Table.from_table: refactor: separate cache-independent part

Author: markotoplak

Orange/data/table.py

@@ -792,6 +792,16 @@ def from_table(cls, domain, source, row_indices=...):
         :return: a new table
         :rtype: Orange.data.Table
         """
+        if domain is source.domain:
+            table = cls.from_table_rows(source, row_indices)
+            # assure resulting domain is the instance passed on input
+            table.domain = domain
+            # since sparse flags are not considered when checking for
+            # domain equality, fix manually.
+            with table.unlocked_reference():
+                table = assure_domain_conversion_sparsity(table, source)
+            return table
+
         new_cache = _thread_local.conversion_cache is None
         try:
             if new_cache:
@@ -801,17 +811,6 @@ def from_table(cls, domain, source, row_indices=...):
                 cached = _idcache_restore(_thread_local.conversion_cache, (domain, source))
                 if cached is not None:
                     return cached
-            if domain is source.domain:
-                table = cls.from_table_rows(source, row_indices)
-                # assure resulting domain is the instance passed on input
-                table.domain = domain
-                # since sparse flags are not considered when checking for
-                # domain equality, fix manually.
-                with table.unlocked_reference():
-                    table = assure_domain_conversion_sparsity(table, source)
-                if new_cache:  # from_table_rows is not outermost: explicitly deepcopy attributes
-                    table.attributes = deepcopy(getattr(source, 'attributes', {}))
-                return table
 
             # avoid boolean indices; also convert to slices if possible
             row_indices = _optimize_indices(row_indices, len(source))