BUG: Remove auto_close option form read_hdf, #9327, #10330

Remove docstring indicating auto_close can be used in read_hdf.
This value is always ignored.
Also correctly implements support for passing open HDFStores.
Adds error handling for unknown buffer-types.

xref #9327

Author: Kevin Sheppard

doc/source/whatsnew/v0.16.2.txt

@@ -171,3 +171,6 @@ Bug Fixes
 - Bug in ``read_csv`` with a ``date_parser`` that returned a ``datetime64`` array of other time resolution than ``[ns]`` (:issue:`10245`)
 
 - Bug in ``Panel.apply`` when the result has ndim = 0 (:issue:`10332`)
+
+- Bug in ``read_hdf`` where ``auto_close`` could not be passed (:issue:`9327`).
+- Bug in ``read_hdf`` where open stores could not be used (:issue:`10330`).

pandas/io/pytables.py

@@ -290,8 +290,6 @@ def read_hdf(path_or_buf, key, **kwargs):
             return columns
         iterator : optional, boolean, return an iterator, default False
         chunksize : optional, nrows to include in iteration, return an iterator
-        auto_close : optional, boolean, should automatically close the store
-            when finished, default is False
 
         Returns
         -------
@@ -303,9 +301,6 @@ def read_hdf(path_or_buf, key, **kwargs):
     if 'where' in kwargs:
         kwargs['where'] = _ensure_term(kwargs['where'], scope_level=1)
 
-    f = lambda store, auto_close: store.select(
-        key, auto_close=auto_close, **kwargs)
-
     if isinstance(path_or_buf, string_types):
 
         try:
@@ -321,20 +316,28 @@ def read_hdf(path_or_buf, key, **kwargs):
         # can't auto open/close if we are using an iterator
         # so delegate to the iterator
         store = HDFStore(path_or_buf, **kwargs)
-        try:
-            return f(store, True)
-        except:
+        auto_close = True
 
-            # if there is an error, close the store
-            try:
-                store.close()
-            except:
-                pass
+    elif isinstance(path_or_buf, HDFStore):
+        if not path_or_buf.is_open:
+            raise IOError('The HDFStore must be open for reading.')
 
-            raise
+        store = path_or_buf
+        auto_close = False
+    else:
+        raise NotImplementedError('Support for generic buffers has not been '
+                                  'implemented.')
+
+    try:
+        return store.select(key, auto_close=auto_close, **kwargs)
+    except:
+        # if there is an error, close the store
+        try:
+            store.close()
+        except:
+            pass
 
-    # a passed store; user controls open/close
-    f(path_or_buf, False)
+        raise
 
 
 class HDFStore(StringMixin):

pandas/io/tests/test_pytables.py

@@ -13,7 +13,7 @@
 from pandas import (Series, DataFrame, Panel, MultiIndex, Categorical, bdate_range,
                     date_range, timedelta_range, Index, DatetimeIndex, TimedeltaIndex, isnull)
 
-from pandas.io.pytables import _tables
+from pandas.io.pytables import _tables, TableIterator
 try:
     _tables()
 except ImportError as e:
@@ -4670,6 +4670,54 @@ def test_to_hdf_with_object_column_names(self):
                 assert(len(result))
 
 
+    def test_read_hdf_open_store(self):
+        # GH10330
+        # No check for non-string path_or-buf, and no test of open store
+        df = DataFrame(np.random.rand(4, 5),
+                       index=list('abcd'),
+                       columns=list('ABCDE'))
+        df.index.name = 'letters'
+        df = df.set_index(keys='E', append=True)
+
+        with ensure_clean_path(self.path) as path:
+            df.to_hdf(path, 'df', mode='w')
+            direct = read_hdf(path, 'df')
+            store = HDFStore(path, mode='r')
+            indirect = read_hdf(store, 'df')
+            tm.assert_frame_equal(direct, indirect)
+            self.assertTrue(store.is_open)
+            store.close()
+
+    def test_read_hdf_iterator(self):
+        df = DataFrame(np.random.rand(4, 5),
+                       index=list('abcd'),
+                       columns=list('ABCDE'))
+        df.index.name = 'letters'
+        df = df.set_index(keys='E', append=True)
+
+        with ensure_clean_path(self.path) as path:
+            df.to_hdf(path, 'df', mode='w', format='t')
+            direct = read_hdf(path, 'df')
+            iterator = read_hdf(path, 'df', iterator=True)
+            self.assertTrue(isinstance(iterator, TableIterator))
+            indirect = next(iterator.__iter__())
+            tm.assert_frame_equal(direct, indirect)
+            iterator.store.close()
+
+    def test_read_hdf_errors(self):
+        df = DataFrame(np.random.rand(4, 5),
+                       index=list('abcd'),
+                       columns=list('ABCDE'))
+
+        with ensure_clean_path(self.path) as path:
+            self.assertRaises(IOError, read_hdf, path, 'key')
+            df.to_hdf(path, 'df')
+            store = HDFStore(path, mode='r')
+            store.close()
+            self.assertRaises(IOError, read_hdf, store, 'df')
+            with open(path, mode='r') as store:
+                self.assertRaises(NotImplementedError, read_hdf, store, 'df')
+
 def _test_sort(obj):
     if isinstance(obj, DataFrame):
         return obj.reindex(sorted(obj.index))