diff --git a/Lib/re.py b/Lib/re.py index d0ee5db175b5fa..657a4f6721ed59 100644 --- a/Lib/re.py +++ b/Lib/re.py @@ -128,6 +128,13 @@ except ImportError: _locale = None +# try _collections first to reduce startup cost +try: + from _collections import OrderedDict +except ImportError: + from collections import OrderedDict + + # public symbols __all__ = [ "match", "fullmatch", "search", "sub", "subn", "split", @@ -260,7 +267,7 @@ def escape(pattern): # -------------------------------------------------------------------- # internals -_cache = {} +_cache = OrderedDict() _pattern_type = type(sre_compile.compile("", 0)) @@ -281,7 +288,10 @@ def _compile(pattern, flags): p = sre_compile.compile(pattern, flags) if not (flags & DEBUG): if len(_cache) >= _MAXCACHE: - _cache.clear() + try: + _cache.popitem(False) + except KeyError: + pass _cache[type(pattern), pattern, flags] = p return p diff --git a/Misc/NEWS.d/next/Library/2017-09-26-17-51-17.bpo-28293.UC5pm4.rst b/Misc/NEWS.d/next/Library/2017-09-26-17-51-17.bpo-28293.UC5pm4.rst new file mode 100644 index 00000000000000..16b92b05dbf630 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2017-09-26-17-51-17.bpo-28293.UC5pm4.rst @@ -0,0 +1 @@ +The regular expression cache is no longer completely dumped when it is full.