[Python-checkins] cpython (merge 3.3 -> default): Issue #20426: When passing the re.DEBUG flag, re.compile() displays the debug

Mon Feb 3 21:01:54 CET 2014

http://hg.python.org/cpython/rev/a8bcfa290e68
changeset: 88941:a8bcfa290e68
parent: 88939:6007e81f5867
parent: 88940:a7b180d5df5f
user: Antoine Pitrou <solipsis at pitrou.net>
date: Mon Feb 03 21:01:35 2014 +0100
summary:
 Issue #20426: When passing the re.DEBUG flag, re.compile() displays the debug output every time it is called, regardless of the compilation cache.
files:
 Lib/re.py | 17 ++++++++++-------
 Lib/test/test_re.py | 14 +++++++++++++-
 Misc/NEWS | 3 +++
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/Lib/re.py b/Lib/re.py
--- a/Lib/re.py
+++ b/Lib/re.py
@@ -272,10 +272,12 @@
 _MAXCACHE = 512
 def _compile(pattern, flags):
 # internal: compile pattern
- try:
- return _cache[type(pattern), pattern, flags]
- except KeyError:
- pass
+ bypass_cache = flags & DEBUG
+ if not bypass_cache:
+ try:
+ return _cache[type(pattern), pattern, flags]
+ except KeyError:
+ pass
 if isinstance(pattern, _pattern_type):
 if flags:
 raise ValueError(
@@ -284,9 +286,10 @@
 if not sre_compile.isstring(pattern):
 raise TypeError("first argument must be string or compiled pattern")
 p = sre_compile.compile(pattern, flags)
- if len(_cache) >= _MAXCACHE:
- _cache.clear()
- _cache[type(pattern), pattern, flags] = p
+ if not bypass_cache:
+ if len(_cache) >= _MAXCACHE:
+ _cache.clear()
+ _cache[type(pattern), pattern, flags] = p
 return p
 
 def _compile_repl(repl, pattern):
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -1,5 +1,5 @@
 from test.support import verbose, run_unittest, gc_collect, bigmemtest, _2G, \
- cpython_only
+ cpython_only, captured_stdout
 import io
 import re
 from re import Scanner
@@ -1193,6 +1193,18 @@
 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 '])
+
 
 class PatternReprTests(unittest.TestCase):
 def check(self, pattern, expected):
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -16,6 +16,9 @@
 Library
 -------
 
+- Issue #20426: When passing the re.DEBUG flag, re.compile() displays the
+ debug output every time it is called, regardless of the compilation cache.
+
 - Issue #20368: The null character now correctly passed from Tcl to Python.
 Improved error handling in variables-related commands.
 
-- 
Repository URL: http://hg.python.org/cpython
