tests: pcre-jitstack: upon failure, retry with no stack size limit

* tests/pcre-jitstack: Don't let an example that provokes inordinate
stack space use cause a test failure.  Thanks to reports from and
analysis by Bruce Dubbs; see http://debbugs.gnu.org/21755

1 files changed, 14 insertions, 1 deletions

diff --git a/tests/pcre-jitstack b/tests/pcre-jitstack
index 03587f1a..d9a56158 100755
--- a/tests/pcre-jitstack
+++ b/tests/pcre-jitstack
@@ -34,6 +34,19 @@ test $? -eq 0 || framework_failure_
 gzip -d pcrejit.txt || framework_failure_
 
 LC_ALL=C grep -P -n '^([/](?!/)|[^/])*~/.*' pcrejit.txt
-test $? -eq 1 || fail=1
+if test $? != 1; then
+    # The above often makes grep attempt to use an inordinate amount
+    # of stack space.  If grep fails with $? != 1, try gain, but this
+    # time with no soft limit:
+
+    # Use ulimit to remove that limit, if possible.
+    # If ulimit is not usable, just skip this test.
+    (ulimit -s unlimited; : ) || skip_ this shell lacks ulimit support
+
+    # Rerun that same test, but now with no limit on stack size:
+    (ulimit -s unlimited;
+     LC_ALL=C grep -P -n '^([/](?!/)|[^/])*~/.*' pcrejit.txt)
+    test $? = 1 || fail=1
+fi
 
 Exit $fail