Merge pull request #15421 from sethtroisi/contextlib_py2

ENH: Make use of ExitStack in npyio.py

1 files changed, 12 insertions, 21 deletions

diff --git a/numpy/lib/npyio.py b/numpy/lib/npyio.py
index f43fcf0c0..50f309938 100644
--- a/numpy/lib/npyio.py
+++ b/numpy/lib/npyio.py
@@ -408,15 +408,14 @@ def load(file, mmap_mode=None, allow_pickle=False, fix_imports=True,
 
     pickle_kwargs = dict(encoding=encoding, fix_imports=fix_imports)
 
-    # TODO: Use contextlib.ExitStack once we drop Python 2
-    if hasattr(file, 'read'):
-        fid = file
-        own_fid = False
-    else:
-        fid = open(os_fspath(file), "rb")
-        own_fid = True
+    with contextlib.ExitStack() as stack:
+        if hasattr(file, 'read'):
+            fid = file
+            own_fid = False
+        else:
+            fid = stack.enter_context(open(os_fspath(file), "rb"))
+            own_fid = True
 
-    try:
         # Code to distinguish from NumPy binary files and pickles.
         _ZIP_PREFIX = b'PK\x03\x04'
         _ZIP_SUFFIX = b'PK\x05\x06' # empty zip files start with this
@@ -427,10 +426,10 @@ def load(file, mmap_mode=None, allow_pickle=False, fix_imports=True,
         fid.seek(-min(N, len(magic)), 1)  # back-up
         if magic.startswith(_ZIP_PREFIX) or magic.startswith(_ZIP_SUFFIX):
             # zip-file (assume .npz)
-            # Transfer file ownership to NpzFile
+            # Potentially transfer file ownership to NpzFile
+            stack.pop_all()
             ret = NpzFile(fid, own_fid=own_fid, allow_pickle=allow_pickle,
                           pickle_kwargs=pickle_kwargs)
-            own_fid = False
             return ret
         elif magic == format.MAGIC_PREFIX:
             # .npy file
@@ -449,9 +448,6 @@ def load(file, mmap_mode=None, allow_pickle=False, fix_imports=True,
             except Exception:
                 raise IOError(
                     "Failed to interpret file %s as a pickle" % repr(file))
-    finally:
-        if own_fid:
-            fid.close()
 
 
 def _save_dispatcher(file, arr, allow_pickle=None, fix_imports=None):
@@ -519,23 +515,18 @@ def save(file, arr, allow_pickle=True, fix_imports=True):
     >>> print(a, b)
     # [1 2] [1 3]
     """
-    own_fid = False
     if hasattr(file, 'write'):
-        fid = file
+        file_ctx = contextlib_nullcontext(file)
     else:
         file = os_fspath(file)
         if not file.endswith('.npy'):
             file = file + '.npy'
-        fid = open(file, "wb")
-        own_fid = True
+        file_ctx = open(file, "wb")
 
-    try:
+    with file_ctx as fid:
         arr = np.asanyarray(arr)
         format.write_array(fid, arr, allow_pickle=allow_pickle,
                            pickle_kwargs=dict(fix_imports=fix_imports))
-    finally:
-        if own_fid:
-            fid.close()
 
 
 def _savez_dispatcher(file, *args, **kwds):