[foozzie] Fix failure state for non-existing source output

tools/foozzie/v8_foozzie.py

 #!/usr/bin/env python
 # Copyright 2016 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 V8 correctness fuzzer launcher script.
 """
 
 import argparse
-import hashlib
 import itertools
 import json
 import os
 import re
 import sys
 import traceback
 
 import v8_commands
 import v8_suppressions
 
 CONFIGS = dict(
   default=[],
   validate_asm=['--validate-asm'], # Maybe add , '--disable-asm-warnings'
   fullcode=['--nocrankshaft', '--turbo-filter=~'],
   noturbo=['--turbo-filter=~', '--noturbo-asm'],
   noturbo_opt=['--always-opt', '--turbo-filter=~', '--noturbo-asm'],
   ignition_staging=['--ignition-staging'],
   ignition_turbo=['--ignition-staging', '--turbo'],
   ignition_turbo_opt=['--ignition-staging', '--turbo', '--always-opt'],
 )
 
 # Timeout in seconds for one d8 run.
 TIMEOUT = 3
 
 # Return codes.
 RETURN_PASS = 0
 RETURN_FAIL = 2
 
-# The number of hex digits used from the hash of the original source file path.
-# Keep the number small to avoid duplicate explosion.
-SOURCE_HASH_LENGTH = 3
-
 BASE_PATH = os.path.dirname(os.path.abspath(__file__))
 PREAMBLE = [
   os.path.join(BASE_PATH, 'v8_mock.js'),
   os.path.join(BASE_PATH, 'v8_suppressions.js'),
 ]
 
 FLAGS = ['--abort_on_stack_overflow', '--expose-gc', '--allow-natives-syntax',
          '--invoke-weak-callbacks', '--omit-quit', '--es-staging']
 
 SUPPORTED_ARCHS = ['ia32', 'x64', 'arm', 'arm64']
@@ skipping 187 matching lines @@
     return RETURN_FAIL
 
   second_config_output = run_d8(options.second_d8, second_config_flags)
 
   # Bailout based on second run's output.
   if pass_bailout(second_config_output, 2):
     return RETURN_PASS
   if fail_bailout(second_config_output, suppress.ignore_by_output2):
     return RETURN_FAIL
 
-  difference, source = suppress.diff(
+  difference, source_key = suppress.diff(
       first_config_output.stdout, second_config_output.stdout)
   if difference:
     # The first three entries will be parsed by clusterfuzz. Format changes
     # will require changes on the clusterfuzz side.
     first_config_label = '%s,%s' % (options.first_arch, options.first_config)
     second_config_label = '%s,%s' % (options.second_arch, options.second_config)
     print FAILURE_TEMPLATE % dict(
         configs='%s:%s' % (first_config_label, second_config_label),
-        sources=hashlib.sha1(source).hexdigest()[:SOURCE_HASH_LENGTH],
+        sources=source_key,
         suppression='', # We can't tie bugs to differences.
         first_config_label=first_config_label,
         second_config_label=second_config_label,
         first_config_flags=' '.join(first_config_flags),
         second_config_flags=' '.join(second_config_flags),
         first_config_output=first_config_output.stdout,
         second_config_output=second_config_output.stdout,
         difference=difference,
     )
     return RETURN_FAIL
@@ skipping 16 matching lines @@
         configs='', sources='', suppression='wrong_usage')
     result = RETURN_FAIL
   except Exception as e:
     print FAILURE_HEADER_TEMPLATE % dict(
         configs='', sources='', suppression='internal_error')
     print '# Internal error: %s' % e
     traceback.print_exc(file=sys.stdout)
     result = RETURN_FAIL
 
   sys.exit(result)