Revert "pack-objects: use of version 3 delta is now optional."

This reverts commit 394737eb42.

Saving a few bytes per every 64kB of delta copied is not worth,
when compared with the cost of backward compatibility worries.

builtin-pack-objects.c

@@ -456,7 +456,7 @@ static void write_pack_file(void)
 		fprintf(stderr, "Writing %d objects.\n", nr_result);
 
 	hdr.hdr_signature = htonl(PACK_SIGNATURE);
-	hdr.hdr_version = htonl(delta_version);
+	hdr.hdr_version = htonl(PACK_VERSION);
 	hdr.hdr_entries = htonl(nr_result);
 	sha1write(f, &hdr, sizeof(hdr));
 	offset = sizeof(hdr);
@@ -914,15 +914,12 @@ static void check_object(struct object_entry *entry)
 		/* 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.
-		 *
-		 * Also make sure that we do not reuse delta from an existing
-		 * pack that uses higher delta version than allowed.
 		 */
 		if (!no_reuse_delta &&
 		    entry->in_pack_type == OBJ_DELTA &&
 		    (base_entry = locate_object_entry(base)) &&
-		    (!base_entry->preferred_base) &&
-		    entry->in_pack->pack_version <= delta_version) {
+		    (!base_entry->preferred_base)) {
+
 			/* Depth value does not matter - find_deltas()
 			 * will never consider reused delta as the
 			 * base object to deltify other objects
@@ -1104,7 +1101,6 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
 	 * on an earlier try, but only when reusing delta data.
 	 */
 	if (!no_reuse_delta && trg_entry->in_pack &&
-	    trg_entry->in_pack->pack_version <= delta_version &&
 	    trg_entry->in_pack == src_entry->in_pack)
 		return 0;
 
@@ -1330,15 +1326,10 @@ static void setup_progress_signal(void)
 
 static int git_pack_config(const char *k, const char *v)
 {
-	if (!strcmp(k, "pack.window")) {
+	if(!strcmp(k, "pack.window")) {
 		window = git_config_int(k, v);
 		return 0;
 	}
-	if (!strcmp(k, "pack.deltaversion")) {
-		delta_version = git_config_int(k, v);
-		if (!pack_version_ok(htonl(delta_version)))
-			die("value %s for '%s' not allowed", v, k);
-	}
 	return git_default_config(k, v);
 }
 

cache.h

@@ -337,7 +337,6 @@ extern struct packed_git {
 	unsigned int pack_last_used;
 	unsigned int pack_use_cnt;
 	int pack_local;
-	int pack_version;
 	unsigned char sha1[20];
 	/* something like ".git/objects/pack/xxxxx.pack" */
 	char pack_name[FLEX_ARRAY]; /* more */

delta.h

@@ -1,8 +1,6 @@
 #ifndef DELTA_H
 #define DELTA_H
 
-extern int delta_version;
-
 /* opaque object for delta index */
 struct delta_index;
 

diff-delta.c

@@ -253,13 +253,10 @@ create_delta(const struct delta_index *index,
 	int inscnt;
 	const unsigned char *ref_data, *ref_top, *data, *top;
 	unsigned char *out;
-	unsigned int ref_size_limit;
 
 	if (!trg_buf || !trg_size)
 		return NULL;
 
-	ref_size_limit = (delta_version > 2) ? 0xffffff : 0x10000;
-
 	outpos = 0;
 	outsize = 8192;
 	if (max_size && outsize >= max_size)
@@ -311,8 +308,8 @@ create_delta(const struct delta_index *index,
 				continue;
 			if (ref_size > top - src)
 				ref_size = top - src;
-			if (ref_size > ref_size_limit)
-				ref_size = ref_size_limit;
+			if (ref_size > 0x10000)
+				ref_size = 0x10000;
 			if (ref_size <= msize)
 				break;
 			while (ref_size-- && *src++ == *ref)
@@ -321,8 +318,6 @@ create_delta(const struct delta_index *index,
 				/* this is our best match so far */
 				msize = ref - entry->ptr;
 				moff = entry->ptr - ref_data;
-				if (delta_version > 2 && msize >= 0x10000)
-					break; /* this is good enough */
 			}
 		}
 
@@ -386,12 +381,6 @@ create_delta(const struct delta_index *index,
 			if (msize & 0xff) { out[outpos++] = msize; i |= 0x10; }
 			msize >>= 8;
 			if (msize & 0xff) { out[outpos++] = msize; i |= 0x20; }
-			if (delta_version > 2) {
-				msize >>= 8;
-				if (msize & 0xff) {
-					out[outpos++] = msize; i |= 0x40;
-				}
-			}
 
 			*op = i;
 		}

environment.c

@@ -8,7 +8,6 @@
  * are.
  */
 #include "cache.h"
-#include "pack.h"
 
 char git_default_email[MAX_GITNAME];
 char git_default_name[MAX_GITNAME];
@@ -26,8 +25,6 @@ const char *apply_default_whitespace;
 int zlib_compression_level = Z_DEFAULT_COMPRESSION;
 int pager_in_use;
 int pager_use_color = 1;
-/* by default we allow 2 but up to PACK_VERSION is allowed */
-int delta_version = 2;
 
 static const char *git_dir;
 static char *git_object_dir, *git_index_file, *git_refs_dir, *git_graft_file;

sha1_file.c

@@ -527,7 +527,6 @@ int use_packed_git(struct packed_git *p)
 			    p->pack_size - 20)) {
 			die("packfile %s does not match index.", p->pack_name);
 		}
-		p->pack_version = ntohl(hdr->hdr_version);
 	}
 	p->pack_last_used = pack_used_ctr++;
 	p->pack_use_cnt++;