From dfc507e800a3da6275bc5a2ebf4ac56c9af79b7b Mon Sep 17 00:00:00 2001
From: mdipierro <massimo.dipierro@gmail.com>
Date: Tue, 3 Apr 2018 11:55:46 -0500
Subject: [PATCH] better handling of redefine and lazy tables thanks Paolo
 Pastori

---
 pydal/base.py    | 37 ++++++++++++++++++++-----------------
 pydal/objects.py |  8 ++++----
 2 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/pydal/base.py b/pydal/base.py
index 803d44182..7d2b724d5 100644
--- a/pydal/base.py
+++ b/pydal/base.py
@@ -154,7 +154,7 @@
 
 class MetaDAL(type):
     def __call__(cls, *args, **kwargs):
-        #: intercept arguments for DAL costumisation on call
+        #: intercept arguments for DAL customisation on call
         intercepts = [
             'logger', 'representers', 'serializers', 'uuid', 'validators',
             'validators_method', 'Table', 'Row']
@@ -484,8 +484,7 @@ def __init__(self, uri='sqlite://dummy.db',
             self.validators = None
         adapter = self._adapter
         self._uri_hash = table_hash or hashlib_md5(adapter.uri).hexdigest()
-        self.check_reserved = check_reserved
-        if self.check_reserved:
+        if check_reserved:
             from .contrib.reserved_sql_keywords import ADAPTERS as RSK
             self.RSK = RSK
         self._migrate = migrate
@@ -542,9 +541,9 @@ def import_table_definitions(self, path, migrate=False,
     def check_reserved_keyword(self, name):
         """
         Validates `name` against SQL keywords
-        Uses self.check_reserve which is a list of operators to use.
+        Uses self._check_reserved which is a list of operators to use.
         """
-        for backend in self.check_reserved:
+        for backend in self._check_reserved:
             if name.upper() in self.RSK[backend]:
                 raise SyntaxError(
                     'invalid table/column name "%s" is a "%s" reserved SQL/NOSQL keyword' % (name, backend.upper()))
@@ -555,6 +554,10 @@ def parse_as_rest(self, patterns, args, vars, queries=None,
             patterns, args, vars, queries, nested_select)
 
     def define_table(self, tablename, *fields, **kwargs):
+        invalid_kwargs = set(kwargs) - TABLE_ARGS
+        if invalid_kwargs:
+            raise SyntaxError('invalid table "%s" attributes: %s' %
+                              (tablename, invalid_kwargs))
         if not fields and 'fields' in kwargs:
             fields = kwargs.get('fields',())
         if not isinstance(tablename, str):
@@ -565,23 +568,23 @@ def define_table(self, tablename, *fields, **kwargs):
                     raise SyntaxError("invalid unicode table name")
             else:
                 raise SyntaxError("missing table name")
-        elif hasattr(self, tablename) or tablename in self.tables:
-            if kwargs.get('redefine', False):
-                delattr(self, tablename)
+        redefine = kwargs.get('redefine', False)
+        if tablename in self.tables:
+            if redefine:
+                try:
+                    delattr(self, tablename)
+                except:
+                    pass
             else:
                 raise SyntaxError('table already defined: %s' % tablename)
-        elif tablename.startswith('_') or hasattr(self, tablename) or \
+        elif tablename.startswith('_') or tablename in dir(self) or \
                 REGEX_PYTHON_KEYWORDS.match(tablename):
             raise SyntaxError('invalid table name: %s' % tablename)
-        elif self.check_reserved:
+        elif self._check_reserved:
             self.check_reserved_keyword(tablename)
-        else:
-            invalid_kwargs = set(kwargs) - TABLE_ARGS
-            if invalid_kwargs:
-                raise SyntaxError('invalid table "%s" attributes: %s' %
-                                  (tablename, invalid_kwargs))
-        if self._lazy_tables and tablename not in self._LAZY_TABLES:
-            self._LAZY_TABLES[tablename] = (tablename, fields, kwargs)
+        if self._lazy_tables:
+            if tablename not in self._LAZY_TABLES or redefine:
+                self._LAZY_TABLES[tablename] = (tablename, fields, kwargs)
             table = None
         else:
             table = self.lazy_define_table(tablename, *fields, **kwargs)
diff --git a/pydal/objects.py b/pydal/objects.py
index 452ed7b4f..f4415fbad 100644
--- a/pydal/objects.py
+++ b/pydal/objects.py
@@ -337,15 +337,15 @@ def include_new(field):
 
         fieldnames_set = set()
         reserved = dir(Table) + ['fields']
-        if (db and db.check_reserved):
-            check_reserved = db.check_reserved_keyword
+        if (db and db._check_reserved):
+            check_reserved_keyword = db.check_reserved_keyword
         else:
-            def check_reserved(field_name):
+            def check_reserved_keyword(field_name):
                 if field_name in reserved:
                     raise SyntaxError("field name %s not allowed" % field_name)
         for field in fields:
             field_name = field.name
-            check_reserved(field_name)
+            check_reserved_keyword(field_name)
             if db and db._ignore_field_case:
                 fname_item = field_name.lower()
             else: