Failing test and XXX code comment about a bug used to test this bug.

bin/pt-query-digest

@@ -13239,6 +13239,11 @@ sub print_reports {
       );
 
       if ( $o->get('report') ) {
+         # XXX There's a bug here: --expected-range '','' will cause
+         # Use of uninitialized value in numeric lt (<)
+         # This bug is intentionally left unfixed at the moment because
+         # we exploit it to test a more serious bug: an infinite loop:
+         # https://bugs.launchpad.net/percona-toolkit/+bug/888114
          my $expected_range = $o->get('expected-range');
          my $explain_why    = $expected_range
                             && (   @$worst < $expected_range->[0]

t/pt-query-digest/continue_on_error.t

@@ -9,9 +9,12 @@ BEGIN {
 use strict;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
-use Test::More tests => 2;
+use Test::More tests => 3;
 
 use PerconaTest;
+shift @INC;  # our unshift (above)
+shift @INC;  # PerconaTest's unshift
+require "$trunk/bin/pt-query-digest";
 
 my $output;
 
@@ -30,6 +33,25 @@ like(
    'Continues on error by default'
 );
 
+# #############################################################################
+# Infinite loop in pt-query-digest if a report crashe
+# https://bugs.launchpad.net/percona-toolkit/+bug/888114
+# #############################################################################
+
+# This bug is due to the fact that --continue-on-error is on by default.
+# To reproduce the problem, we must intentionally crash pt-query-digest
+# in the right place, which means we're using another bug:a
+$output = output(
+   sub { pt_query_digest::main("$trunk/t/lib/samples/slowlogs/slow002.txt",
+      "--expected-range", "'',''") },
+   stderr => 1,
+);
+
+like(
+   $output,
+   qr/Query\s+1/,
+   "No infinite loop in report crashes (bug 888114)"
+);
 
 # #############################################################################
 # Done.