t: allow overriding build dir

Our "test-lib.sh" assumes that our build directory is the parent
directory of "t/". While true when using our Makefile, it's not when
using build systems that support out-of-tree builds.

In commit ee9e66e4e7 (cmake: avoid editing t/test-lib.sh, 2022-10-18),
we have introduce support for overriding the GIT_BUILD_DIR by creating
the file "$GIT_BUILD_DIR/GIT-BUILD-DIR" with its contents pointing to
the location of the build directory. The intent was to stop modifying
"t/test-lib.sh" with the CMake build systems while allowing out-of-tree
builds. But "$GIT_BUILD_DIR" is somewhat misleadingly named, as it in
fact points to the _source_ directory. So while that commit solved part
of the problem for out-of-tree builds, CMake still has to write files
into the source tree.

Solve the second part of the problem, namely not having to write any
data into the source directory at all, by also supporting an environment
variable that allows us to point to a different build directory. This
allows us to perform properly self-contained out-of-tree builds.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/test-lib.sh b/t/test-lib.sh
index fe688a3fce7a7bbbe92bf721ee483cabd87e4654..62dfcc4aaf959d0cf066d07663d939e14f92485c 100644 (file)
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -35,7 +35,7 @@ else
        # needing to exist.
        TEST_DIRECTORY=$(cd "$TEST_DIRECTORY" && pwd) || exit 1
 fi
-GIT_BUILD_DIR="${TEST_DIRECTORY%/t}"
+GIT_BUILD_DIR="${GIT_BUILD_DIR:-${TEST_DIRECTORY%/t}}"
 if test "$TEST_DIRECTORY" = "$GIT_BUILD_DIR"
 then
        echo "PANIC: Running in a $TEST_DIRECTORY that doesn't end in '/t'?" >&2
@@ -522,6 +522,7 @@ unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e '
                PERF_
                CURL_VERBOSE
                TRACE_CURL
+               BUILD_DIR
        ));
        my @vars = grep(/^GIT_/ && !/^GIT_($ok)/o, @env);
        print join("\n", @vars);