t/perf: fix regression in testing older versions of git

Commit 7501b59 (perf: make the tests work in worktrees,
2016-05-13) introduced the use of "git rev-parse --git-path"
in the perf-lib setup code. Because the to-be-tested version
of git is at the front of the $PATH when this code runs,
this means we cannot use modern versions of t/perf to test
versions of git older than v2.5.0 (when that option was
introduced).

This is a symptom of a more general problem. The t/perf
suite is essentially independent of git versions, and
ideally we would be able to run the most modern and complete
set of tests across many historical versions (to see how
they compare). But any setup code they run is therefore
required to use the lowest common denominator we expect to
test.

So let's introduce a new variable, $MODERN_GIT, that we can
use both in perf-lib and in the test setup to get a reliable
set of git features (we might change git and break some
tests, of course, but $MODERN_GIT is tied to the same
version of git as the t/perf scripts, so they can be fixed
or adjusted together).

This commit fixes the "--git-path" case, but does not
mass-convert existing setup code to use $MODERN_GIT. Most
setup code is fairly vanilla and will work with effectively
all versions. But now the tool is there to fix any other
issues we find going forward.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2016-06-22 15:40:13 -04:00 committed by Junio C Hamano
parent 7501b59210
commit 1a0962dee5
2 changed files with 14 additions and 3 deletions

View file

@ -115,8 +115,16 @@ After that you will want to use some of the following:
At least one of the first two is required!
You can use test_expect_success as usual. For actual performance
tests, use
You can use test_expect_success as usual. In both test_expect_success
and in test_perf, running "git" points to the version that is being
perf-tested. The $MODERN_GIT variable points to the git wrapper for the
currently checked-out version (i.e., the one that matches the t/perf
scripts you are running). This is useful if your setup uses commands
that only work with newer versions of git than what you might want to
test (but obviously your new commands must still create a state that can
be used by the older version of git you are testing).
For actual performance tests, use
test_perf 'descriptive string' '
command1 &&

View file

@ -52,6 +52,9 @@ TEST_NO_MALLOC_CHECK=t
# need to export them for test_perf subshells
export TEST_DIRECTORY TRASH_DIRECTORY GIT_BUILD_DIR GIT_TEST_CMP
MODERN_GIT=$GIT_BUILD_DIR/bin-wrappers/git
export MODERN_GIT
perf_results_dir=$TEST_OUTPUT_DIRECTORY/test-results
mkdir -p "$perf_results_dir"
rm -f "$perf_results_dir"/$(basename "$0" .sh).subtests
@ -81,7 +84,7 @@ test_perf_create_repo_from () {
repo="$1"
source="$2"
source_git="$(git -C "$source" rev-parse --git-dir)"
objects_dir="$(git -C "$source" rev-parse --git-path objects)"
objects_dir="$("$MODERN_GIT" -C "$source" rev-parse --git-path objects)"
mkdir -p "$repo/.git"
(
{ cp -Rl "$objects_dir" "$repo/.git/" 2>/dev/null ||