Issue #20426: When passing the re.DEBUG flag, re.compile() displays the debug output every time it is called, regardless of the compilation cache.
diff --git a/Lib/re.py b/Lib/re.py
index aab5d37..9b01f3e 100644
--- a/Lib/re.py
+++ b/Lib/re.py
@@ -225,11 +225,13 @@
def _compile(*key):
# internal: compile pattern
- cachekey = (type(key[0]),) + key
- p = _cache.get(cachekey)
- if p is not None:
- return p
pattern, flags = key
+ bypass_cache = flags & DEBUG
+ if not bypass_cache:
+ cachekey = (type(key[0]),) + key
+ p = _cache.get(cachekey)
+ if p is not None:
+ return p
if isinstance(pattern, _pattern_type):
if flags:
raise ValueError('Cannot process flags argument with a compiled pattern')
@@ -240,9 +242,10 @@
p = sre_compile.compile(pattern, flags)
except error, v:
raise error, v # invalid expression
- if len(_cache) >= _MAXCACHE:
- _cache.clear()
- _cache[cachekey] = p
+ if not bypass_cache:
+ if len(_cache) >= _MAXCACHE:
+ _cache.clear()
+ _cache[cachekey] = p
return p
def _compile_repl(*key):
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 7ebbf05..fe71c84 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -1,5 +1,6 @@
from test.test_support import verbose, run_unittest, import_module
from test.test_support import precisionbigmemtest, _2G, cpython_only
+from test.test_support import captured_stdout
import re
from re import Scanner
import sre_constants
@@ -920,6 +921,19 @@
self.assertEqual(m.group(1), "")
self.assertEqual(m.group(2), "y")
+ def test_debug_flag(self):
+ with captured_stdout() as out:
+ re.compile('foo', re.DEBUG)
+ self.assertEqual(out.getvalue().splitlines(),
+ ['literal 102', 'literal 111', 'literal 111'])
+ # Debug output is output again even a second time (bypassing
+ # the cache -- issue #20426).
+ with captured_stdout() as out:
+ re.compile('foo', re.DEBUG)
+ self.assertEqual(out.getvalue().splitlines(),
+ ['literal 102', 'literal 111', 'literal 111'])
+
+
def run_re_tests():
from test.re_tests import tests, SUCCEED, FAIL, SYNTAX_ERROR
if verbose: