[PATCH v2 1/2] perf-lib.sh: make "./run <revisions>" use the correct gits

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: May 6, 2019, 23:23 UTC
Message-ID: <20190506232309.28538-2-avarab@gmail.com>
In-Reply-To: <20190506202451.GA19850@sigill.intra.peff.net>

Fix a really bad regression in 0baf78e7bc ("perf-lib.sh: rely on test-lib.sh for --tee handling", 2019-03-15). Since that change all runs of different <revisions> of git have used the git found in the user's $PATH, e.g. /usr/bin/git instead of the <revision> we just built and wanted to performance test.

The problem starts with GIT_TEST_INSTALLED not working like our non-perf tests with the "run" script. I.e. you can't run performance tests against a given installed git. Instead we expect to use it ourselves to point GIT_TEST_INSTALLED to the <revision> we just built.

However, we had been relying on '$(cd "$GIT_TEST_INSTALLED" && pwd)' to resolve that relative $GIT_TEST_INSTALLED to an absolute path *before* test-lib.sh was loaded, in cases where it was e.g. "build/<rev>/bin-wrappers" and we wanted "<abs_path>build/...".

This change post-dates another proposed solution by a few days[1], I didn't notice that version when I initially wrote this. I'm doing the most minimal thing to solve the regression here, a follow-up change will move this result prefix selection logic entirely into the "run" script.

This makes e.g. these cases all work:

    ./run . $PWD/../../ origin/master origin/next HEAD -- <tests>

As well as just a plain one-off:

    ./run <tests>

And, since we're passing down the new GIT_PERF_DIR_MYDIR_REL we make sure the bug relating to aggregate.perl not finding our files as described in 0baf78e7bc doesn't happen again.

What *doesn't* work is setting GIT_TEST_INSTALLED to a relative path, this will subtly fail in test-lib.sh. This has always been the case even before 0baf78e7bc, and as documented in t/README the GIT_TEST_INSTALLED variable should be set to an absolute path (needs to be set "to the bindir", which is always absolute). Perhaps that should be dealt with in the future, but I'm leaving that alone for now.

1. https://public-inbox.org/git/20190502222409.GA15631@sigill.intra.peff.net/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 t/perf/perf-lib.sh | 4 ++++
 t/perf/run         | 8 ++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index 169f92eae3..b15ee1d262 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -32,6 +32,10 @@ TEST_NO_MALLOC_CHECK=t
 if test -z "$GIT_TEST_INSTALLED"; then
 	perf_results_prefix=
 else
+	if test -n "$GIT_PERF_DIR_MYDIR_REL"
+	then
+		GIT_TEST_INSTALLED=$GIT_PERF_DIR_MYDIR_REL
+	fi
 	perf_results_prefix=$(printf "%s" "${GIT_TEST_INSTALLED%/bin-wrappers}" | tr -c "[a-zA-Z0-9]" "[_*]")"."
 	GIT_TEST_INSTALLED=$ABSOLUTE_GIT_TEST_INSTALLED
 fi
diff --git a/t/perf/run b/t/perf/run
index 9aaa733c77..0a7c8744ab 100755
--- a/t/perf/run
+++ b/t/perf/run
@@ -91,10 +91,14 @@ run_dirs_helper () {
 	if test "$mydir" = .; then
 		unset GIT_TEST_INSTALLED
 	else
-		GIT_TEST_INSTALLED="$mydir/bin-wrappers"
+		GIT_PERF_DIR_MYDIR_REL=$mydir
+		GIT_PERF_DIR_MYDIR_ABS=$(cd $mydir && pwd)
+		export GIT_PERF_DIR_MYDIR_REL GIT_PERF_DIR_MYDIR_ABS
+
+		GIT_TEST_INSTALLED="$GIT_PERF_DIR_MYDIR_ABS/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
+		test -d "$GIT_TEST_INSTALLED" || GIT_TEST_INSTALLED=$GIT_PERF_DIR_MYDIR_ABS
 		export GIT_TEST_INSTALLED
 	fi
 	run_one_dir "$@"

-- 
2.21.0.593.g511ec345e18