Merge branch 'ks/pack-objects-bitmap'

Some codepaths in "git pack-objects" were not ready to use an
existing pack bitmap; now they are and as the result they have
become faster.

* ks/pack-objects-bitmap:
  pack-objects: use reachability bitmap index when generating non-stdout pack
  pack-objects: respect --local/--honor-pack-keep/--incremental when bitmap is in use

3 files changed, 205 insertions, 41 deletions

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 0954375..166e52c 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -67,7 +67,8 @@ static struct packed_git *reuse_packfile;
 static uint32_t reuse_packfile_objects;
 static off_t reuse_packfile_offset;
 
-static int use_bitmap_index = 1;
+static int use_bitmap_index_default = 1;
+static int use_bitmap_index = -1;
 static int write_bitmap_index;
 static uint16_t write_bitmap_options;
 
@@ -945,13 +946,48 @@ static int have_duplicate_entry(const unsigned char *sha1,
 	return 1;
 }
 
+static int want_found_object(int exclude, struct packed_git *p)
+{
+	if (exclude)
+		return 1;
+	if (incremental)
+		return 0;
+
+	/*
+	 * When asked to do --local (do not include an object that appears in a
+	 * pack we borrow from elsewhere) or --honor-pack-keep (do not include
+	 * an object that appears in a pack marked with .keep), finding a pack
+	 * that matches the criteria is sufficient for us to decide to omit it.
+	 * However, even if this pack does not satisfy the criteria, we need to
+	 * make sure no copy of this object appears in _any_ pack that makes us
+	 * to omit the object, so we need to check all the packs.
+	 *
+	 * We can however first check whether these options can possible matter;
+	 * if they do not matter we know we want the object in generated pack.
+	 * Otherwise, we signal "-1" at the end to tell the caller that we do
+	 * not know either way, and it needs to check more packs.
+	 */
+	if (!ignore_packed_keep &&
+	    (!local || !have_non_local_packs))
+		return 1;
+
+	if (local && !p->pack_local)
+		return 0;
+	if (ignore_packed_keep && p->pack_local && p->pack_keep)
+		return 0;
+
+	/* we don't know yet; keep looking for more packs */
+	return -1;
+}
+
 /*
  * Check whether we want the object in the pack (e.g., we do not want
  * objects found in non-local stores if the "--local" option was used).
  *
- * As a side effect of this check, we will find the packed version of this
- * object, if any. We therefore pass out the pack information to avoid having
- * to look it up again later.
+ * If the caller already knows an existing pack it wants to take the object
+ * from, that is passed in *found_pack and *found_offset; otherwise this
+ * function finds if there is any pack that has the object and returns the pack
+ * and its offset in these variables.
  */
 static int want_object_in_pack(const unsigned char *sha1,
 			       int exclude,
@@ -959,15 +995,30 @@ static int want_object_in_pack(const unsigned char *sha1,
 			       off_t *found_offset)
 {
 	struct packed_git *p;
+	int want;
 
 	if (!exclude && local && has_loose_object_nonlocal(sha1))
 		return 0;
 
-	*found_pack = NULL;
-	*found_offset = 0;
+	/*
+	 * If we already know the pack object lives in, start checks from that
+	 * pack - in the usual case when neither --local was given nor .keep files
+	 * are present we will determine the answer right now.
+	 */
+	if (*found_pack) {
+		want = want_found_object(exclude, *found_pack);
+		if (want != -1)
+			return want;
+	}
 
 	for (p = packed_git; p; p = p->next) {
-		off_t offset = find_pack_entry_one(sha1, p);
+		off_t offset;
+
+		if (p == *found_pack)
+			offset = *found_offset;
+		else
+			offset = find_pack_entry_one(sha1, p);
+
 		if (offset) {
 			if (!*found_pack) {
 				if (!is_pack_valid(p))
@@ -975,31 +1026,9 @@ static int want_object_in_pack(const unsigned char *sha1,
 				*found_offset = offset;
 				*found_pack = p;
 			}
-			if (exclude)
-				return 1;
-			if (incremental)
-				return 0;
-
-			/*
-			 * When asked to do --local (do not include an
-			 * object that appears in a pack we borrow
-			 * from elsewhere) or --honor-pack-keep (do not
-			 * include an object that appears in a pack marked
-			 * with .keep), we need to make sure no copy of this
-			 * object come from in _any_ pack that causes us to
-			 * omit it, and need to complete this loop.  When
-			 * neither option is in effect, we know the object
-			 * we just found is going to be packed, so break
-			 * out of the loop to return 1 now.
-			 */
-			if (!ignore_packed_keep &&
-			    (!local || !have_non_local_packs))
-				break;
-
-			if (local && !p->pack_local)
-				return 0;
-			if (ignore_packed_keep && p->pack_local && p->pack_keep)
-				return 0;
+			want = want_found_object(exclude, p);
+			if (want != -1)
+				return want;
 		}
 	}
 
