr_objects-i) * 100/nr_objects);
+			progress_update = 0;
 		}
 
 		if (entry->delta)
@@ -714,6 +721,9 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 			idx = 0;
 	}
 
+	if (progress)
+		fputc('\n', stderr);
+
 	for (i = 0; i < window; ++i)
 		free(array[i].data);
 	free(array);
@@ -721,17 +731,10 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 
 static void prepare_pack(int window, int depth)
 {
-	if (progress)
-		fprintf(stderr, "Packing %d objects", nr_objects);
 	get_object_details();
-	if (progress)
-		fputc('.', stderr);
-
 	sorted_by_type = create_sorted_list(type_size_sort);
 	if (window && depth)
 		find_deltas(sorted_by_type, window+1, depth);
-	if (progress)
-		fputc('\n', stderr);
 	write_pack_file();
 }
 
@@ -796,10 +799,6 @@ int main(int argc, char **argv)
 	int window = 10, depth = 10, pack_to_stdout = 0;
 	struct object_entry **list;
 	int i;
-	struct timeval prev_tv;
-	int eye_candy = 0;
-	int eye_candy_incr = 500;
-
 
 	setup_git_directory();
 
@@ -856,30 +855,25 @@ int main(int argc, char **argv)
 		usage(pack_usage);
 
 	prepare_packed_git();
+
 	if (progress) {
+		struct itimerval v;
+		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, "Generating pack...\n");
-		gettimeofday(&prev_tv, NULL);
 	}
+
 	while (fgets(line, sizeof(line), stdin) != NULL) {
 		unsigned int hash;
 		char *p;
 		unsigned char sha1[20];
 
-		if (progress && (eye_candy <= nr_objects)) {
+		if (progress_update) {
 			fprintf(stderr, "Counting objects...%d\r", nr_objects);
-			if (eye_candy && (50 <= eye_candy_incr)) {
-				struct timeval tv;
-				int time_diff;
-				gettimeofday(&tv, NULL);
-				time_diff = (tv.tv_sec - prev_tv.tv_sec);
-				time_diff <<= 10;
-				time_diff += (tv.tv_usec - prev_tv.tv_usec);
-				if ((1 << 9) < time_diff)
-					eye_candy_incr += 50;
-				else if (50 < eye_candy_incr)
-					eye_candy_incr -= 50;
-			}
-			eye_candy += eye_candy_incr;
+			progress_update = 0;
 		}
 		if (get_sha1_hex(line, sha1))
 			die("expected sha1, got garbage:\n %s", line);
-- 
cgit v0.10.2-6-g49f6


From 5e8dc750ee56d8c295ecd7478a6bd5d148cb7177 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@cam.org>
Date: Wed, 22 Feb 2006 17:41:32 -0500
Subject: also adds progress when actually writing a pack

If that pack is big, it takes significant time to write and might
benefit from some more eye candies as well.  This is however disabled
when the pack is written to stdout since in that case the output is
usually piped into unpack_objects which already does its own progress
reporting.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-objects.c b/pack-objects.c
index 5e1e14c..dc928b3 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -53,6 +53,7 @@ static int nr_objects = 0, nr_alloc = 0;
 static const char *base_name;
 static unsigned char pack_file_sha1[20];
 static int progress = 1;
+static volatile int progress_update = 0;
 
 /*
  * The object names in objects array are hashed with this hashtable,
@@ -333,8 +334,14 @@ static void write_pack_file(void)
 	hdr.hdr_entries = htonl(nr_objects);
 	sha1write(f, &hdr, sizeof(hdr));
 	offset = sizeof(hdr);
-	for (i = 0; i < nr_objects; i++)
+	for (i = 0; i < nr_objects; i++) {
 		offset = write_one(f, objects + i, offset);
+		if (progress_update) {
+			fprintf(stderr, "Writing (%d %d%%)\r",
+				i+1, (i+1) * 100/nr_objects);
+			progress_update = 0;
+		}
+	}
 
 	sha1close(f, pack_file_sha1, 1);
 }
@@ -662,7 +669,6 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	return 0;
 }
 
-static volatile int progress_update = 0;
 static void progress_interval(int signum)
 {
 	signal(SIGALRM, progress_interval);
@@ -735,7 +741,6 @@ static void prepare_pack(int window, int depth)
 	sorted_by_type = create_sorted_list(type_size_sort);
 	if (window && depth)
 		find_deltas(sorted_by_type, window+1, depth);
-	write_pack_file();
 }
 
 static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout)
@@ -905,6 +910,14 @@ int main(int argc, char **argv)
 		;
 	else {
 		prepare_pack(window, depth);
+		if (progress && pack_to_stdout) {
+			/* the other end usually displays progress itself */
+			struct itimerval v = {{0,},};
+			setitimer(ITIMER_REAL, &v, NULL);
+			signal(SIGALRM, SIG_IGN );
+			progress_update = 0;
+		}
+		write_pack_file();
 		if (!pack_to_stdout) {
 			write_index_file();
 			puts(sha1_to_hex(object_list_sha1));
-- 
cgit v0.10.2-6-g49f6


From 183bdb2cccff792f11fd9e825df67af446aff171 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Wed, 22 Feb 2006 16:02:59 -0800
Subject: pack-objects eye-candy: finishing touches.

This updates the progress output to match "every one second or
every percent whichever comes early" used by unpack-objects, as
discussed on the list.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-objects.c b/pack-objects.c
index dc928b3..8f352aa 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -324,11 +324,19 @@ static void write_pack_file(void)
 	struct sha1file *f;
 	unsigned long offset;
 	struct pack_header hdr;
+	unsigned last_percent = 999;
+	int do_progress = 0;
 
 	if (!base_name)
 		f = sha1fd(1, "<stdout>");
-	else
-		f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "pack");
+	else {
+		f = sha1create("%s-%s.%s", base_name,
+			       sha1_to_hex(object_list_sha1), "pack");
+		do_progress = progress;
+	}
+	if (do_progress)
+		fprintf(stderr, "Writing %d objects.\n", nr_objects);
+
 	hdr.hdr_signature = htonl(PACK_SIGNATURE);
 	hdr.hdr_version = htonl(PACK_VERSION);
 	hdr.hdr_entries = htonl(nr_objects);
@@ -336,12 +344,18 @@ static void write_pack_file(void)
 	offset = sizeof(hdr);
 	for (i = 0; i < nr_objects; i++) {
 		offset = write_one(f, objects + i, offset);
-		if (progress_update) {
-			fprintf(stderr, "Writing (%d %d%%)\r",
-				i+1, (i+1) * 100/nr_objects);
-			progress_update = 0;
+		if (do_progress) {
+			unsigned percent = written * 100 / nr_objects;
+			if (progress_update || percent != last_percent) {
+				fprintf(stderr, "%4u%% (%u/%u) done\r",
+					percent, written, nr_objects);
+				progress_update = 0;
+				last_percent = percent;
+			}
 		}
 	}
+	if (do_progress)
+		fputc('\n', stderr);
 
 	sha1close(f, pack_file_sha1, 1);
 }
@@ -680,10 +694,14 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 	int i, idx;
 	unsigned int array_size = window * sizeof(struct unpacked);
 	struct unpacked *array = xmalloc(array_size);
+	unsigned processed = 0;
+	unsigned last_percent = 999;
 
 	memset(array, 0, array_size);
 	i = nr_objects;
 	idx = 0;
+	if (progress)
+		fprintf(stderr, "Deltifying %d objects.\n", nr_objects);
 
 	while (--i >= 0) {
 		struct object_entry *entry = list[i];
@@ -692,10 +710,15 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 		char type[10];
 		int j;
 
-		if (progress_update || i == 0) {
-			fprintf(stderr, "Deltifying (%d %d%%)\r",
-				nr_objects-i, (nr_objects-i) * 100/nr_objects);
-			progress_update = 0;
+		processed++;
+		if (progress) {
+			unsigned percent = processed * 100 / nr_objects;
+			if (percent != last_percent || progress_update) {
+				fprintf(stderr, "%4u%% (%u/%u) done\r",
+					percent, processed, nr_objects);
+				progress_update = 0;
+				last_percent = percent;
+			}
 		}
 
 		if (entry->delta)
-- 
cgit v0.10.2-6-g49f6


From 6dc78e696b8597204b903073da932fc5ed0f419e Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Wed, 22 Feb 2006 13:10:37 -0800
Subject: git-fetch: follow tag only when tracking remote branch.

Unless --no-tags flag was given, git-fetch tried to always
follow remote tags that point at the commits we picked up.

It is not very useful to pick up tags from remote unless storing
the fetched branch head in a local tracking branch.  This is
especially true if the fetch is done to merge the remote branch
into our current branch as one-shot basis (i.e. "please pull"),
and is even harmful if the remote repository has many irrelevant
tags.

This proposed update disables the automated tag following unless
we are storing the a fetched branch head in a local tracking
branch.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-fetch.sh b/git-fetch.sh
index b4325d9..fcc24f8 100755
--- a/git-fetch.sh
+++ b/git-fetch.sh
@@ -368,20 +368,25 @@ fetch_main "$reflist"
 # automated tag following
 case "$no_tags$tags" in
 '')
-	taglist=$(IFS=" " &&
-	git-ls-remote $upload_pack --tags "$remote" |
-	sed -ne 's|^\([0-9a-f]*\)[ 	]\(refs/tags/.*\)^{}$|\1 \2|p' |
-	while read sha1 name
-	do
-		test -f "$GIT_DIR/$name" && continue
-	  	git-check-ref-format "$name" || {
-			echo >&2 "warning: tag ${name} ignored"
-			continue
-		}
-		git-cat-file -t "$sha1" >/dev/null 2>&1 || continue
-		echo >&2 "Auto-following $name"
-		echo ".${name}:${name}"
-	done)
+	case "$reflist" in
+	*:refs/*)
+		# effective only when we are following remote branch
+		# using local tracking branch.
+		taglist=$(IFS=" " &&
+		git-ls-remote $upload_pack --tags "$remote" |
+		sed -ne 's|^\([0-9a-f]*\)[ 	]\(refs/tags/.*\)^{}$|\1 \2|p' |
+		while read sha1 name
+		do
+			test -f "$GIT_DIR/$name" && continue
+			git-check-ref-format "$name" || {
+				echo >&2 "warning: tag ${name} ignored"
+				continue
+			}
+			git-cat-file -t "$sha1" >/dev/null 2>&1 || continue
+			echo >&2 "Auto-following $name"
+			echo ".${name}:${name}"
+		done)
+	esac
 	case "$taglist" in
 	'') ;;
 	?*)
-- 
cgit v0.10.2-6-g49f6