repack: introduce repack.writeBitmaps config option

We currently have pack.writeBitmaps, which originally
operated at the pack-objects level. This should really have
been a repack.* option from day one. Let's give it the more
sensible name, but keep the old version as a deprecated
synonym.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

Documentation/config.txt

@@ -1865,12 +1865,7 @@ pack.useBitmaps::
 	you are debugging pack bitmaps.
 
 pack.writebitmaps::
-	When true, git will write a bitmap index when packing all
-	objects to disk (e.g., when `git repack -a` is run).  This
-	index can speed up the "counting objects" phase of subsequent
-	packs created for clones and fetches, at the cost of some disk
-	space and extra time spent on the initial repack.  Defaults to
-	false.
+	This is a deprecated synonym for `repack.writeBitmaps`.
 
 pack.writeBitmapHashCache::
 	When true, git will include a "hash cache" section in the bitmap
@@ -2133,7 +2128,15 @@ repack.packKeptObjects::
 	`--pack-kept-objects` was passed. See linkgit:git-repack[1] for
 	details. Defaults to `false` normally, but `true` if a bitmap
 	index is being written (either via `--write-bitmap-index` or
-	`pack.writeBitmaps`).
+	`repack.writeBitmaps`).
+
+repack.writeBitmaps::
+	When true, git will write a bitmap index when packing all
+	objects to disk (e.g., when `git repack -a` is run).  This
+	index can speed up the "counting objects" phase of subsequent
+	packs created for clones and fetches, at the cost of some disk
+	space and extra time spent on the initial repack.  Defaults to
+	false.
 
 rerere.autoupdate::
 	When set to true, `git-rerere` updates the index with the

builtin/repack.c

@@ -28,7 +28,8 @@ static int repack_config(const char *var, const char *value, void *cb)
 		pack_kept_objects = git_config_bool(var, value);
 		return 0;
 	}
-	if (!strcmp(var, "pack.writebitmaps")) {
+	if (!strcmp(var, "repack.writebitmaps") ||
+	    !strcmp(var, "pack.writebitmaps")) {
 		write_bitmaps = git_config_bool(var, value);
 		return 0;
 	}

t/perf/p5310-pack-bitmaps.sh

@@ -8,6 +8,9 @@ test_perf_large_repo
 # note that we do everything through config,
 # since we want to be able to compare bitmap-aware
 # git versus non-bitmap git
+#
+# We intentionally use the deprecated pack.writebitmaps
+# config so that we can test against older versions of git.
 test_expect_success 'setup bitmap config' '
 	git config pack.writebitmaps true &&
 	git config pack.writebitmaphashcache true

t/t5310-pack-bitmaps.sh

@@ -14,7 +14,7 @@ test_expect_success 'setup repo with moderate-sized history' '
 	git checkout master &&
 	blob=$(echo tagged-blob | git hash-object -w --stdin) &&
 	git tag tagged-blob $blob &&
-	git config pack.writebitmaps true &&
+	git config repack.writebitmaps true &&
 	git config pack.writebitmaphashcache true
 '
 

t/t7700-repack.sh

@@ -53,7 +53,7 @@ test_expect_success 'writing bitmaps via command-line can duplicate .keep object
 
 test_expect_success 'writing bitmaps via config can duplicate .keep objects' '
 	# build on $objsha1, $packsha1, and .keep state from previous
-	git -c pack.writebitmaps=true repack -Adl &&
+	git -c repack.writebitmaps=true repack -Adl &&
 	test_when_finished "found_duplicate_object=" &&
 	for p in .git/objects/pack/*.idx; do
 		idx=$(basename $p)