t3302-notes-index-expensive: Speed up create_repo()

Creating repos with 10/100/1000/10000 commits and notes takes a lot of time.
However, using git-fast-import to do the job is a lot more efficient than
using plumbing commands to do the same.

This patch decreases the overall run-time of this test on my machine from
~3 to ~1 minutes.

Signed-off-by: Johan Herland <johan@herland.net>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3302-notes-index-expensive.sh

@@ -16,30 +16,50 @@ test -z "$GIT_NOTES_TIMING_TESTS" && {
 create_repo () {
 	number_of_commits=$1
 	nr=0
-	parent=
 	test -d .git || {
 	git init &&
-	tree=$(git write-tree) &&
-	while [ $nr -lt $number_of_commits ]; do
+	(
+		while [ $nr -lt $number_of_commits ]; do
+			nr=$(($nr+1))
+			mark=$(($nr+$nr))
+			notemark=$(($mark+1))
+			test_tick &&
+			cat <<INPUT_END &&
+commit refs/heads/master
+mark :$mark
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+commit #$nr
+COMMIT
+
+M 644 inline file
+data <<EOF
+file in commit #$nr
+EOF
+
+blob
+mark :$notemark
+data <<EOF
+note for commit #$nr
+EOF
+
+INPUT_END
+
+			echo "N :$notemark :$mark" >> note_commit
+		done &&
 		test_tick &&
-		commit=$(echo $nr | git commit-tree $tree $parent) ||
-			return
-		parent="-p $commit"
-		nr=$(($nr+1))
-	done &&
-	git update-ref refs/heads/master $commit &&
-	{
-		GIT_INDEX_FILE=.git/temp; export GIT_INDEX_FILE;
-		git rev-list HEAD | cat -n | sed "s/^[ 	][ 	]*/ /g" |
-		while read nr sha1; do
-			blob=$(echo note $nr | git hash-object -w --stdin) &&
-			echo $sha1 | sed "s/^/0644 $blob 0	/"
-		done | git update-index --index-info &&
-		tree=$(git write-tree) &&
-		test_tick &&
-		commit=$(echo notes | git commit-tree $tree) &&
-		git update-ref refs/notes/commits $commit
-	} &&
+		cat <<INPUT_END &&
+commit refs/notes/commits
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+notes
+COMMIT
+
+INPUT_END
+
+		cat note_commit
+	) |
+	git fast-import --quiet &&
 	git config core.notesRef refs/notes/commits
 	}
 }
@@ -48,13 +68,13 @@ test_notes () {
 	count=$1 &&
 	git config core.notesRef refs/notes/commits &&
 	git log | grep "^    " > output &&
-	i=1 &&
-	while [ $i -le $count ]; do
-		echo "    $(($count-$i))" &&
-		echo "    note $i" &&
-		i=$(($i+1));
+	i=$count &&
+	while [ $i -gt 0 ]; do
+		echo "    commit #$i" &&
+		echo "    note for commit #$i" &&
+		i=$(($i-1));
 	done > expect &&
-	git diff expect output
+	test_cmp expect output
 }
 
 cat > time_notes << \EOF