26 files changed, 1229 insertions, 31 deletions

diff --git a/t/helper/.gitignore b/t/helper/.gitignore
index 7c9d28a834..d02f9b39ac 100644
--- a/t/helper/.gitignore
+++ b/t/helper/.gitignore
@@ -3,7 +3,9 @@
 /test-config
 /test-date
 /test-delta
+/test-drop-caches
 /test-dump-cache-tree
+/test-dump-fsmonitor
 /test-dump-split-index
 /test-dump-untracked-cache
 /test-fake-ssh
diff --git a/t/helper/test-drop-caches.c b/t/helper/test-drop-caches.c
new file mode 100644
index 0000000000..bd1a857d52
--- /dev/null
+++ b/t/helper/test-drop-caches.c
@@ -0,0 +1,164 @@
+#include "git-compat-util.h"
+
+#if defined(GIT_WINDOWS_NATIVE)
+
+static int cmd_sync(void)
+{
+	char Buffer[MAX_PATH];
+	DWORD dwRet;
+	char szVolumeAccessPath[] = "\\\\.\\X:";
+	HANDLE hVolWrite;
+	int success = 0;
+
+	dwRet = GetCurrentDirectory(MAX_PATH, Buffer);
+	if ((0 == dwRet) || (dwRet > MAX_PATH))
+		return error("Error getting current directory");
+
+	if ((Buffer[0] < 'A') || (Buffer[0] > 'Z'))
+		return error("Invalid drive letter '%c'", Buffer[0]);
+
+	szVolumeAccessPath[4] = Buffer[0];
+	hVolWrite = CreateFile(szVolumeAccessPath, GENERIC_READ | GENERIC_WRITE,
+		FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
+	if (INVALID_HANDLE_VALUE == hVolWrite)
+		return error("Unable to open volume for writing, need admin access");
+
+	success = FlushFileBuffers(hVolWrite);
+	if (!success)
+		error("Unable to flush volume");
+
+	CloseHandle(hVolWrite);
+
+	return !success;
+}
+
+#define STATUS_SUCCESS			(0x00000000L)
+#define STATUS_PRIVILEGE_NOT_HELD	(0xC0000061L)
+
+typedef enum _SYSTEM_INFORMATION_CLASS {
+	SystemMemoryListInformation = 80,
+} SYSTEM_INFORMATION_CLASS;
+
+typedef enum _SYSTEM_MEMORY_LIST_COMMAND {
+	MemoryCaptureAccessedBits,
+	MemoryCaptureAndResetAccessedBits,
+	MemoryEmptyWorkingSets,
+	MemoryFlushModifiedList,
+	MemoryPurgeStandbyList,
+	MemoryPurgeLowPriorityStandbyList,
+	MemoryCommandMax
+} SYSTEM_MEMORY_LIST_COMMAND;
+
+static BOOL GetPrivilege(HANDLE TokenHandle, LPCSTR lpName, int flags)
+{
+	BOOL bResult;
+	DWORD dwBufferLength;
+	LUID luid;
+	TOKEN_PRIVILEGES tpPreviousState;
+	TOKEN_PRIVILEGES tpNewState;
+
+	dwBufferLength = 16;
+	bResult = LookupPrivilegeValueA(0, lpName, &luid);
+	if (bResult) {
+		tpNewState.PrivilegeCount = 1;
+		tpNewState.Privileges[0].Luid = luid;
+		tpNewState.Privileges[0].Attributes = 0;
+		bResult = AdjustTokenPrivileges(TokenHandle, 0, &tpNewState,
+			(DWORD)((LPBYTE)&(tpNewState.Privileges[1]) - (LPBYTE)&tpNewState),
+			&tpPreviousState, &dwBufferLength);
+		if (bResult) {
+			tpPreviousState.PrivilegeCount = 1;
+			tpPreviousState.Privileges[0].Luid = luid;
+			tpPreviousState.Privileges[0].Attributes = flags != 0 ? 2 : 0;
+			bResult = AdjustTokenPrivileges(TokenHandle, 0, &tpPreviousState,
+				dwBufferLength, 0, 0);
+		}
+	}
+	return bResult;
+}
+
+static int cmd_dropcaches(void)
+{
+	HANDLE hProcess = GetCurrentProcess();
+	HANDLE hToken;
+	HMODULE ntdll;
+	DWORD(WINAPI *NtSetSystemInformation)(INT, PVOID, ULONG);
+	SYSTEM_MEMORY_LIST_COMMAND command;
+	int status;
+
+	if (!OpenProcessToken(hProcess, TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, &hToken))
+		return error("Can't open current process token");
+
+	if (!GetPrivilege(hToken, "SeProfileSingleProcessPrivilege", 1))
+		return error("Can't get SeProfileSingleProcessPrivilege");
+
+	CloseHandle(hToken);
+
+	ntdll = LoadLibrary("ntdll.dll");
+	if (!ntdll)
+		return error("Can't load ntdll.dll, wrong Windows version?");
+
+	NtSetSystemInformation =
+		(DWORD(WINAPI *)(INT, PVOID, ULONG))GetProcAddress(ntdll, "NtSetSystemInformation");
+	if (!NtSetSystemInformation)
+		return error("Can't get function addresses, wrong Windows version?");
+
+	command = MemoryPurgeStandbyList;
+	status = NtSetSystemInformation(
+		SystemMemoryListInformation,
+		&command,
+		sizeof(SYSTEM_MEMORY_LIST_COMMAND)
+	);
+	if (status == STATUS_PRIVILEGE_NOT_HELD)
+		error("Insufficient privileges to purge the standby list, need admin access");
+	else if (status != STATUS_SUCCESS)
+		error("Unable to execute the memory list command %d", status);
+
+	FreeLibrary(ntdll);
+
+	return status;
+}
+
+#elif defined(__linux__)
+
+static int cmd_sync(void)
+{
+	return system("sync");
+}
+
+static int cmd_dropcaches(void)
+{
+	return system("echo 3 | sudo tee /proc/sys/vm/drop_caches");
+}
+
+#elif defined(__APPLE__)
+
+static int cmd_sync(void)
+{
+	return system("sync");
+}
+
+static int cmd_dropcaches(void)
+{
+	return system("sudo purge");
+}
+
+#else
+
+static int cmd_sync(void)
+{
+	return 0;
+}
+
+static int cmd_dropcaches(void)
+{
+	return error("drop caches not implemented on this platform");
+}
+
+#endif
+
+int cmd_main(int argc, const char **argv)
+{
+	cmd_sync();
+	return cmd_dropcaches();
+}
diff --git a/t/helper/test-dump-fsmonitor.c b/t/helper/test-dump-fsmonitor.c
new file mode 100644
index 0000000000..ad452707e8
--- /dev/null
+++ b/t/helper/test-dump-fsmonitor.c
@@ -0,0 +1,21 @@
+#include "cache.h"
+
+int cmd_main(int ac, const char **av)
+{
+	struct index_state *istate = &the_index;
+	int i;
+
+	setup_git_directory();
+	if (do_read_index(istate, get_index_file(), 0) < 0)
+		die("unable to read index file");
+	if (!istate->fsmonitor_last_update) {
+		printf("no fsmonitor\n");
+		return 0;
+	}
+	printf("fsmonitor last update %"PRIuMAX"\n", (uintmax_t)istate->fsmonitor_last_update);
+
+	for (i = 0; i < istate->cache_nr; i++)
+		printf((istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) ? "+" : "-");
+
+	return 0;
+}
diff --git a/t/lib-gpg.sh b/t/lib-gpg.sh
index 43679a4c64..a5d3b2cbaa 100755
--- a/t/lib-gpg.sh
+++ b/t/lib-gpg.sh
@@ -31,7 +31,7 @@ then
 		chmod 0700 ./gpghome &&
 		GNUPGHOME="$(pwd)/gpghome" &&
 		export GNUPGHOME &&
-		(gpgconf --kill gpg-agent 2>&1 >/dev/null || : ) &&
+		(gpgconf --kill gpg-agent >/dev/null 2>&1 || : ) &&
 		gpg --homedir "${GNUPGHOME}" 2>/dev/null --import \
 			"$TEST_DIRECTORY"/lib-gpg/keyring.gpg &&
 		gpg --homedir "${GNUPGHOME}" 2>/dev/null --import-ownertrust \
diff --git a/t/lib-submodule-update.sh b/t/lib-submodule-update.sh
index bb94c23209..9058bf978a 100755
--- a/t/lib-submodule-update.sh
+++ b/t/lib-submodule-update.sh
@@ -689,6 +689,23 @@ test_submodule_switch_recursing_with_args () {
 			test_submodule_content sub1 origin/add_sub1
 		)
 	'
+	test_expect_success "$command: submodule branch is not changed, detach HEAD instead" '
+		prolog &&
+		reset_work_tree_to_interested add_sub1 &&
+		(
+			cd submodule_update &&
+			git -C sub1 checkout -b keep_branch &&
+			git -C sub1 rev-parse HEAD >expect &&
+			git branch -t check-keep origin/modify_sub1 &&
+			$command check-keep &&
+			test_superproject_content origin/modify_sub1 &&
+			test_submodule_content sub1 origin/modify_sub1 &&
+			git -C sub1 rev-parse keep_branch >actual &&
+			test_cmp expect actual &&
+			test_must_fail git -C sub1 symbolic-ref HEAD
+		)
+	'
+
 	# Replacing a tracked file with a submodule produces a checked out submodule
 	test_expect_success "$command: replace tracked file with submodule checks out submodule" '
 		prolog &&
diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 1dbc85b214..e401208488 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -69,12 +69,17 @@ if (not @tests) {
 	@tests = glob "p????-*.sh";
 }
 
