[3.6] bpo-30298: Weaken the condition of deprecation warnings for inline modifiers...

Now allowed several subsequential inline modifiers at the start of the
pattern (e.g. '(?i)(?s)...').  In verbose mode whitespaces and comments
now are allowed before and between inline modifiers (e.g.
'(?x) (?i) (?s)...')..
(cherry picked from commit 305ccbe27ea5ba82fd2d8c32ec739f980e524330)

diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
index 6aa49c3bf6f8ed10ae27b05c8efa963d9b54552f..e1c749634b71fe79b35c7dc9eac61e9122b7ff26 100644 (file)
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -412,7 +412,7 @@ def _parse_sub(source, state, verbose, nested=True):
     sourcematch = source.match
     start = source.tell()
     while True:
-        itemsappend(_parse(source, state, verbose))
+        itemsappend(_parse(source, state, verbose, not nested and not items))
         if not sourcematch("|"):
             break
 
@@ -466,7 +466,7 @@ def _parse_sub_cond(source, state, condgroup, verbose):
     subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
     return subpattern
 
-def _parse(source, state, verbose):
+def _parse(source, state, verbose, first=False):
     # parse a simple pattern
     subpattern = SubPattern(state)
 
@@ -730,10 +730,9 @@ def _parse(source, state, verbose):
                     state.checklookbehindgroup(condgroup, source)
                 elif char in FLAGS or char == "-":
                     # flags
-                    pos = source.pos
                     flags = _parse_flags(source, state, char)
                     if flags is None:  # global flags
-                        if pos != 3:  # "(?x"
+                        if not first or subpattern:
                             import warnings
                             warnings.warn(
                                 'Flags not at the start of the expression %s%s' % (
@@ -742,6 +741,8 @@ def _parse(source, state, verbose):
                                 ),
                                 DeprecationWarning, stacklevel=7
                             )
+                        if (state.flags & SRE_FLAG_VERBOSE) and not verbose:
+                            raise Verbose
                         continue
                     add_flags, del_flags = flags
                     group = None
@@ -795,9 +796,6 @@ def _parse_flags(source, state, char):
                 msg = "unknown flag" if char.isalpha() else "missing -, : or )"
                 raise source.error(msg, len(char))
     if char == ")":
-        if ((add_flags & SRE_FLAG_VERBOSE) and
-            not (state.flags & SRE_FLAG_VERBOSE)):
-            raise Verbose
         state.flags |= add_flags
         return None
     if add_flags & GLOBAL_FLAGS:

diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index b945cf094e99c17df81835e9f03196ada32b569d..c52417ba000ebca8d3c1cf23f682e909f0887d9b 100644 (file)
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -1303,32 +1303,43 @@ class ReTests(unittest.TestCase):
         upper_char = '\u1ea0' # Latin Capital Letter A with Dot Below
         lower_char = '\u1ea1' # Latin Small Letter A with Dot Below
 
-        p = re.compile(upper_char, re.I | re.U)
-        q = p.match(lower_char)
+        p = re.compile('.' + upper_char, re.I | re.S)
+        q = p.match('\n' + lower_char)
         self.assertTrue(q)
 
-        p = re.compile(lower_char, re.I | re.U)
-        q = p.match(upper_char)
+        p = re.compile('.' + lower_char, re.I | re.S)
+        q = p.match('\n' + upper_char)
         self.assertTrue(q)
 
-        p = re.compile('(?i)' + upper_char, re.U)
-        q = p.match(lower_char)
+        p = re.compile('(?i).' + upper_char, re.S)
+        q = p.match('\n' + lower_char)
         self.assertTrue(q)
 
-        p = re.compile('(?i)' + lower_char, re.U)
-        q = p.match(upper_char)
+        p = re.compile('(?i).' + lower_char, re.S)
+        q = p.match('\n' + upper_char)
         self.assertTrue(q)
 
-        p = re.compile('(?iu)' + upper_char)
-        q = p.match(lower_char)
+        p = re.compile('(?is).' + upper_char)
+        q = p.match('\n' + lower_char)
         self.assertTrue(q)
 
-        p = re.compile('(?iu)' + lower_char)
-        q = p.match(upper_char)
+        p = re.compile('(?is).' + lower_char)
+        q = p.match('\n' + upper_char)
         self.assertTrue(q)
 
-        self.assertTrue(re.match('(?ixu) ' + upper_char, lower_char))
-        self.assertTrue(re.match('(?ixu) ' + lower_char, upper_char))
+        p = re.compile('(?s)(?i).' + upper_char)
+        q = p.match('\n' + lower_char)
+        self.assertTrue(q)
+
+        p = re.compile('(?s)(?i).' + lower_char)
+        q = p.match('\n' + upper_char)
+        self.assertTrue(q)
+
+        self.assertTrue(re.match('(?ix) ' + upper_char, lower_char))
+        self.assertTrue(re.match('(?ix) ' + lower_char, upper_char))
+        self.assertTrue(re.match(' (?i) ' + upper_char, lower_char, re.X))
+        self.assertTrue(re.match('(?x) (?i) ' + upper_char, lower_char))
+        self.assertTrue(re.match(' (?x) (?i) ' + upper_char, lower_char, re.X))
 
         p = upper_char + '(?i)'
         with self.assertWarns(DeprecationWarning) as warns:
@@ -1346,6 +1357,26 @@ class ReTests(unittest.TestCase):
             'Flags not at the start of the expression %s (truncated)' % p[:20]
         )
 
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.match('(?s).(?i)' + upper_char, '\n' + lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.match('(?i) ' + upper_char + ' (?x)', lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.match(' (?x) (?i) ' + upper_char, lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.match('^(?i)' + upper_char, lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.match('$|(?i)' + upper_char, lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.match('(?:(?i)' + upper_char + ')', lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.fullmatch('(^)?(?(1)(?i)' + upper_char + ')',
+                                         lower_char))
+        with self.assertWarns(DeprecationWarning):
+            self.assertTrue(re.fullmatch('($)?(?(1)|(?i)' + upper_char + ')',
+                                         lower_char))
+
+
     def test_dollar_matches_twice(self):
         "$ matches the end of string, and just before the terminating \n"
         pattern = re.compile('$')

diff --git a/Misc/NEWS b/Misc/NEWS
index 64974ef2eb2260a35a59a6745728833594a99b9a..e7090fc17840abd21bc26e118480edbe85615c56 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -36,6 +36,12 @@ Core and Builtins
 Library
 -------
 
+- bpo-30298: Weaken the condition of deprecation warnings for inline modifiers.
+  Now allowed several subsequential inline modifiers at the start of the
+  pattern (e.g. ``'(?i)(?s)...'``).  In verbose mode whitespaces and comments
+  now are allowed before and between inline modifiers (e.g.
+  ``'(?x) (?i) (?s)...'``).
+
 - bpo-29990: Fix range checking in GB18030 decoder.  Original patch by Ma Lin.
 
 - Revert bpo-26293 for zipfile breakage. See also bpo-29094.