Merge branch 'ab/test-leak-diag'

Random test-framework clean-up.

* ab/test-leak-diag:
  test-lib: add "fast_unwind_on_malloc=0" to LSAN_OPTIONS
  test-lib: make $GIT_BUILD_DIR an absolute path
  test-lib: correct and assert TEST_DIRECTORY overriding
  test-lib: add GIT_SAN_OPTIONS, inherit [AL]SAN_OPTIONS

Author: gitster

t/test-lib.sh

@@ -19,13 +19,20 @@
 # t/ subdirectory and are run in 'trash directory' subdirectory.
 if test -z "$TEST_DIRECTORY"
 then
-	# We allow tests to override this, in case they want to run tests
-	# outside of t/, e.g. for running tests on the test library
-	# itself.
-	TEST_DIRECTORY=$(pwd)
-else
 	# ensure that TEST_DIRECTORY is an absolute path so that it
 	# is valid even if the current working directory is changed
+	TEST_DIRECTORY=$(pwd)
+else
+	# The TEST_DIRECTORY will always be the path to the "t"
+	# directory in the git.git checkout. This is overridden by
+	# e.g. t/lib-subtest.sh, but only because its $(pwd) is
+	# different. Those tests still set "$TEST_DIRECTORY" to the
+	# same path.
+	#
+	# See use of "$GIT_BUILD_DIR" and "$TEST_DIRECTORY" below for
+	# hard assumptions about "$GIT_BUILD_DIR/t" existing and being
+	# the "$TEST_DIRECTORY", and e.g. "$TEST_DIRECTORY/helper"
+	# needing to exist.
 	TEST_DIRECTORY=$(cd "$TEST_DIRECTORY" && pwd) || exit 1
 fi
 if test -z "$TEST_OUTPUT_DIRECTORY"
@@ -34,19 +41,42 @@ then
 	# elsewhere
 	TEST_OUTPUT_DIRECTORY=$TEST_DIRECTORY
 fi
-GIT_BUILD_DIR="$TEST_DIRECTORY"/..
+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
+	exit 1
+fi
+
+# Prepend a string to a VAR using an arbitrary ":" delimiter, not
+# adding the delimiter if VAR or VALUE is empty. I.e. a generalized:
+#
+#	VAR=$1${VAR:+${1:+$2}$VAR}
+#
+# Usage (using ":" as the $2 delimiter):
+#
+#	prepend_var VAR : VALUE
+prepend_var () {
+	eval "$1=$3\${$1:+${3:+$2}\$$1}"
+}
+
+# If [AL]SAN is in effect we want to abort so that we notice
+# problems. The GIT_SAN_OPTIONS variable can be used to set common
+# defaults shared between [AL]SAN_OPTIONS.
+prepend_var GIT_SAN_OPTIONS : abort_on_error=1
+prepend_var GIT_SAN_OPTIONS : strip_path_prefix=\"$GIT_BUILD_DIR/\"
 
 # If we were built with ASAN, it may complain about leaks
 # of program-lifetime variables. Disable it by default to lower
 # the noise level. This needs to happen at the start of the script,
 # before we even do our "did we build git yet" check (since we don't
 # want that one to complain to stderr).
-: ${ASAN_OPTIONS=detect_leaks=0:abort_on_error=1}
+prepend_var ASAN_OPTIONS : $GIT_SAN_OPTIONS
+prepend_var ASAN_OPTIONS : detect_leaks=0
 export ASAN_OPTIONS
 
-# If LSAN is in effect we _do_ want leak checking, but we still
-# want to abort so that we notice the problems.
-: ${LSAN_OPTIONS=abort_on_error=1}
+prepend_var LSAN_OPTIONS : $GIT_SAN_OPTIONS
+prepend_var LSAN_OPTIONS : fast_unwind_on_malloc=0
 export LSAN_OPTIONS
 
 if test ! -f "$GIT_BUILD_DIR"/GIT-BUILD-OPTIONS