+my $resultsdir = "test-results";
+if ($ENV{GIT_PERF_SUBSECTION} ne "") {
+	$resultsdir .= "/" . $ENV{GIT_PERF_SUBSECTION};
+}
+
 my @subtests;
 my %shorttests;
 for my $t (@tests) {
 	$t =~ s{(?:.*/)?(p(\d+)-[^/]+)\.sh$}{$1} or die "bad test name: $t";
 	my $n = $2;
-	my $fname = "test-results/$t.subtests";
+	my $fname = "$resultsdir/$t.subtests";
 	open my $fp, "<", $fname or die "cannot open $fname: $!";
 	for (<$fp>) {
 		chomp;
@@ -98,7 +103,7 @@ sub read_descr {
 my %descrs;
 my $descrlen = 4; # "Test"
 for my $t (@subtests) {
-	$descrs{$t} = $shorttests{$t}.": ".read_descr("test-results/$t.descr");
+	$descrs{$t} = $shorttests{$t}.": ".read_descr("$resultsdir/$t.descr");
 	$descrlen = length $descrs{$t} if length $descrs{$t}>$descrlen;
 }
 
@@ -138,7 +143,7 @@ for my $t (@subtests) {
 	my $firstr;
 	for my $i (0..$#dirs) {
 		my $d = $dirs[$i];
-		$times{$prefixes{$d}.$t} = [get_times("test-results/$prefixes{$d}$t.times")];
+		$times{$prefixes{$d}.$t} = [get_times("$resultsdir/$prefixes{$d}$t.times")];
 		my ($r,$u,$s) = @{$times{$prefixes{$d}.$t}};
 		my $w = length format_times($r,$u,$s,$firstr);
 		$colwidth[$i] = $w if $w > $colwidth[$i];
diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh
new file mode 100755
index 0000000000..16d1bf72e5
--- /dev/null
+++ b/t/perf/p7519-fsmonitor.sh
@@ -0,0 +1,184 @@
+#!/bin/sh
+
+test_description="Test core.fsmonitor"
+
+. ./perf-lib.sh
+
+#
+# Performance test for the fsmonitor feature which enables git to talk to a
+# file system change monitor and avoid having to scan the working directory
+# for new or modified files.
+#
+# By default, the performance test will utilize the Watchman file system
+# monitor if it is installed.  If Watchman is not installed, it will use a
+# dummy integration script that does not report any new or modified files.
+# The dummy script has very little overhead which provides optimistic results.
+#
+# The performance test will also use the untracked cache feature if it is
+# available as fsmonitor uses it to speed up scanning for untracked files.
+#
+# There are 3 environment variables that can be used to alter the default
+# behavior of the performance test:
+#
+# GIT_PERF_7519_UNTRACKED_CACHE: used to configure core.untrackedCache
+# GIT_PERF_7519_SPLIT_INDEX: used to configure core.splitIndex
+# GIT_PERF_7519_FSMONITOR: used to configure core.fsMonitor
+#
+# The big win for using fsmonitor is the elimination of the need to scan the
+# working directory looking for changed and untracked files. If the file
+# information is all cached in RAM, the benefits are reduced.
+#
+# GIT_PERF_7519_DROP_CACHE: if set, the OS caches are dropped between tests
+#
+
+test_perf_large_repo
+test_checkout_worktree
+
+test_lazy_prereq UNTRACKED_CACHE '
+	{ git update-index --test-untracked-cache; ret=$?; } &&
+	test $ret -ne 1
+'
+
+test_lazy_prereq WATCHMAN '
+	{ command -v watchman >/dev/null 2>&1; ret=$?; } &&
+	test $ret -ne 1
+'
+
+if test_have_prereq WATCHMAN
+then
+	# Convert unix style paths to escaped Windows style paths for Watchman
+	case "$(uname -s)" in
+	MSYS_NT*)
+	  GIT_WORK_TREE="$(cygpath -aw "$PWD" | sed 's,\\,/,g')"
+	  ;;
+	*)
+	  GIT_WORK_TREE="$PWD"
+	  ;;
+	esac
+fi
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"
+then
+	# When using GIT_PERF_7519_DROP_CACHE, GIT_PERF_REPEAT_COUNT must be 1 to
+	# generate valid results. Otherwise the caching that happens for the nth
+	# run will negate the validity of the comparisons.
+	if test "$GIT_PERF_REPEAT_COUNT" -ne 1
+	then
+		echo "warning: Setting GIT_PERF_REPEAT_COUNT=1" >&2
+		GIT_PERF_REPEAT_COUNT=1
+	fi
+fi
+
+test_expect_success "setup for fsmonitor" '
+	# set untrackedCache depending on the environment
+	if test -n "$GIT_PERF_7519_UNTRACKED_CACHE"
+	then
+		git config core.untrackedCache "$GIT_PERF_7519_UNTRACKED_CACHE"
+	else
+		if test_have_prereq UNTRACKED_CACHE
+		then
+			git config core.untrackedCache true
+		else
+			git config core.untrackedCache false
+		fi
+	fi &&
+
+	# set core.splitindex depending on the environment
+	if test -n "$GIT_PERF_7519_SPLIT_INDEX"
+	then
+		git config core.splitIndex "$GIT_PERF_7519_SPLIT_INDEX"
+	fi &&
+
+	# set INTEGRATION_SCRIPT depending on the environment
+	if test -n "$GIT_PERF_7519_FSMONITOR"
+	then
+		INTEGRATION_SCRIPT="$GIT_PERF_7519_FSMONITOR"
+	else
+		#
+		# Choose integration script based on existence of Watchman.
+		# If Watchman exists, watch the work tree and attempt a query.
+		# If everything succeeds, use Watchman integration script,
+		# else fall back to an empty integration script.
+		#
+		mkdir .git/hooks &&
+		if test_have_prereq WATCHMAN
+		then
+			INTEGRATION_SCRIPT=".git/hooks/fsmonitor-watchman" &&
+			cp "$TEST_DIRECTORY/../templates/hooks--fsmonitor-watchman.sample" "$INTEGRATION_SCRIPT" &&
+			watchman watch "$GIT_WORK_TREE" &&
+			watchman watch-list | grep -q -F "$GIT_WORK_TREE"
+		else
+			INTEGRATION_SCRIPT=".git/hooks/fsmonitor-empty" &&
+			write_script "$INTEGRATION_SCRIPT"<<-\EOF
+			EOF
+		fi
+	fi &&
+
+	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
+	git update-index --fsmonitor
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uno
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uall
+'
+
+test_expect_success "setup without fsmonitor" '
+	unset INTEGRATION_SCRIPT &&
+	git config --unset core.fsmonitor &&
+	git update-index --no-fsmonitor
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uno
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uall
+'
+
+if test_have_prereq WATCHMAN
+then
+	watchman watch-del "$GIT_WORK_TREE" >/dev/null 2>&1 &&
+
+	# Work around Watchman bug on Windows where it holds on to handles
+	# preventing the removal of the trash directory
+	watchman shutdown-server >/dev/null 2>&1
+fi
+
+test_done
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index b50211b259..e4c343a6b7 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -56,12 +56,10 @@ MODERN_GIT=$GIT_BUILD_DIR/bin-wrappers/git
 export MODERN_GIT
 
 perf_results_dir=$TEST_OUTPUT_DIRECTORY/test-results
+test -n "$GIT_PERF_SUBSECTION" && perf_results_dir="$perf_results_dir/$GIT_PERF_SUBSECTION"
 mkdir -p "$perf_results_dir"
 rm -f "$perf_results_dir"/$(basename "$0" .sh).subtests
 
-if test -z "$GIT_PERF_REPEAT_COUNT"; then
-	GIT_PERF_REPEAT_COUNT=3
-fi
 die_if_build_dir_not_repo () {
 	if ! ( cd "$TEST_DIRECTORY/.." &&
 		    git rev-parse --build-dir >/dev/null 2>&1 ); then
diff --git a/t/perf/run b/t/perf/run
index beb4acc0e4..43e4de49ef 100755
--- a/t/perf/run
+++ b/t/perf/run
@@ -2,9 +2,14 @@
 
 case "$1" in
 	--help)
-		echo "usage: $0 [other_git_tree...] [--] [test_scripts]"
+		echo "usage: $0 [--config file] [other_git_tree...] [--] [test_scripts]"
 		exit 0
 		;;
+	--config)
+		shift
+		GIT_PERF_CONFIG_FILE=$(cd "$(dirname "$1")"; pwd)/$(basename "$1")
+		export GIT_PERF_CONFIG_FILE
+		shift ;;
 esac
 
 die () {
@@ -29,8 +34,10 @@ unpack_git_rev () {
 	(cd "$(git rev-parse --show-cdup)" && git archive --format=tar $rev) |
 	(cd build/$rev && tar x)
 }
+
 build_git_rev () {
 	rev=$1
+	name="$2"
 	for config in config.mak config.mak.autogen config.status
 	do
 		if test -e "../../$config"
@@ -38,7 +45,7 @@ build_git_rev () {
 			cp "../../$config" "build/$rev/"
 		fi
 	done
-	echo "=== Building $rev ==="
+	echo "=== Building $rev ($name) ==="
 	(
 		cd build/$rev &&
 		if test -n "$GIT_PERF_MAKE_COMMAND"
@@ -65,7 +72,7 @@ run_dirs_helper () {
 		if [ ! -d build/$rev ]; then
 			unpack_git_rev $rev
 		fi
-		build_git_rev $rev
+		build_git_rev $rev "$mydir"
 		mydir=build/$rev
 	fi
 	if test "$mydir" = .; then
@@ -87,14 +94,78 @@ run_dirs () {
 	done
 }
 
