pack-bitmap-write: learn pack.writeBitmapLookupTable and add tests

Teach Git to provide a way for users to enable/disable bitmap lookup
table extension by providing a config option named 'writeBitmapLookupTable'.
Default is false.

Also add test to verify writting of lookup table.

Mentored-by: Taylor Blau <me@ttaylorr.com>
Co-Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Co-Authored-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 35 insertions, 18 deletions

diff --git a/t/t5311-pack-bitmaps-shallow.sh b/t/t5311-pack-bitmaps-shallow.sh
index 872a95df33..9dae60f73e 100755
--- a/t/t5311-pack-bitmaps-shallow.sh
+++ b/t/t5311-pack-bitmaps-shallow.sh
@@ -17,23 +17,40 @@ test_description='check bitmap operation with shallow repositories'
 # the tree for A. But in a shallow one, we've grafted away
 # A, and fetching A to B requires that the other side send
 # us the tree for file=1.
-test_expect_success 'setup shallow repo' '
-	echo 1 >file &&
-	git add file &&
-	git commit -m orig &&
-	echo 2 >file &&
-	git commit -a -m update &&
-	git clone --no-local --bare --depth=1 . shallow.git &&
-	echo 1 >file &&
-	git commit -a -m repeat
-'
-
-test_expect_success 'turn on bitmaps in the parent' '
-	git repack -adb
-'
-
-test_expect_success 'shallow fetch from bitmapped repo' '
-	(cd shallow.git && git fetch)
-'
+test_shallow_bitmaps () {
+	writeLookupTable=false
+
+	for i in "$@"
+	do
+		case $i in
+		"pack.writeBitmapLookupTable") writeLookupTable=true;;
+		esac
+	done
+
+	test_expect_success 'setup shallow repo' '
+		rm -rf * .git &&
+		git init &&
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+		echo 1 >file &&
+		git add file &&
+		git commit -m orig &&
+		echo 2 >file &&
+		git commit -a -m update &&
+		git clone --no-local --bare --depth=1 . shallow.git &&
+		echo 1 >file &&
+		git commit -a -m repeat
+	'
+
+	test_expect_success 'turn on bitmaps in the parent' '
+		git repack -adb
+	'
+
+	test_expect_success 'shallow fetch from bitmapped repo' '
+		(cd shallow.git && git fetch)
+	'
+}
+
+test_shallow_bitmaps
+test_shallow_bitmaps "pack.writeBitmapLookupTable"
 
 test_done