# HG changeset patch
# User Martin von Zweigbergk <martinvonz@google.com>
# Date 1543428770 28800
# Node ID 2f14d1bbc9a7a142b421285c0708320b46be7a56
# Parent  c85964d715fd6e47faa66fb4b9d944622fa953c3
match: remove obsolete catching of OverflowError

Since 0f6a1bdf89fb (match: handle large regexes, 2007-08-19), we catch
an OverflowError from the regex engine and split up the regex if that
happens. In 59a9dc9562e2 (ignore: split up huge patterns, 2008-02-11),
that was extended to raise an OverflowError in our code even if the
regex engine doesn't raise it. It's unclear if there was a range of
regex sizes where the OverflowError would be raised from the regex
engine but that were still below the limit we added in our
code. Either way, both limitations were probably removed in Python
2.7.4 when the regex code width was extended from 16bit to 32bit (or
Py_UCS4) integer (thanks to Yuya for finding that out).

If at least the first limitation was removed, we no longer should be
using OverflowError for flow control, so this patch changes that.

Differential Revision: https://phab.mercurial-scm.org/D5309

diff -r c85964d715fd -r 2f14d1bbc9a7 mercurial/match.py
--- a/mercurial/match.py	Tue Nov 27 02:10:14 2018 +0100
+++ b/mercurial/match.py	Wed Nov 28 10:12:50 2018 -0800
@@ -1190,16 +1190,15 @@
     try:
         regex = '(?:%s)' % '|'.join([_regex(k, p, globsuffix)
                                      for (k, p, s) in kindpats])
-        if len(regex) > 20000:
-            raise OverflowError
-        return regex, _rematcher(regex)
-    except OverflowError:
+        if len(regex) <= 20000:
+            return regex, _rematcher(regex)
         # We're using a Python with a tiny regex engine and we
         # made it explode, so we'll divide the pattern list in two
         # until it works
         l = len(kindpats)
         if l < 2:
-            raise
+            # TODO: raise error.Abort here
+            raise OverflowError
         regexa, a = _buildregexmatch(kindpats[:l//2], globsuffix)
         regexb, b = _buildregexmatch(kindpats[l//2:], globsuffix)
         return regex, lambda s: a(s) or b(s)