-GIT_PERF_AGGREGATING_LATER=t
-export GIT_PERF_AGGREGATING_LATER
+get_subsections () {
+	section="$1"
+	test -z "$GIT_PERF_CONFIG_FILE" && return
+	git config -f "$GIT_PERF_CONFIG_FILE" --name-only --get-regex "$section\..*\.[^.]+" |
+	sed -e "s/$section\.\(.*\)\..*/\1/" | sort | uniq
+}
+
+get_var_from_env_or_config () {
+	env_var="$1"
+	conf_sec="$2"
+	conf_var="$3"
+	# $4 can be set to a default value
+
+	# Do nothing if the env variable is already set
+	eval "test -z \"\${$env_var+x}\"" || return
+
+	test -z "$GIT_PERF_CONFIG_FILE" && return
+
+	# Check if the variable is in the config file
+	if test -n "$GIT_PERF_SUBSECTION"
+	then
+		var="$conf_sec.$GIT_PERF_SUBSECTION.$conf_var"
+		conf_value=$(git config -f "$GIT_PERF_CONFIG_FILE" "$var") &&
+		eval "$env_var=\"$conf_value\"" && return
+	fi
+	var="$conf_sec.$conf_var"
+	conf_value=$(git config -f "$GIT_PERF_CONFIG_FILE" "$var") &&
+	eval "$env_var=\"$conf_value\"" && return
+
+	test -n "${4+x}" && eval "$env_var=\"$4\""
+}
+
+run_subsection () {
+	get_var_from_env_or_config "GIT_PERF_REPEAT_COUNT" "perf" "repeatCount" 3
+	export GIT_PERF_REPEAT_COUNT
+
+	get_var_from_env_or_config "GIT_PERF_DIRS_OR_REVS" "perf" "dirsOrRevs"
+	set -- $GIT_PERF_DIRS_OR_REVS "$@"
+
+	get_var_from_env_or_config "GIT_PERF_MAKE_COMMAND" "perf" "makeCommand"
+	get_var_from_env_or_config "GIT_PERF_MAKE_OPTS" "perf" "makeOpts"
+
+	GIT_PERF_AGGREGATING_LATER=t
+	export GIT_PERF_AGGREGATING_LATER
+
+	if test $# = 0 -o "$1" = -- -o -f "$1"; then
+		set -- . "$@"
+	fi
+
+	run_dirs "$@"
+	./aggregate.perl "$@"
+}
 
 cd "$(dirname $0)"
 . ../../GIT-BUILD-OPTIONS
 
-if test $# = 0 -o "$1" = -- -o -f "$1"; then
-	set -- . "$@"
+mkdir -p test-results
+get_subsections "perf" >test-results/run_subsections.names
+
+if test $(wc -l <test-results/run_subsections.names) -eq 0
+then
+	(
+		run_subsection "$@"
+	)
+else
+	while read -r subsec
+	do
+		(
+			GIT_PERF_SUBSECTION="$subsec"
+			export GIT_PERF_SUBSECTION
+			echo "======== Run for subsection '$GIT_PERF_SUBSECTION' ========"
+			run_subsection "$@"
+		)
+	done <test-results/run_subsections.names
 fi
-run_dirs "$@"
-./aggregate.perl "$@"
diff --git a/t/t0025-crlf-renormalize.sh b/t/t0025-crlf-renormalize.sh
new file mode 100755
index 0000000000..9d9e02a211
--- /dev/null
+++ b/t/t0025-crlf-renormalize.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+test_description='CRLF renormalization'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	git config core.autocrlf false &&
+	printf "LINEONE\nLINETWO\nLINETHREE\n" >LF.txt &&
+	printf "LINEONE\r\nLINETWO\r\nLINETHREE\r\n" >CRLF.txt &&
+	printf "LINEONE\r\nLINETWO\nLINETHREE\n" >CRLF_mix_LF.txt &&
+	git add . &&
+	git commit -m initial
+'
+
+test_expect_success 'renormalize CRLF in repo' '
+	echo "*.txt text=auto" >.gitattributes &&
+	git add --renormalize "*.txt" &&
+	cat >expect <<-\EOF &&
+	i/lf w/crlf attr/text=auto CRLF.txt
+	i/lf w/lf attr/text=auto LF.txt
+	i/lf w/mixed attr/text=auto CRLF_mix_LF.txt
+	EOF
+	git ls-files --eol |
+	sed -e "s/	/ /g" -e "s/  */ /g" |
+	sort >actual &&
+	test_cmp expect actual
+'
+
+test_done
diff --git a/t/t1430-bad-ref-name.sh b/t/t1430-bad-ref-name.sh
index e88349c8a0..c7878a60ed 100755
--- a/t/t1430-bad-ref-name.sh
+++ b/t/t1430-bad-ref-name.sh
@@ -331,4 +331,47 @@ test_expect_success 'update-ref --stdin -z fails delete with bad ref name' '
 	grep "fatal: invalid ref format: ~a" err
 '
 
+test_expect_success 'branch rejects HEAD as a branch name' '
+	test_must_fail git branch HEAD HEAD^ &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'checkout -b rejects HEAD as a branch name' '
+	test_must_fail git checkout -B HEAD HEAD^ &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'update-ref can operate on refs/heads/HEAD' '
+	git update-ref refs/heads/HEAD HEAD^ &&
+	git show-ref refs/heads/HEAD &&
+	git update-ref -d refs/heads/HEAD &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'branch -d can remove refs/heads/HEAD' '
+	git update-ref refs/heads/HEAD HEAD^ &&
+	git branch -d HEAD &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'branch -m can rename refs/heads/HEAD' '
+	git update-ref refs/heads/HEAD HEAD^ &&
+	git branch -m HEAD tail &&
+	test_must_fail git show-ref refs/heads/HEAD &&
+	git show-ref refs/heads/tail
+'
+
+test_expect_success 'branch -d can remove refs/heads/-dash' '
+	git update-ref refs/heads/-dash HEAD^ &&
+	git branch -d -- -dash &&
+	test_must_fail git show-ref refs/heads/-dash
+'
+
+test_expect_success 'branch -m can rename refs/heads/-dash' '
+	git update-ref refs/heads/-dash HEAD^ &&
+	git branch -m -- -dash dash &&
+	test_must_fail git show-ref refs/heads/-dash &&
+	git show-ref refs/heads/dash
+'
+
 test_done
diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index 22f69a410b..af9b847761 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -6,6 +6,7 @@ test_description='split index mode tests'
 
 # We need total control of index splitting here
 sane_unset GIT_TEST_SPLIT_INDEX
+sane_unset GIT_FSMONITOR_TEST
 
 test_expect_success 'enable split index' '
 	git config splitIndex.maxPercentChange 100 &&
diff --git a/t/t3310-notes-merge-manual-resolve.sh b/t/t3310-notes-merge-manual-resolve.sh
index baef2d6924..9c1bf6eb3d 100755
--- a/t/t3310-notes-merge-manual-resolve.sh
+++ b/t/t3310-notes-merge-manual-resolve.sh
@@ -176,7 +176,7 @@ git rev-parse refs/notes/z > pre_merge_z
 test_expect_success 'merge z into m (== y) with default ("manual") resolver => Conflicting 3-way merge' '
 	git update-ref refs/notes/m refs/notes/y &&
 	git config core.notesRef refs/notes/m &&
-	test_must_fail git notes merge z >output &&
+	test_must_fail git notes merge z >output 2>&1 &&
 	# Output should point to where to resolve conflicts
 	test_i18ngrep "\\.git/NOTES_MERGE_WORKTREE" output &&
 	# Inspect merge conflicts
@@ -379,7 +379,7 @@ git rev-parse refs/notes/z > pre_merge_z
 test_expect_success 'redo merge of z into m (== y) with default ("manual") resolver => Conflicting 3-way merge' '
 	git update-ref refs/notes/m refs/notes/y &&
 	git config core.notesRef refs/notes/m &&
-	test_must_fail git notes merge z >output &&
+	test_must_fail git notes merge z >output 2>&1 &&
 	# Output should point to where to resolve conflicts
 	test_i18ngrep "\\.git/NOTES_MERGE_WORKTREE" output &&
 	# Inspect merge conflicts
@@ -413,7 +413,7 @@ git rev-parse refs/notes/y > pre_merge_y
 git rev-parse refs/notes/z > pre_merge_z
 
