[lldb] Fix issue with re.Pattern availability

[kastiglione]

Summary

re.Pattern is introduced in Python 3.7. To support Python 3.6, fallback to typechecking against SRE_Pattern.

[kastiglione]

Simplify the fallback expression.

[rastogishubham]

LGTM!

[mib]

LGTM! Anyway to test this ?

[kastiglione]

Anyway to test this ?

I don't have a Python 3.6 to test with. I did test locally which caught an issue, so I am at least confident it won't regress anything.

[kastiglione]

Use short circuit to avoid eager eval of re.SRE_Pattern

[kastiglione]

Switch to getting the type dynamically instead of by name.

[JDevlieghere]

LGTM

lldb/packages/Python/lldbsuite/test/decorators.py

if expected is None:
         return True
 
     if actual is None :
         return False
 
     if isinstance(expected, no_match):
         return not _match_decorator_property(expected.item, actual)
 
-    if isinstance(expected, (re.Pattern, str)):
+    # Python 3.6 doesn't declare a `re.Pattern` type, get the dynamic type.
+    pattern_type = type(re.compile(''))
+    if isinstance(expected, (pattern_type, str)):
         return re.search(expected, actual) is not None
 
     if hasattr(expected, "__iter__"):
         return any([x is not None and _match_decorator_property(x, actual)
                     for x in expected])
 
     return expected == actual
 

lldb/packages/Python/lldbsuite/test/lldbtest.py

def check_value(self, test_base, val, error_msg=None):
         not errors in the child values).
         """
 
         this_error_msg = error_msg if error_msg else ""
         this_error_msg += "\nChecking SBValue: " + str(val)
 
         test_base.assertSuccess(val.GetError())
 
+        # Python 3.6 doesn't declare a `re.Pattern` type, get the dynamic type.
+        pattern_type = type(re.compile(''))
+
         if self.expect_name:
             test_base.assertEqual(self.expect_name, val.GetName(),
                                   this_error_msg)
         if self.expect_value:
-            if isinstance(self.expect_value, re.Pattern):
+            if isinstance(self.expect_value, pattern_type):
                 test_base.assertRegex(val.GetValue(), self.expect_value,
                                       this_error_msg)
             else:
                 test_base.assertEqual(self.expect_value, val.GetValue(),
                                       this_error_msg)
         if self.expect_type:
             test_base.assertEqual(self.expect_type, val.GetDisplayTypeName(),
                                   this_error_msg)
         if self.expect_summary:
-            if isinstance(self.expect_summary, re.Pattern):
+            if isinstance(self.expect_summary, pattern_type):
                 test_base.assertRegex(val.GetSummary(), self.expect_summary,
                                       this_error_msg)
             else:
                 test_base.assertEqual(self.expect_summary, val.GetSummary(),
                                       this_error_msg)
         if self.children is not None:
             self.check_value_children(test_base, val, error_msg)