stringutil: add a new function to do minimal regex escaping
Per https://bugs.python.org/
issue29995, re.escape() used to
over-escape regular expression strings, but in Python 3.7 that's been
fixed, which also improved the performance of re.escape(). Since it's
both an output change for us *and* a perfomance win, let's just
effectively backport the new behavior to hg on all Python versions.
Differential Revision: https://phab.mercurial-scm.org/D3841
--- a/mercurial/utils/stringutil.py Tue Jun 26 16:14:02 2018 +0530
+++ b/mercurial/utils/stringutil.py Tue Jun 26 10:33:52 2018 -0400
@@ -23,6 +23,25 @@
pycompat,
)
+# regex special chars pulled from https://bugs.python.org/issue29995
+# which was part of Python 3.7.
+_respecial = pycompat.bytestr(b'()[]{}?*+-|^$\\.# \t\n\r\v\f')
+_regexescapemap = {ord(i): (b'\\' + i).decode('latin1') for i in _respecial}
+
+def reescape(pat):
+ """Drop-in replacement for re.escape."""
+ # NOTE: it is intentional that this works on unicodes and not
+ # bytes, as it's only possible to do the escaping with
+ # unicode.translate, not bytes.translate. Sigh.
+ wantuni = True
+ if isinstance(pat, bytes):
+ wantuni = False
+ pat = pat.decode('latin1')
+ pat = pat.translate(_regexescapemap)
+ if wantuni:
+ return pat
+ return pat.encode('latin1')
+
def pprint(o, bprefix=False):
"""Pretty print an object."""
if isinstance(o, bytes):