 test_expect_success 'redo merge of z into m (== y) with default ("manual") resolver => Conflicting 3-way merge' '
-	test_must_fail git notes merge z >output &&
+	test_must_fail git notes merge z >output 2>&1 &&
 	# Output should point to where to resolve conflicts
 	test_i18ngrep "\\.git/NOTES_MERGE_WORKTREE" output &&
 	# Inspect merge conflicts
@@ -494,7 +494,7 @@ cp expect_log_y expect_log_m
 
 test_expect_success 'redo merge of z into m (== y) with default ("manual") resolver => Conflicting 3-way merge' '
 	git update-ref refs/notes/m refs/notes/y &&
-	test_must_fail git notes merge z >output &&
+	test_must_fail git notes merge z >output 2>&1 &&
 	# Output should point to where to resolve conflicts
 	test_i18ngrep "\\.git/NOTES_MERGE_WORKTREE" output &&
 	# Inspect merge conflicts
diff --git a/t/t3320-notes-merge-worktrees.sh b/t/t3320-notes-merge-worktrees.sh
index b9c3bc2487..10bfc8b947 100755
--- a/t/t3320-notes-merge-worktrees.sh
+++ b/t/t3320-notes-merge-worktrees.sh
@@ -61,7 +61,7 @@ test_expect_success 'merge z into x while mid-merge on y succeeds' '
 	(
 		cd worktree2 &&
 		git config core.notesRef refs/notes/x &&
-		test_must_fail git notes merge z 2>&1 >out &&
+		test_must_fail git notes merge z >out 2>&1 &&
 		test_i18ngrep "Automatic notes merge failed" out &&
 		grep -v "A notes merge into refs/notes/x is already in-progress in" out
 	) &&
diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh
index f5fd15e559..8ac58d5ea5 100755
--- a/t/t3400-rebase.sh
+++ b/t/t3400-rebase.sh
@@ -255,4 +255,26 @@ test_expect_success 'rebase commit with an ancient timestamp' '
 	grep "author .* 34567 +0600$" actual
 '
 
+test_expect_success 'rebase with "From " line in commit message' '
+	git checkout -b preserve-from master~1 &&
+	cat >From_.msg <<EOF &&
+Somebody embedded an mbox in a commit message
+
+This is from so-and-so:
+
+From a@b Mon Sep 17 00:00:00 2001
+From: John Doe <nobody@example.com>
+Date: Sat, 11 Nov 2017 00:00:00 +0000
+Subject: not this message
+
+something
+EOF
+	>From_ &&
+	git add From_ &&
+	git commit -F From_.msg &&
+	git rebase master &&
+	git log -1 --pretty=format:%B >out &&
+	test_cmp From_.msg out
+'
+
 test_done
diff --git a/t/t3512-cherry-pick-submodule.sh b/t/t3512-cherry-pick-submodule.sh
index 6863b7bb6f..ce48c4fcca 100755
--- a/t/t3512-cherry-pick-submodule.sh
+++ b/t/t3512-cherry-pick-submodule.sh
@@ -10,4 +10,40 @@ KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES=1
 test_submodule_switch "git cherry-pick"
 
+test_expect_success 'unrelated submodule/file conflict is ignored' '
+	test_create_repo sub &&
+
+	touch sub/file &&
+	git -C sub add file &&
+	git -C sub commit -m "add a file in a submodule" &&
+
+	test_create_repo a_repo &&
+	(
+		cd a_repo &&
+		>a_file &&
+		git add a_file &&
+		git commit -m "add a file" &&
+
+		git branch test &&
+		git checkout test &&
+
+		mkdir sub &&
+		>sub/content &&
+		git add sub/content &&
+		git commit -m "add a regular folder with name sub" &&
+
+		echo "123" >a_file &&
+		git add a_file &&
+		git commit -m "modify a file" &&
+
+		git checkout master &&
+
+		git submodule add ../sub sub &&
+		git submodule update sub &&
+		git commit -m "add a submodule info folder with name sub" &&
+
+		git cherry-pick test
+	)
+'
+
 test_done
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 6c9a93b734..559a7541a8 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -106,6 +106,8 @@ test_expect_success 'another test, without options' '
 	git diff -w -b --ignore-space-at-eol >out &&
 	test_cmp expect out &&
 
+	git diff -w --ignore-cr-at-eol >out &&
+	test_cmp expect out &&
 
 	tr "Q_" "\015 " <<-\EOF >expect &&
 	diff --git a/x b/x
@@ -128,6 +130,9 @@ test_expect_success 'another test, without options' '
 	git diff -b --ignore-space-at-eol >out &&
 	test_cmp expect out &&
 
+	git diff -b --ignore-cr-at-eol >out &&
+	test_cmp expect out &&
+
 	tr "Q_" "\015 " <<-\EOF >expect &&
 	diff --git a/x b/x
 	index d99af23..22d9f73 100644
@@ -145,6 +150,29 @@ test_expect_success 'another test, without options' '
 	 CR at end
 	EOF
 	git diff --ignore-space-at-eol >out &&
+	test_cmp expect out &&
+
+	git diff --ignore-space-at-eol --ignore-cr-at-eol >out &&
+	test_cmp expect out &&
+
+	tr "Q_" "\015 " <<-\EOF >expect &&
+	diff --git a/x b/x
+	index_d99af23..22d9f73 100644
+	--- a/x
+	+++ b/x
+	@@ -1,6 +1,6 @@
+	-whitespace at beginning
+	-whitespace change
+	-whitespace in the middle
+	-whitespace at end
+	+_	whitespace at beginning
+	+whitespace_	_change
+	+white space in the middle
+	+whitespace at end__
+	 unchanged line
+	 CR at end
+	EOF
+	git diff --ignore-cr-at-eol >out &&
 	test_cmp expect out
 '
 
diff --git a/t/t4051-diff-function-context.sh b/t/t4051-diff-function-context.sh
index 3e6b485ecb..2d76a971c4 100755
--- a/t/t4051-diff-function-context.sh
+++ b/t/t4051-diff-function-context.sh
@@ -85,6 +85,10 @@ test_expect_success 'setup' '
 
 check_diff changed_hello 'changed function'
 