@@ -1040,8 +1069,8 @@ static const char no_closure_warning[] = N_(
 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 			    const char *name, int exclude)
 {
-	struct packed_git *found_pack;
-	off_t found_offset;
+	struct packed_git *found_pack = NULL;
+	off_t found_offset = 0;
 	uint32_t index_pos;
 
 	if (have_duplicate_entry(sha1, exclude, &index_pos))
@@ -1074,6 +1103,9 @@ static int add_object_entry_from_bitmap(const unsigned char *sha1,
 	if (have_duplicate_entry(sha1, 0, &index_pos))
 		return 0;
 
+	if (!want_object_in_pack(sha1, 0, &pack, &offset))
+		return 0;
+
 	create_object_entry(sha1, type, name_hash, 0, 0, index_pos, pack, offset);
 
 	display_progress(progress_state, nr_result);
@@ -2273,7 +2305,7 @@ static int git_pack_config(const char *k, const char *v, void *cb)
 			write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
 	}
 	if (!strcmp(k, "pack.usebitmaps")) {
-		use_bitmap_index = git_config_bool(k, v);
+		use_bitmap_index_default = git_config_bool(k, v);
 		return 0;
 	}
 	if (!strcmp(k, "pack.threads")) {
@@ -2522,13 +2554,13 @@ static void loosen_unused_packed_objects(struct rev_info *revs)
 }
 
 /*
- * This tracks any options which a reader of the pack might
- * not understand, and which would therefore prevent blind reuse
- * of what we have on disk.
+ * This tracks any options which pack-reuse code expects to be on, or which a
+ * reader of the pack might not understand, and which would therefore prevent
+ * blind reuse of what we have on disk.
  */
 static int pack_options_allow_reuse(void)
 {
-	return allow_ofs_delta;
+	return pack_to_stdout && allow_ofs_delta;
 }
 
 static int get_object_list_from_bitmap(struct rev_info *revs)
@@ -2821,7 +2853,23 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	if (!rev_list_all || !rev_list_reflog || !rev_list_index)
 		unpack_unreachable_expiration = 0;
 
-	if (!use_internal_rev_list || !pack_to_stdout || is_repository_shallow())
+	/*
+	 * "soft" reasons not to use bitmaps - for on-disk repack by default we want
+	 *
+	 * - to produce good pack (with bitmap index not-yet-packed objects are
+	 *   packed in suboptimal order).
+	 *
+	 * - to use more robust pack-generation codepath (avoiding possible
+	 *   bugs in bitmap code and possible bitmap index corruption).
+	 */
+	if (!pack_to_stdout)
+		use_bitmap_index_default = 0;
+
+	if (use_bitmap_index < 0)
+		use_bitmap_index = use_bitmap_index_default;
+
+	/* "hard" reasons not to use bitmaps; these just won't work at all */
+	if (!use_internal_rev_list || (!pack_to_stdout && write_bitmap_index) || is_repository_shallow())
 		use_bitmap_index = 0;
 
 	if (pack_to_stdout || !rev_list_all)
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index de2a224..bb91dbb 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -32,6 +32,14 @@ test_perf 'simulated fetch' '
 	} | git pack-objects --revs --stdout >/dev/null
 '
 
+test_perf 'pack to file' '
+	git pack-objects --all pack1 </dev/null >/dev/null
+'
+
+test_perf 'pack to file (bitmap)' '
+	git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
+'
+
 test_expect_success 'create partial bitmap state' '
 	# pick a commit to represent the repo tip in the past
 	cutoff=$(git rev-list HEAD~100 -1) &&
@@ -53,8 +61,12 @@ test_expect_success 'create partial bitmap state' '
 	git update-ref HEAD $orig_tip
 '
 
-test_perf 'partial bitmap' '
+test_perf 'clone (partial bitmap)' '
 	git pack-objects --stdout --all </dev/null >/dev/null
 '
 
+test_perf 'pack to file (partial bitmap)' '
+	git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
+'
+
 test_done
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index 1e376ea..b4c7a6f 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -7,6 +7,18 @@ objpath () {
 	echo ".git/objects/$(echo "$1" | sed -e 's|\(..\)|\1/|')"
 }
 
+# show objects present in pack ($1 should be associated *.idx)
+list_packed_objects () {
+	git show-index <"$1" | cut -d' ' -f2
+}
+
+# has_any pattern-file content-file
+# tests whether content-file has any entry from pattern-file with entries being
+# whole lines.
+has_any () {
+	grep -Ff "$1" "$2"
+}
+
 test_expect_success 'setup repo with moderate-sized history' '
 	for i in $(test_seq 1 10); do
 		test_commit $i
@@ -16,6 +28,7 @@ test_expect_success 'setup repo with moderate-sized history' '
 		test_commit side-$i
 	done &&
 	git checkout master &&
+	bitmaptip=$(git rev-parse master) &&
 	blob=$(echo tagged-blob | git hash-object -w --stdin) &&
 	git tag tagged-blob $blob &&
 	git config repack.writebitmaps true &&
@@ -118,6 +131,83 @@ test_expect_success 'incremental repack can disable bitmaps' '
 	git repack -d --no-write-bitmap-index
 '
 
+test_expect_success 'pack-objects respects --local (non-local loose)' '
+	git init --bare alt.git &&
+	echo $(pwd)/alt.git/objects >.git/objects/info/alternates &&
+	echo content1 >file1 &&
+	# non-local loose object which is not present in bitmapped pack
+	altblob=$(GIT_DIR=alt.git git hash-object -w file1) &&
+	# non-local loose object which is also present in bitmapped pack
+	git cat-file blob $blob | GIT_DIR=alt.git git hash-object -w --stdin &&
+	git add file1 &&
+	test_tick &&
+	git commit -m commit_file1 &&
+	echo HEAD | git pack-objects --local --stdout --revs >1.pack &&
+	git index-pack 1.pack &&
+	list_packed_objects 1.idx >1.objects &&
+	printf "%s\n" "$altblob" "$blob" >nonlocal-loose &&
+	! has_any nonlocal-loose 1.objects
+'
+
+test_expect_success 'pack-objects respects --honor-pack-keep (local non-bitmapped pack)' '
+	echo content2 >file2 &&
+	blob2=$(git hash-object -w file2) &&
+	git add file2 &&
+	test_tick &&
+	git commit -m commit_file2 &&
+	printf "%s\n" "$blob2" "$bitmaptip" >keepobjects &&
+	pack2=$(git pack-objects pack2 <keepobjects) &&
+	mv pack2-$pack2.* .git/objects/pack/ &&
+	>.git/objects/pack/pack2-$pack2.keep &&
+	rm $(objpath $blob2) &&
+	echo HEAD | git pack-objects --honor-pack-keep --stdout --revs >2a.pack &&
+	git index-pack 2a.pack &&
+	list_packed_objects 2a.idx >2a.objects &&
+	! has_any keepobjects 2a.objects
+'
+
+test_expect_success 'pack-objects respects --local (non-local pack)' '
+	mv .git/objects/pack/pack2-$pack2.* alt.git/objects/pack/ &&
+	echo HEAD | git pack-objects --local --stdout --revs >2b.pack &&
+	git index-pack 2b.pack &&
+	list_packed_objects 2b.idx >2b.objects &&
+	! has_any keepobjects 2b.objects
+'
+
+test_expect_success 'pack-objects respects --honor-pack-keep (local bitmapped pack)' '
+	ls .git/objects/pack/ | grep bitmap >output &&
+	test_line_count = 1 output &&
+	packbitmap=$(basename $(cat output) .bitmap) &&
+	list_packed_objects .git/objects/pack/$packbitmap.idx >packbitmap.objects &&
+	test_when_finished "rm -f .git/objects/pack/$packbitmap.keep" &&
+	>.git/objects/pack/$packbitmap.keep &&
+	echo HEAD | git pack-objects --honor-pack-keep --stdout --revs >3a.pack &&
+	git index-pack 3a.pack &&
+	list_packed_objects 3a.idx >3a.objects &&
+	! has_any packbitmap.objects 3a.objects
+'
+
+test_expect_success 'pack-objects respects --local (non-local bitmapped pack)' '
+	mv .git/objects/pack/$packbitmap.* alt.git/objects/pack/ &&
+	test_when_finished "mv alt.git/objects/pack/$packbitmap.* .git/objects/pack/" &&
+	echo HEAD | git pack-objects --local --stdout --revs >3b.pack &&
+	git index-pack 3b.pack &&
+	list_packed_objects 3b.idx >3b.objects &&
+	! has_any packbitmap.objects 3b.objects
+'
+
+test_expect_success 'pack-objects to file can use bitmap' '
+	# make sure we still have 1 bitmap index from previous tests
+	ls .git/objects/pack/ | grep bitmap >output &&
+	test_line_count = 1 output &&
+	# verify equivalent packs are generated with/without using bitmap index
+	packasha1=$(git pack-objects --no-use-bitmap-index --all packa </dev/null) &&
+	packbsha1=$(git pack-objects --use-bitmap-index --all packb </dev/null) &&
+	list_packed_objects <packa-$packasha1.idx >packa.objects &&
+	list_packed_objects <packb-$packbsha1.idx >packb.objects &&
+	test_cmp packa.objects packb.objects
+'
+
 test_expect_success 'full repack, reusing previous bitmaps' '
 	git repack -ad &&
 	ls .git/objects/pack/ | grep bitmap >output &&
@@ -143,6 +233,20 @@ test_expect_success 'create objects for missing-HAVE tests' '
 	EOF
 '
 
+test_expect_success 'pack-objects respects --incremental' '
+	cat >revs2 <<-EOF &&
+	HEAD
+	$commit
+	EOF
+	git pack-objects --incremental --stdout --revs <revs2 >4.pack &&
+	git index-pack 4.pack &&
+	list_packed_objects 4.idx >4.objects &&
+	test_line_count = 4 4.objects &&
+	git rev-list --objects $commit >revlist &&
+	cut -d" " -f1 revlist |sort >objects &&
+	test_cmp 4.objects objects
+'
+
 test_expect_success 'pack with missing blob' '
 	rm $(objpath $blob) &&
 	git pack-objects --stdout --revs <revs >/dev/null