[cfl] Allow reporting of unreproducible crashes.

Fixes google/clusterfuzzlite#65

infra/cifuzz/config_utils.py

@@ -206,6 +206,8 @@ def __init__(self):
     if not os.getenv('CIFUZZ_TEST') and not self._run_config_validate():
       raise ConfigError('Invalid Run Configuration.')
 
+    self.report_old_crashes = environment.get_bool('REPORT_OLD_CRASHES', False)
+
   def _run_config_validate(self):
     """Do extra validation on RunFuzzersConfig.__init__(). Do not name this
     validate or else it will be called when using the parent's __init__ and will

infra/cifuzz/fuzz_target.py

@@ -303,7 +303,10 @@ def is_crash_reportable(self, testcase, reproduce_args, batch=False):
       # We don't need to check if the crash is novel for batch fuzzing.
       return True
 
-    return self.is_crash_novel(testcase, reproduce_args)
+    is_novel = self.is_crash_novel(testcase, reproduce_args)
+    if not is_novel:
+      return self.config.report_old_crashes
+    return True
 
   def is_crash_type_reportable(self, testcase):
     """Returns True if |testcase| is an actual crash. If crash is a timeout or

infra/cifuzz/fuzz_target_test.py

@@ -175,6 +175,24 @@ def test_new_reproducible_crash(self, mock_info, _):
         'The crash is not reproducible on previous build. '
         'Code change (pr/commit) introduced crash.')
 
+  @mock.patch('fuzz_target.FuzzTarget.is_reproducible', return_value=True)
+  @mock.patch('fuzz_target.FuzzTarget.is_crash_novel', return_value=False)
+  def test_old_reproducible_crash(self, _, __):
+    """Tests that an old reproducible crash returns False."""
+    with tempfile.TemporaryDirectory() as tmp_dir:
+      self.target.out_dir = tmp_dir
+      self.assertFalse(self.target.is_crash_reportable(self.testcase_path, []))
+
+  @mock.patch('fuzz_target.FuzzTarget.is_reproducible', return_value=True)
+  @mock.patch('fuzz_target.FuzzTarget.is_crash_novel', return_value=False)
+  def test_old_reproducible_crash_report_unreproducible(self, _, __):
+    """Tests that an old reproducible crash returns True if config to report old
+    crashes is True."""
+    with tempfile.TemporaryDirectory() as tmp_dir:
+      self.target.out_dir = tmp_dir
+      self.target.config.report_old_crashes = True
+      self.assertTrue(self.target.is_crash_reportable(self.testcase_path, []))
+
   # yapf: disable
   @parameterized.parameterized.expand([
       # Reproducible on PR build, but also reproducible on OSS-Fuzz.