+test_expect_success ' context includes comment' '
+	grep "^ .*Hello comment" changed_hello.diff
+'
+
 test_expect_success ' context includes begin' '
 	grep "^ .*Begin of hello" changed_hello.diff
 '
diff --git a/t/t4051/hello.c b/t/t4051/hello.c
index 63b1a1e4ef..73e767e178 100644
--- a/t/t4051/hello.c
+++ b/t/t4051/hello.c
@@ -1,4 +1,7 @@
 
+/*
+ * Hello comment.
+ */
 static void hello(void)	// Begin of hello
 {
 	/*
diff --git a/t/t4107-apply-ignore-whitespace.sh b/t/t4107-apply-ignore-whitespace.sh
index 9e29b5262d..ac72eeaf27 100755
--- a/t/t4107-apply-ignore-whitespace.sh
+++ b/t/t4107-apply-ignore-whitespace.sh
@@ -178,4 +178,18 @@ test_expect_success 'patch5 fails (--no-ignore-whitespace)' '
 	test_must_fail git apply --no-ignore-whitespace patch5.patch
 '
 
+test_expect_success 'apply --ignore-space-change --inaccurate-eof' '
+	echo 1 >file &&
+	git apply --ignore-space-change --inaccurate-eof <<-\EOF &&
+	diff --git a/file b/file
+	--- a/file
+	+++ b/file
+	@@ -1 +1 @@
+	-1
+	+2
+	EOF
+	printf 2 >expect &&
+	test_cmp expect file
+'
+
 test_done
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 865168ec6a..f5f46a95b4 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -214,6 +214,44 @@ test_expect_success TTY 'git tag as alias respects pager.tag with -l' '
 	! test -e paginated.out
 '
 
+test_expect_success TTY 'git branch defaults to paging' '
+	rm -f paginated.out &&
+	test_terminal git branch &&
+	test -e paginated.out
+'
+
+test_expect_success TTY 'git branch respects pager.branch' '
+	rm -f paginated.out &&
+	test_terminal git -c pager.branch=false branch &&
+	! test -e paginated.out
+'
+
+test_expect_success TTY 'git branch respects --no-pager' '
+	rm -f paginated.out &&
+	test_terminal git --no-pager branch &&
+	! test -e paginated.out
+'
+
+test_expect_success TTY 'git branch --edit-description ignores pager.branch' '
+	rm -f paginated.out editor.used &&
+	write_script editor <<-\EOF &&
+		echo "New description" >"$1"
+		touch editor.used
+	EOF
+	EDITOR=./editor test_terminal git -c pager.branch branch --edit-description &&
+	! test -e paginated.out &&
+	test -e editor.used
+'
+
+test_expect_success TTY 'git branch --set-upstream-to ignores pager.branch' '
+	rm -f paginated.out &&
+	git branch other &&
+	test_when_finished "git branch -D other" &&
+	test_terminal git -c pager.branch branch --set-upstream-to=other &&
+	test_when_finished "git branch --unset-upstream" &&
+	! test -e paginated.out
+'
+
 # A colored commit log will begin with an appropriate ANSI escape
 # for the first color; the text "commit" comes later.
 colorful() {
diff --git a/t/t7519-status-fsmonitor.sh b/t/t7519-status-fsmonitor.sh
new file mode 100755
index 0000000000..eb2d13bbcf
--- /dev/null
+++ b/t/t7519-status-fsmonitor.sh
@@ -0,0 +1,317 @@
+#!/bin/sh
+
+test_description='git status with file system watcher'
+
+. ./test-lib.sh
+
+#
+# To run the entire git test suite using fsmonitor:
+#
+# copy t/t7519/fsmonitor-all to a location in your path and then set
+# GIT_FSMONITOR_TEST=fsmonitor-all and run your tests.
+#
+
+# Note, after "git reset --hard HEAD" no extensions exist other than 'TREE'
+# "git update-index --fsmonitor" can be used to get the extension written
+# before testing the results.
+
+clean_repo () {
+	git reset --hard HEAD &&
+	git clean -fd
+}
+
+dirty_repo () {
+	: >untracked &&
+	: >dir1/untracked &&
+	: >dir2/untracked &&
+	echo 1 >modified &&
+	echo 2 >dir1/modified &&
+	echo 3 >dir2/modified &&
+	echo 4 >new &&
+	echo 5 >dir1/new &&
+	echo 6 >dir2/new
+}
+
+write_integration_script () {
+	write_script .git/hooks/fsmonitor-test<<-\EOF
+	if test "$#" -ne 2
+	then
+		echo "$0: exactly 2 arguments expected"
+		exit 2
+	fi
+	if test "$1" != 1
+	then
+		echo "Unsupported core.fsmonitor hook version." >&2
+		exit 1
+	fi
+	printf "untracked\0"
+	printf "dir1/untracked\0"
+	printf "dir2/untracked\0"
+	printf "modified\0"
+	printf "dir1/modified\0"
+	printf "dir2/modified\0"
+	printf "new\0"
+	printf "dir1/new\0"
+	printf "dir2/new\0"
+	EOF
+}
+
+test_lazy_prereq UNTRACKED_CACHE '
+	{ git update-index --test-untracked-cache; ret=$?; } &&
+	test $ret -ne 1
+'
+
+test_expect_success 'setup' '
+	mkdir -p .git/hooks &&
+	: >tracked &&
+	: >modified &&
+	mkdir dir1 &&
+	: >dir1/tracked &&
+	: >dir1/modified &&
+	mkdir dir2 &&
+	: >dir2/tracked &&
+	: >dir2/modified &&
+	git -c core.fsmonitor= add . &&
+	git -c core.fsmonitor= commit -m initial &&
+	git config core.fsmonitor .git/hooks/fsmonitor-test &&
+	cat >.gitignore <<-\EOF
+	.gitignore
+	expect*
+	actual*
+	marker*
+	EOF
+'
+
+# test that the fsmonitor extension is off by default
+test_expect_success 'fsmonitor extension is off by default' '
+	test-dump-fsmonitor >actual &&
+	grep "^no fsmonitor" actual
+'
+
+# test that "update-index --fsmonitor" adds the fsmonitor extension
+test_expect_success 'update-index --fsmonitor" adds the fsmonitor extension' '
+	git update-index --fsmonitor &&
+	test-dump-fsmonitor >actual &&
+	grep "^fsmonitor last update" actual
+'
+
+# test that "update-index --no-fsmonitor" removes the fsmonitor extension
+test_expect_success 'update-index --no-fsmonitor" removes the fsmonitor extension' '
+	git update-index --no-fsmonitor &&
+	test-dump-fsmonitor >actual &&
+	grep "^no fsmonitor" actual
+'
+
+cat >expect <<EOF &&
+h dir1/modified
+H dir1/tracked
+h dir2/modified
+H dir2/tracked
+h modified
+H tracked
+EOF
+
+# test that "update-index --fsmonitor-valid" sets the fsmonitor valid bit
+test_expect_success 'update-index --fsmonitor-valid" sets the fsmonitor valid bit' '
+	git update-index --fsmonitor &&
+	git update-index --fsmonitor-valid dir1/modified &&
+	git update-index --fsmonitor-valid dir2/modified &&
+	git update-index --fsmonitor-valid modified &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<EOF &&
+H dir1/modified
+H dir1/tracked
+H dir2/modified
+H dir2/tracked
+H modified
+H tracked
+EOF
+
+# test that "update-index --no-fsmonitor-valid" clears the fsmonitor valid bit
+test_expect_success 'update-index --no-fsmonitor-valid" clears the fsmonitor valid bit' '
+	git update-index --no-fsmonitor-valid dir1/modified &&
+	git update-index --no-fsmonitor-valid dir2/modified &&
+	git update-index --no-fsmonitor-valid modified &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<EOF &&
+H dir1/modified
+H dir1/tracked
+H dir2/modified
+H dir2/tracked
+H modified
+H tracked
+EOF
+
+# test that all files returned by the script get flagged as invalid
+test_expect_success 'all files returned by integration script get flagged as invalid' '
+	write_integration_script &&
+	dirty_repo &&
+	git update-index --fsmonitor &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<EOF &&
+H dir1/modified
+h dir1/new
+H dir1/tracked
+H dir2/modified
+h dir2/new
+H dir2/tracked
+H modified
+h new
+H tracked
+EOF
+
+# test that newly added files are marked valid
+test_expect_success 'newly added files are marked valid' '
+	git add new &&
+	git add dir1/new &&
+	git add dir2/new &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<EOF &&
+H dir1/modified
+h dir1/new
+h dir1/tracked
+H dir2/modified
+h dir2/new
+h dir2/tracked
+H modified
+h new
+h tracked
+EOF
+
+# test that all unmodified files get marked valid
+test_expect_success 'all unmodified files get marked valid' '
+	# modified files result in update-index returning 1
+	test_must_fail git update-index --refresh --force-write-index &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<EOF &&
+H dir1/modified
+h dir1/tracked
+h dir2/modified
+h dir2/tracked
+h modified
+h tracked
+EOF
+
+# test that *only* files returned by the integration script get flagged as invalid
+test_expect_success '*only* files returned by the integration script get flagged as invalid' '
+	write_script .git/hooks/fsmonitor-test<<-\EOF &&
+	printf "dir1/modified\0"
+	EOF
+	clean_repo &&
+	git update-index --refresh --force-write-index &&
+	echo 1 >modified &&
+	echo 2 >dir1/modified &&
+	echo 3 >dir2/modified &&
+	test_must_fail git update-index --refresh --force-write-index &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+# Ensure commands that call refresh_index() to move the index back in time
+# properly invalidate the fsmonitor cache
+test_expect_success 'refresh_index() invalidates fsmonitor cache' '
+	write_script .git/hooks/fsmonitor-test<<-\EOF &&
+	EOF
+	clean_repo &&
+	dirty_repo &&
+	git add . &&
+	git commit -m "to reset" &&
+	git reset HEAD~1 &&
+	git status >actual &&
+	git -c core.fsmonitor= status >expect &&
+	test_i18ncmp expect actual
+'
+
+# test fsmonitor with and without preloadIndex
+preload_values="false true"
+for preload_val in $preload_values
+do
+	test_expect_success "setup preloadIndex to $preload_val" '
+		git config core.preloadIndex $preload_val &&
+		if test $preload_val = true
+		then
+			GIT_FORCE_PRELOAD_TEST=$preload_val; export GIT_FORCE_PRELOAD_TEST
+		else
+			unset GIT_FORCE_PRELOAD_TEST
+		fi
+	'
+
+	# test fsmonitor with and without the untracked cache (if available)
+	uc_values="false"
+	test_have_prereq UNTRACKED_CACHE && uc_values="false true"
+	for uc_val in $uc_values
+	do
+		test_expect_success "setup untracked cache to $uc_val" '
+			git config core.untrackedcache $uc_val
+		'
+
+		# Status is well tested elsewhere so we'll just ensure that the results are
+		# the same when using core.fsmonitor.
+		test_expect_success 'compare status with and without fsmonitor' '
+			write_integration_script &&
+			clean_repo &&
+			dirty_repo &&
+			git add new &&
+			git add dir1/new &&
+			git add dir2/new &&
+			git status >actual &&
+			git -c core.fsmonitor= status >expect &&
+			test_i18ncmp expect actual
+		'
+
+		# Make sure it's actually skipping the check for modified and untracked
+		# (if enabled) files unless it is told about them.
+		test_expect_success "status doesn't detect unreported modifications" '
+			write_script .git/hooks/fsmonitor-test<<-\EOF &&
+			:>marker
+			EOF
+			clean_repo &&
+			git status &&
+			test_path_is_file marker &&
+			dirty_repo &&
+			rm -f marker &&
+			git status >actual &&
+			test_path_is_file marker &&
+			test_i18ngrep ! "Changes not staged for commit:" actual &&
+			if test $uc_val = true
+			then
+				test_i18ngrep ! "Untracked files:" actual
+			fi &&
+			if test $uc_val = false
+			then
+				test_i18ngrep "Untracked files:" actual
+			fi &&
+			rm -f marker
+		'
+	done
+done
+
+# test that splitting the index dosn't interfere
+test_expect_success 'splitting the index results in the same state' '
+	write_integration_script &&
+	dirty_repo &&
+	git update-index --fsmonitor  &&
+	git ls-files -f >expect &&
+	test-dump-fsmonitor >&2 && echo &&
+	git update-index --fsmonitor --split-index &&
+	test-dump-fsmonitor >&2 && echo &&
+	git ls-files -f >actual &&
+	test_cmp expect actual
+'
+
+test_done
diff --git a/t/t7519/fsmonitor-all b/t/t7519/fsmonitor-all
new file mode 100755
index 0000000000..691bc94dc2
--- /dev/null
+++ b/t/t7519/fsmonitor-all
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# An test hook script to integrate with git to test fsmonitor.
+#
+# The hook is passed a version (currently 1) and a time in nanoseconds
+# formatted as a string and outputs to stdout all files that have been
+# modified since the given time. Paths must be relative to the root of
+# the working tree and separated by a single NUL.
+#
+#echo "$0 $*" >&2
+
+if test "$#" -ne 2
+then
+	echo "$0: exactly 2 arguments expected" >&2
+	exit 2
+fi
+
+if test "$1" != 1
+then
+	echo "Unsupported core.fsmonitor hook version." >&2
+	exit 1
+fi
+
+echo "/"
diff --git a/t/t7519/fsmonitor-none b/t/t7519/fsmonitor-none
new file mode 100755
index 0000000000..ed9cf5a6a9
--- /dev/null
+++ b/t/t7519/fsmonitor-none
@@ -0,0 +1,22 @@
+#!/bin/sh
+#
+# An test hook script to integrate with git to test fsmonitor.
+#
+# The hook is passed a version (currently 1) and a time in nanoseconds
+# formatted as a string and outputs to stdout all files that have been
+# modified since the given time. Paths must be relative to the root of
+# the working tree and separated by a single NUL.
+#
+#echo "$0 $*" >&2
+
+if test "$#" -ne 2
+then
+	echo "$0: exactly 2 arguments expected" >&2
+	exit 2
+fi
+
+if test "$1" != 1
+then
+	echo "Unsupported core.fsmonitor hook version." >&2
+	exit 1
+fi
diff --git a/t/t7519/fsmonitor-watchman b/t/t7519/fsmonitor-watchman
new file mode 100755
index 0000000000..5514edcf68
--- /dev/null
+++ b/t/t7519/fsmonitor-watchman
@@ -0,0 +1,133 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use IPC::Open2;
+
+# An example hook script to integrate Watchman
+# (https://facebook.github.io/watchman/) with git to speed up detecting
+# new and modified files.
+#
+# The hook is passed a version (currently 1) and a time in nanoseconds
+# formatted as a string and outputs to stdout all files that have been
+# modified since the given time. Paths must be relative to the root of
+# the working tree and separated by a single NUL.
+#
+# To enable this hook, rename this file to "query-watchman" and set
+# 'git config core.fsmonitor .git/hooks/query-watchman'
+#
+my ($version, $time) = @ARGV;
+#print STDERR "$0 $version $time\n";
+
+# Check the hook interface version
+
+if ($version == 1) {
+	# convert nanoseconds to seconds
+	$time = int $time / 1000000000;
+} else {
+	die "Unsupported query-fsmonitor hook version '$version'.\n" .
+	    "Falling back to scanning...\n";
+}
+
+my $git_work_tree;
+if ($^O =~ 'msys' || $^O =~ 'cygwin') {
+	$git_work_tree = Win32::GetCwd();
+	$git_work_tree =~ tr/\\/\//;
+} else {
+	require Cwd;
+	$git_work_tree = Cwd::cwd();
+}
+
+my $retry = 1;
+
+launch_watchman();
+
+sub launch_watchman {
+
+	my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
+	    or die "open2() failed: $!\n" .
+	    "Falling back to scanning...\n";
+
+	# In the query expression below we're asking for names of files that
+	# changed since $time but were not transient (ie created after
+	# $time but no longer exist).
+	#
+	# To accomplish this, we're using the "since" generator to use the
+	# recency index to select candidate nodes and "fields" to limit the
+	# output to file names only. Then we're using the "expression" term to
+	# further constrain the results.
+	#
+	# The category of transient files that we want to ignore will have a
+	# creation clock (cclock) newer than $time_t value and will also not
+	# currently exist.
+
+	my $query = <<"	END";
+		["query", "$git_work_tree", {
+			"since": $time,
+			"fields": ["name"],
+			"expression": ["not", ["allof", ["since", $time, "cclock"], ["not", "exists"]]]
+		}]
+	END
+	
+	open (my $fh, ">", ".git/watchman-query.json");
+	print $fh $query;
+	close $fh;
+
+	print CHLD_IN $query;
+	close CHLD_IN;
+	my $response = do {local $/; <CHLD_OUT>};
+
+	open ($fh, ">", ".git/watchman-response.json");
+	print $fh $response;
+	close $fh;
+
+	die "Watchman: command returned no output.\n" .
+	    "Falling back to scanning...\n" if $response eq "";
+	die "Watchman: command returned invalid output: $response\n" .
+	    "Falling back to scanning...\n" unless $response =~ /^\{/;
+
+	my $json_pkg;
+	eval {
+		require JSON::XS;
+		$json_pkg = "JSON::XS";
+		1;
+	} or do {
+		require JSON::PP;
+		$json_pkg = "JSON::PP";
+	};
+
+	my $o = $json_pkg->new->utf8->decode($response);
+
+	if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) {
+		print STDERR "Adding '$git_work_tree' to watchman's watch list.\n";
+		$retry--;
+		qx/watchman watch "$git_work_tree"/;
+		die "Failed to make watchman watch '$git_work_tree'.\n" .
+		    "Falling back to scanning...\n" if $? != 0;
+
+		# Watchman will always return all files on the first query so
+		# return the fast "everything is dirty" flag to git and do the
+		# Watchman query just to get it over with now so we won't pay
+		# the cost in git to look up each individual file.
+
+		open ($fh, ">", ".git/watchman-output.out");
+		print "/\0";
+		close $fh;
+
+		print "/\0";
+		eval { launch_watchman() };
+		exit 0;
+	}
+
+	die "Watchman: $o->{error}.\n" .
+	    "Falling back to scanning...\n" if $o->{error};
+
+	open ($fh, ">", ".git/watchman-output.out");
+	binmode $fh, ":utf8";
+	print $fh @{$o->{files}};
+	close $fh;
+
+	binmode STDOUT, ":utf8";
+	local $, = "\0";
+	print @{$o->{files}};
+}
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 2a6679c2f5..c02ca735b9 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -60,6 +60,18 @@ test_expect_success setup '
 		echo " line with leading space3"
 		echo "line without leading space2"
 	} >space &&
+	cat >hello.ps1 <<-\EOF &&
+	# No-op.
+	function dummy() {}
+
+	# Say hello.
+	function hello() {
+	  echo "Hello world."
+	} # hello
+
+	# Still a no-op.
+	function dummy() {}
+	EOF
 	git add . &&
 	test_tick &&
 	git commit -m initial
@@ -766,18 +778,27 @@ test_expect_success 'grep -W shows no trailing empty lines' '
 	test_cmp expected actual
 '
 
-cat >expected <<EOF
-hello.c=	printf("Hello world.\n");
-hello.c:	return 0;
-hello.c-	/* char ?? */
-EOF
-
 test_expect_success 'grep -W with userdiff' '
 	test_when_finished "rm -f .gitattributes" &&
-	git config diff.custom.xfuncname "(printf.*|})$" &&
-	echo "hello.c diff=custom" >.gitattributes &&
-	git grep -W return >actual &&
-	test_cmp expected actual
+	git config diff.custom.xfuncname "^function .*$" &&
+	echo "hello.ps1 diff=custom" >.gitattributes &&
+	git grep -W echo >function-context-userdiff-actual
+'
+
+test_expect_success ' includes preceding comment' '
+	grep "# Say hello" function-context-userdiff-actual
+'
+
+test_expect_success ' includes function line' '
+	grep "=function hello" function-context-userdiff-actual
+'
+
+test_expect_success ' includes matching line' '
+	grep ":  echo" function-context-userdiff-actual
+'
+
+test_expect_success ' includes last line of the function' '
+	grep "} # hello" function-context-userdiff-actual
 '
 
 for threads in $(test_seq 0 10)