BUG/INT: Internal tests for patching __finalize__ / bug in concat not finalizing (GH6927)

doc/source/release.rst

@@ -396,7 +396,7 @@ Bug Fixes
 - Bug in ``DataFrame.to_csv`` where setting `index` to `False` ignored the
   `header` kwarg (:issue:`6186`)
 - Bug in `DataFrame.plot` and `Series.plot` legend behave inconsistently when plotting to the same axes repeatedly (:issue:`6678`)
-- Internal tests for patching ``__finalize__`` / bug in merge not finalizing (:issue:`6923`)
+- Internal tests for patching ``__finalize__`` / bug in merge not finalizing (:issue:`6923`, :issue:`6927`)
 
 pandas 0.13.1
 -------------

pandas/tests/test_generic.py

@@ -440,6 +440,32 @@ def test_metadata_propagation_indiv(self):
         result = ts.resample('1T',how=lambda x: x.sum())
         self.check_metadata(ts,result)
 
+        _metadata = Series._metadata
+        _finalize = Series.__finalize__
+        Series._metadata = ['name','filename']
+        o.filename = 'foo'
+        o2.filename = 'bar'
+
+        def finalize(self, other, method=None, **kwargs):
+            for name in self._metadata:
+                if method == 'concat' and name == 'filename':
+                    value = '+'.join([ getattr(o,name) for o in other.objs if getattr(o,name,None) ])
+                    object.__setattr__(self, name, value)
+                else:
+                    object.__setattr__(self, name, getattr(other, name, None))
+
+            return self
+
+        Series.__finalize__ = finalize
+
+        result = pd.concat([o, o2])
+        self.assertEquals(result.filename,'foo+bar')
+        self.assertIsNone(result.name)
+
+        # reset
+        Series._metadata = _metadata
+        Series.__finalize__ = _finalize
+
     def test_interpolate(self):
         ts = Series(np.arange(len(self.ts), dtype=float), self.ts.index)
 
@@ -894,6 +920,28 @@ def finalize(self, other, method=None, **kwargs):
         result = df1.merge(df2, left_on=['a'], right_on=['c'], how='inner')
         self.assertEquals(result.filename,'fname1.csv|fname2.csv')
 
+        # concat
+        # GH 6927
+        DataFrame._metadata = ['filename']
+        df1 = DataFrame(np.random.randint(0, 4, (3, 2)), columns=list('ab'))
+        df1.filename = 'foo'
+
+        def finalize(self, other, method=None, **kwargs):
+            for name in self._metadata:
+                if method == 'concat':
+                    value = '+'.join([ getattr(o,name) for o in other.objs if getattr(o,name,None) ])
+                    object.__setattr__(self, name, value)
+                else:
+                    object.__setattr__(self, name, getattr(other, name, None))
+
+            return self
+
+        DataFrame.__finalize__ = finalize
+
+        result = pd.concat([df1, df1])
+        self.assertEquals(result.filename,'foo+foo')
+
+        # reset
         DataFrame._metadata = _metadata
         DataFrame.__finalize__ = _finalize
 

pandas/tools/merge.py

@@ -1064,18 +1064,18 @@ def get_result(self):
             new_data = com._concat_compat([x.get_values() for x in self.objs])
             name = com._consensus_name_attr(self.objs)
             new_data = self._post_merge(new_data)
-            return Series(new_data, index=self.new_axes[0], name=name)
+            return Series(new_data, index=self.new_axes[0], name=name).__finalize__(self, method='concat')
         elif self._is_series:
             data = dict(zip(range(len(self.objs)), self.objs))
             index, columns = self.new_axes
             tmpdf = DataFrame(data, index=index)
             if columns is not None:
                 tmpdf.columns = columns
-            return tmpdf
+            return tmpdf.__finalize__(self, method='concat')
         else:
             new_data = self._get_concatenated_data()
             new_data = self._post_merge(new_data)
-            return self.objs[0]._from_axes(new_data, self.new_axes)
+            return self.objs[0]._from_axes(new_data, self.new_axes).__finalize__(self, method='concat')
 
     def _post_merge(self, data):
         if isinstance(data, BlockManager):