give nicer deprecation / message on infer_dtype moving

Author: jreback

pandas/__init__.py

@@ -62,7 +62,8 @@
 
 json = _DeprecatedModule(deprmod='pandas.json', deprmodto='pandas.io.json.libjson')
 parser = _DeprecatedModule(deprmod='pandas.parser', deprmodto='pandas.io.libparsers')
-lib = _DeprecatedModule(deprmod='pandas.lib', deprmodto='pandas._libs.lib')
+lib = _DeprecatedModule(deprmod='pandas.lib', deprmodto='pandas._libs.lib',
+                        moved={'infer_dtype': 'pandas.api.lib.infer_dtype'})
 tslib = _DeprecatedModule(deprmod='pandas.tslib', deprmodto='pandas._libs.tslib')
 
 # use the closest tagged version if possible

pandas/tests/api/test_api.py

@@ -187,7 +187,7 @@ class TestLib(tm.TestCase):
 
     def test_deprecation_access_func(self):
         with catch_warnings(record=True):
-            pd.lib.infer_dtype
+            pd.lib.infer_dtype('foo')
 
 
 class TestTSLib(tm.TestCase):

pandas/tests/api/test_lib.py

@@ -1,11 +1,10 @@
 # -*- coding: utf-8 -*-
 
-import pytest
+from warnings import catch_warnings
 import pandas  # noqa
 
 
-@pytest.mark.parametrize('f', ['infer_dtype'])
-def test_importable(f):
-    from pandas.api import lib
-    e = getattr(lib, f)
-    assert e is not None
+def test_moved_infer_dtype():
+    with catch_warnings(record=True):
+        e = pandas.lib.infer_dtype('foo')
+        assert e is not None

pandas/util/depr_module.py

@@ -18,14 +18,19 @@ class _DeprecatedModule(object):
                 be used when needed.
     removals : objects or methods in module that will no longer be
                accessible once module is removed.
+    moved : dict, optional
+            dictionary of function name -> new location for moved
+            objects
     """
 
-    def __init__(self, deprmod, deprmodto=None, removals=None):
+    def __init__(self, deprmod, deprmodto=None, removals=None,
+                 moved=None):
         self.deprmod = deprmod
         self.deprmodto = deprmodto
         self.removals = removals
         if self.removals is not None:
             self.removals = frozenset(self.removals)
+        self.moved = moved
 
         # For introspection purposes.
         self.self_dir = frozenset(dir(self.__class__))
@@ -60,6 +65,14 @@ def __getattr__(self, name):
                 "{deprmod}.{name} is deprecated and will be removed in "
                 "a future version.".format(deprmod=self.deprmod, name=name),
                 FutureWarning, stacklevel=2)
+        elif self.moved is not None and name in self.moved:
+            warnings.warn(
+                "{deprmod} is deprecated and will be removed in "
+                "a future version.\nYou can access {name} in {moved}".format(
+                    deprmod=self.deprmod,
+                    name=name,
+                    moved=self.moved[name]),
+                FutureWarning, stacklevel=2)
         else:
             deprmodto = self.deprmodto
             if deprmodto is None: