Merge branch 'ab/perf-installed-fix'

Performance test framework has been broken and measured the version
of Git that happens to be on $PATH, not the specified one to
measure, for a while, which has been corrected.

* ab/perf-installed-fix:
  perf-lib.sh: forbid the use of GIT_TEST_INSTALLED
  perf tests: add "bindir" prefix to git tree test results
  perf-lib.sh: remove GIT_TEST_INSTALLED from perf-lib.sh
  perf-lib.sh: make "./run <revisions>" use the correct gits
  perf aggregate: remove GIT_TEST_INSTALLED from --codespeed
  perf README: correct docs for 3c8f12c96c regression
diff --git a/t/perf/README b/t/perf/README
index be12090..c7b70e2 100644
--- a/t/perf/README
+++ b/t/perf/README
@@ -45,7 +45,7 @@
 
     $ ./p0001-rev-list.sh
     [...]
-    $ GIT_BUILD_DIR=/path/to/other/git ./p0001-rev-list.sh
+    $ ./run /path/to/other/git -- ./p0001-rev-list.sh
     [...]
     $ ./aggregate.perl . /path/to/other/git ./p0001-rev-list.sh
 
diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 76dd48f..66554d2 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -5,6 +5,7 @@
 use warnings;
 use Getopt::Long;
 use Git;
+use Cwd qw(realpath);
 
 sub get_times {
 	my $name = shift;
@@ -98,18 +99,21 @@
 while (scalar @ARGV) {
 	my $arg = $ARGV[0];
 	my $dir;
+	my $prefix = '';
 	last if -f $arg or $arg eq "--";
 	if (! -d $arg) {
 		my $rev = Git::command_oneline(qw(rev-parse --verify), $arg);
 		$dir = "build/".$rev;
+	} elsif ($arg eq '.') {
+		$dir = '.';
 	} else {
-		$arg =~ s{/*$}{};
-		$dir = $arg;
-		$dirabbrevs{$dir} = $dir;
+		$dir = realpath($arg);
+		$dirnames{$dir} = $dir;
+		$prefix .= 'bindir';
 	}
 	push @dirs, $dir;
-	$dirnames{$dir} = $arg;
-	my $prefix = $dir;
+	$dirnames{$dir} ||= $arg;
+	$prefix .= $dir;
 	$prefix =~ tr/^a-zA-Z0-9/_/c;
 	$prefixes{$dir} = $prefix . '.';
 	shift @ARGV;
@@ -311,9 +315,6 @@
 		$environment = $reponame;
 	} elsif (exists $ENV{GIT_PERF_REPO_NAME} and $ENV{GIT_PERF_REPO_NAME} ne "") {
 		$environment = $ENV{GIT_PERF_REPO_NAME};
-	} elsif (exists $ENV{GIT_TEST_INSTALLED} and $ENV{GIT_TEST_INSTALLED} ne "") {
-		$environment = $ENV{GIT_TEST_INSTALLED};
-		$environment =~ s|/bin-wrappers$||;
 	} else {
 		$environment = `uname -r`;
 		chomp $environment;
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index 169f92e..b58a43e 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -21,19 +21,21 @@
 # because it will change our working directory.
 TEST_DIRECTORY=$(pwd)/..
 TEST_OUTPUT_DIRECTORY=$(pwd)
-ABSOLUTE_GIT_TEST_INSTALLED=$(
-	test -n "$GIT_TEST_INSTALLED" && cd "$GIT_TEST_INSTALLED" && pwd)
 
 TEST_NO_CREATE_REPO=t
 TEST_NO_MALLOC_CHECK=t
 
 . ../test-lib.sh
 
-if test -z "$GIT_TEST_INSTALLED"; then
-	perf_results_prefix=
-else
-	perf_results_prefix=$(printf "%s" "${GIT_TEST_INSTALLED%/bin-wrappers}" | tr -c "[a-zA-Z0-9]" "[_*]")"."
-	GIT_TEST_INSTALLED=$ABSOLUTE_GIT_TEST_INSTALLED
+if test -n "$GIT_TEST_INSTALLED" -a -z "$PERF_SET_GIT_TEST_INSTALLED"
+then
+	error "Do not use GIT_TEST_INSTALLED with the perf tests.
+
+Instead use:
+
+    ./run <path-to-git> -- <tests>
+
+See t/perf/README for details."
 fi
 
 # Variables from test-lib that are normally internal to the tests; we
@@ -179,7 +181,7 @@
 		base=$(basename "$0" .sh)
 		echo "$test_count" >>"$perf_results_dir"/$base.subtests
 		echo "$1" >"$perf_results_dir"/$base.$test_count.descr
-		base="$perf_results_dir"/"$perf_results_prefix$(basename "$0" .sh)"."$test_count"
+		base="$perf_results_dir"/"$PERF_RESULTS_PREFIX$(basename "$0" .sh)"."$test_count"
 		"$test_wrapper_func_" "$@"
 	fi
 
diff --git a/t/perf/run b/t/perf/run
index 9aaa733..c7b8610 100755
--- a/t/perf/run
+++ b/t/perf/run
@@ -70,6 +70,24 @@
 	) || die "failed to build revision '$mydir'"
 }
 
+set_git_test_installed () {
+	mydir=$1
+
+	mydir_abs=$(cd $mydir && pwd)
+	mydir_abs_wrappers="$mydir_abs_wrappers/bin-wrappers"
+	if test -d "$mydir_abs_wrappers"
+	then
+		GIT_TEST_INSTALLED=$mydir_abs_wrappers
+	else
+		# Older versions of git lacked bin-wrappers;
+		# fallback to the files in the root.
+		GIT_TEST_INSTALLED=$mydir_abs
+	fi
+	export GIT_TEST_INSTALLED
+	PERF_SET_GIT_TEST_INSTALLED=true
+	export PERF_SET_GIT_TEST_INSTALLED
+}
+
 run_dirs_helper () {
 	mydir=${1%/}
 	shift
@@ -79,7 +97,16 @@
 	if test $# -gt 0 -a "$1" = --; then
 		shift
 	fi
-	if [ ! -d "$mydir" ]; then
+
+	PERF_RESULTS_PREFIX=
+	if test "$mydir" = "."
+	then
+		unset GIT_TEST_INSTALLED
+	elif test -d "$mydir"
+	then
+		PERF_RESULTS_PREFIX=bindir$(cd $mydir && printf "%s" "$(pwd)" | tr -c "[a-zA-Z0-9]" "_").
+		set_git_test_installed "$mydir"
+	else
 		rev=$(git rev-parse --verify "$mydir" 2>/dev/null) ||
 		die "'$mydir' is neither a directory nor a valid revision"
 		if [ ! -d build/$rev ]; then
@@ -87,16 +114,12 @@
 		fi
 		build_git_rev $rev "$mydir"
 		mydir=build/$rev
+
+		PERF_RESULTS_PREFIX=build_$rev.
+		set_git_test_installed "$mydir"
 	fi
-	if test "$mydir" = .; then
-		unset GIT_TEST_INSTALLED
-	else
-		GIT_TEST_INSTALLED="$mydir/bin-wrappers"
-		# Older versions of git lacked bin-wrappers; fallback to the
-		# files in the root.
-		test -d "$GIT_TEST_INSTALLED" || GIT_TEST_INSTALLED=$mydir
-		export GIT_TEST_INSTALLED
-	fi
+	export PERF_RESULTS_PREFIX
+
 	run_one_dir "$@"
 }