Factor out deprecation logic

python/pyarrow/feather.py

@@ -26,6 +26,8 @@ from pyarrow.compat import pdapi
 from pyarrow.lib import FeatherError  # noqa
 from pyarrow.lib import RecordBatch, Table, concat_tables
 import pyarrow.lib as ext
+from .util import _deprecate_nthreads
+
 
 try:
     infer_dtype = pdapi.infer_dtype
@@ -67,10 +69,7 @@ class FeatherReader(ext.FeatherReader):
         return table
 
     def read_pandas(self, columns=None, nthreads=None, use_threads=False):
-        if nthreads is not None:
-            warnings.warn("`nthreads` argument is ignored, "
-                          "pass `use_threads` instead", FutureWarning,
-                          stacklevel=2)
+        use_threads = _deprecate_nthreads(use_threads, nthreads)
         return self.read_table(columns=columns).to_pandas(
             use_threads=use_threads)
 
@@ -162,10 +161,7 @@ class FeatherDataset(object):
         pandas.DataFrame
             Content of the file as a pandas DataFrame (of columns)
         """
-        if nthreads is not None:
-            warnings.warn("`nthreads` argument is ignored, "
-                          "pass `use_threads` instead", FutureWarning,
-                          stacklevel=2)
+        use_threads = _deprecate_nthreads(use_threads, nthreads)
         return self.read_table(columns=columns).to_pandas(
             use_threads=use_threads)
 
@@ -213,10 +209,7 @@ def read_feather(source, columns=None, nthreads=None, use_threads=False):
     -------
     df : pandas.DataFrame
     """
-    if nthreads is not None:
-        warnings.warn("`nthreads` argument is ignored, "
-                      "pass `use_threads` instead", FutureWarning,
-                      stacklevel=2)
+    use_threads = _deprecate_nthreads(use_threads, nthreads)
     reader = FeatherReader(source)
     return reader.read_pandas(columns=columns, use_threads=use_threads)
 

python/pyarrow/ipc.py

@@ -17,8 +17,6 @@
 
 # Arrow file and stream reader/writer classes, and other messaging tools
 
-import warnings
-
 import pyarrow as pa
 
 from pyarrow.lib import (Message, MessageReader,  # noqa
@@ -26,6 +24,7 @@ from pyarrow.lib import (Message, MessageReader,  # noqa
                          read_tensor, write_tensor,
                          get_record_batch_size, get_tensor_size)
 import pyarrow.lib as lib
+from .util import _deprecate_nthreads
 
 
 class _ReadPandasOption(object):
@@ -184,10 +183,7 @@ def deserialize_pandas(buf, nthreads=None, use_threads=False):
     -------
     df : pandas.DataFrame
     """
-    if nthreads is not None:
-        warnings.warn("`nthreads` argument is ignored, "
-                      "pass `use_threads` instead", FutureWarning,
-                      stacklevel=2)
+    use_threads = _deprecate_nthreads(use_threads, nthreads)
 
     buffer_reader = pa.BufferReader(buf)
     reader = pa.RecordBatchStreamReader(buffer_reader)

python/pyarrow/table.pxi

@@ -16,7 +16,6 @@
 # under the License.
 
 import json
-import warnings
 
 from collections import OrderedDict
 
@@ -28,6 +27,8 @@ except ImportError:
 else:
     import pyarrow.pandas_compat as pdcompat
 
+from .util import _deprecate_nthreads
+
 
 cdef class ChunkedArray:
     """
@@ -755,10 +756,7 @@ cdef class RecordBatch:
         -------
         pandas.DataFrame
         """
-        if nthreads is not None:
-            warnings.warn("`nthreads` argument is ignored, "
-                          "pass `use_threads` instead", FutureWarning,
-                          stacklevel=2)
+        use_threads = _deprecate_nthreads(use_threads, nthreads)
         return Table.from_batches([self]).to_pandas(use_threads=use_threads)
 
     @classmethod
@@ -1180,10 +1178,7 @@ cdef class Table:
         cdef:
             PandasOptions options
 
-        if nthreads is not None:
-            warnings.warn("`nthreads` argument is ignored, "
-                          "pass `use_threads` instead", FutureWarning,
-                          stacklevel=2)
+        use_threads = _deprecate_nthreads(use_threads, nthreads)
 
         options = PandasOptions(
             strings_to_categorical=strings_to_categorical,

python/pyarrow/util.py

@@ -35,3 +35,13 @@ def _deprecate_api(old_name, new_name, api, next_version):
         warnings.warn(msg, FutureWarning)
         return api(*args)
     return wrapper
+
+
+def _deprecate_nthreads(use_threads, nthreads):
+    if nthreads is not None:
+        warnings.warn("`nthreads` argument is deprecated, "
+                      "pass `use_threads` instead", FutureWarning,
+                      stacklevel=3)
+        if nthreads > 1:
+            use_threads = True
+    return use_threads