[3.6] bpo-30298: Weaken the condition of deprecation warnings for inline modifiers. (GH-1490) (#1525)

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)

1 files changed, 45 insertions, 14 deletions

diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index b945cf0..c52417b 100644
--- 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('$')