merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 82 insertions, 35 deletions

diff --git a/third_party/git/t/t3305-notes-fanout.sh b/third_party/git/t/t3305-notes-fanout.sh
index 54460beec469..94c1b02251c2 100755
--- a/third_party/git/t/t3305-notes-fanout.sh
+++ b/third_party/git/t/t3305-notes-fanout.sh
@@ -4,6 +4,38 @@ test_description='Test that adding/removing many notes triggers automatic fanout
 
 . ./test-lib.sh
 
+path_has_fanout() {
+	path=$1 &&
+	fanout=$2 &&
+	after_last_slash=$(($(test_oid hexsz) - $fanout * 2)) &&
+	echo $path | grep -q "^\([0-9a-f]\{2\}/\)\{$fanout\}[0-9a-f]\{$after_last_slash\}$"
+}
+
+touched_one_note_with_fanout() {
+	notes_commit=$1 &&
+	modification=$2 &&  # 'A' for addition, 'D' for deletion
+	fanout=$3 &&
+	diff=$(git diff-tree --no-commit-id --name-status --root -r $notes_commit) &&
+	path=$(echo $diff | sed -e "s/^$modification[\t ]//") &&
+	path_has_fanout "$path" $fanout;
+}
+
+all_notes_have_fanout() {
+	notes_commit=$1 &&
+	fanout=$2 &&
+	git ls-tree -r --name-only $notes_commit 2>/dev/null |
+	while read path
+	do
+		path_has_fanout $path $fanout || return 1
+	done
+}
+
+test_expect_success 'tweak test environment' '
+	git checkout -b nondeterminism &&
+	test_commit A &&
+	git checkout --orphan with_notes;
+'
+
 test_expect_success 'creating many notes with git-notes' '
 	num_notes=300 &&
 	i=0 &&
@@ -20,7 +52,7 @@ test_expect_success 'creating many notes with git-notes' '
 
 test_expect_success 'many notes created correctly with git-notes' '
 	git log | grep "^    " > output &&
-	i=300 &&
+	i=$num_notes &&
 	while test $i -gt 0
 	do
 		echo "    commit #$i" &&
@@ -30,39 +62,46 @@ test_expect_success 'many notes created correctly with git-notes' '
 	test_cmp expect output
 '
 
-test_expect_success 'many notes created with git-notes triggers fanout' '
-	# Expect entire notes tree to have a fanout == 1
-	git ls-tree -r --name-only refs/notes/commits |
-	while read path
+test_expect_success 'stable fanout 0 is followed by stable fanout 1' '
+	i=$num_notes &&
+	fanout=0 &&
+	while test $i -gt 0
 	do
-		case "$path" in
-		??/??????????????????????????????????????)
-			: true
-			;;
-		*)
-			echo "Invalid path \"$path\"" &&
-			return 1
-			;;
-		esac
-	done
+		i=$(($i - 1)) &&
+		if touched_one_note_with_fanout refs/notes/commits~$i A $fanout
+		then
+			continue
+		elif test $fanout -eq 0
+		then
+			fanout=1 &&
+			if all_notes_have_fanout refs/notes/commits~$i $fanout
+			then
+				echo "Fanout 0 -> 1 at refs/notes/commits~$i" &&
+				continue
+			fi
+		fi &&
+		echo "Failed fanout=$fanout check at refs/notes/commits~$i" &&
+		git ls-tree -r --name-only refs/notes/commits~$i &&
+		return 1
+	done &&
+	all_notes_have_fanout refs/notes/commits 1
 '
 
 test_expect_success 'deleting most notes with git-notes' '
-	num_notes=250 &&
+	remove_notes=285 &&
 	i=0 &&
 	git rev-list HEAD |
-	while test $i -lt $num_notes && read sha1
+	while test $i -lt $remove_notes && read sha1
 	do
 		i=$(($i + 1)) &&
 		test_tick &&
-		git notes remove "$sha1" ||
-		exit 1
+		git notes remove "$sha1" 2>/dev/null || return 1
 	done
 '
 
 test_expect_success 'most notes deleted correctly with git-notes' '
-	git log HEAD~250 | grep "^    " > output &&
-	i=50 &&
+	git log HEAD~$remove_notes | grep "^    " > output &&
+	i=$(($num_notes - $remove_notes)) &&
 	while test $i -gt 0
 	do
 		echo "    commit #$i" &&
@@ -72,21 +111,29 @@ test_expect_success 'most notes deleted correctly with git-notes' '
 	test_cmp expect output
 '
 
-test_expect_success 'deleting most notes triggers fanout consolidation' '
-	# Expect entire notes tree to have a fanout == 0
-	git ls-tree -r --name-only refs/notes/commits |
-	while read path
+test_expect_success 'stable fanout 1 is followed by stable fanout 0' '
+	i=$remove_notes &&
+	fanout=1 &&
+	while test $i -gt 0
 	do
-		case "$path" in
-		????????????????????????????????????????)
-			: true
-			;;
-		*)
-			echo "Invalid path \"$path\"" &&
-			return 1
-			;;
-		esac
-	done
+		i=$(($i - 1)) &&
+		if touched_one_note_with_fanout refs/notes/commits~$i D $fanout
+		then
+			continue
+		elif test $fanout -eq 1
+		then
+			fanout=0 &&
+			if all_notes_have_fanout refs/notes/commits~$i $fanout
+			then
+				echo "Fanout 1 -> 0 at refs/notes/commits~$i" &&
+				continue
+			fi
+		fi &&
+		echo "Failed fanout=$fanout check at refs/notes/commits~$i" &&
+		git ls-tree -r --name-only refs/notes/commits~$i &&
+		return 1
+	done &&
+	all_notes_have_fanout refs/notes/commits 0
 '
 
 test_done