default memmap parameter to False

asdf/_asdf.py

@@ -57,7 +57,7 @@ def __init__(
         extensions=None,
         version=None,
         ignore_unrecognized_tag=False,
-        memmap=True,
+        memmap=False,
         lazy_load=True,
         custom_schema=None,
     ):
@@ -88,7 +88,7 @@ def __init__(
 
         memmap : bool, optional
             When `True`, when reading files, attempt to memmap underlying data
-            arrays when possible. Defaults to ``True``.
+            arrays when possible. Defaults to ``False``.
 
         lazy_load : bool, optional
             When `True` and the underlying file handle is seekable, data
@@ -1510,7 +1510,7 @@ def open_asdf(
     extensions=None,
     ignore_unrecognized_tag=False,
     _force_raw_types=False,
-    memmap=True,
+    memmap=False,
     lazy_tree=NotSet,
     lazy_load=True,
     custom_schema=None,
@@ -1549,7 +1549,7 @@ def open_asdf(
 
     memmap : bool, optional
         When `True`, when reading files, attempt to memmap underlying data
-        arrays when possible. Defaults to ``True``.
+        arrays when possible. Defaults to ``False``.
 
     lazy_load : bool, optional
         When `True` and the underlying file handle is seekable, data

asdf/_tests/tags/core/tests/test_ndarray.py

@@ -976,7 +976,7 @@ def test_memmap_write(tmp_path):
     tmpfile = str(tmp_path / "data.asdf")
     tree = {"data": np.zeros(100)}
 
-    with asdf.AsdfFile(tree) as af:
+    with asdf.AsdfFile(tree, memmap=False) as af:
         # Make sure we're actually writing to an internal array for this test
         af.write_to(tmpfile, all_array_storage="internal")
 
@@ -1002,7 +1002,7 @@ def test_readonly(tmp_path):
         af.write_to(tmpfile, all_array_storage="internal")
 
     # Opening in read mode (the default) should mean array is readonly
-    with asdf.open(tmpfile) as af:
+    with asdf.open(tmpfile, memmap=True) as af:
         assert af["data"].flags.writeable is False
         with pytest.raises(ValueError, match=r"assignment destination is read-only"):
             af["data"][0] = 41
@@ -1046,7 +1046,7 @@ def test_block_data_change(pad_blocks, tmp_path):
     with asdf.AsdfFile(tree) as af:
         af.write_to(tmpfile, pad_blocks=pad_blocks)
 
-    with asdf.open(tmpfile, mode="rw") as af:
+    with asdf.open(tmpfile, mode="rw", memmap=True) as af:
         assert np.all(af.tree["data"] == 0)
         array_before = af.tree["data"].__array__()
         af.tree["data"][:5] = 1

asdf/_tests/test_api.py

@@ -60,7 +60,7 @@ def test_open_readonly(tmp_path):
     os.chmod(tmpfile, 0o440)
     assert os.access(tmpfile, os.W_OK) is False
 
-    with asdf.open(tmpfile) as af:
+    with asdf.open(tmpfile, memmap=True) as af:
         assert af["baz"].flags.writeable is False
 
     with pytest.raises(PermissionError, match=r".* Permission denied: .*"), asdf.open(tmpfile, mode="rw"):

asdf/_tests/test_array_blocks.py

@@ -811,9 +811,11 @@ def filename_with_array(tmp_path_factory):
 @pytest.mark.parametrize(
     "open_kwargs,should_memmap",
     [
-        ({}, True),
-        ({"memmap": True}, True),
-        ({"memmap": False}, False),
+        ({}, False),
+        ({"lazy_load": True, "memmap": True}, True),
+        ({"lazy_load": False, "memmap": True}, True),
+        ({"lazy_load": True, "memmap": False}, False),
+        ({"lazy_load": False, "memmap": False}, False),
     ],
 )
 def test_open_no_memmap(filename_with_array, open_kwargs, should_memmap):
@@ -823,7 +825,7 @@ def test_open_no_memmap(filename_with_array, open_kwargs, should_memmap):
         default (no kwargs)
         memmap
     """
-    with asdf.open(filename_with_array, lazy_load=False, **open_kwargs) as af:
+    with asdf.open(filename_with_array, **open_kwargs) as af:
         array = af.tree["array"]
         if should_memmap:
             assert isinstance(array.base, np.memmap)

asdf/_tests/test_generic_io.py

@@ -110,7 +110,7 @@ def get_read_fd():
         f.read(0)
         return f
 
-    with _roundtrip(tree, get_write_fd, get_read_fd) as ff:
+    with _roundtrip(tree, get_write_fd, get_read_fd, read_options={"memmap": True}) as ff:
         assert len(ff._blocks.blocks) == 2
         assert isinstance(ff._blocks.blocks[0].cached_data, np.memmap)
 
@@ -133,7 +133,7 @@ def get_read_fd():
         assert f._uri == path.as_uri()
         return f
 
-    with _roundtrip(tree, get_write_fd, get_read_fd) as ff:
+    with _roundtrip(tree, get_write_fd, get_read_fd, read_options={"memmap": True}) as ff:
         assert len(ff._blocks.blocks) == 2
         assert isinstance(ff._blocks.blocks[0].cached_data, np.memmap)
 
@@ -173,7 +173,7 @@ def get_read_fd():
         assert f._uri == path.as_uri()
         return f
 
-    with _roundtrip(tree, get_write_fd, get_read_fd) as ff:
+    with _roundtrip(tree, get_write_fd, get_read_fd, read_options={"memmap": True}) as ff:
         assert len(ff._blocks.blocks) == 2
         assert isinstance(ff._blocks.blocks[0].cached_data, np.memmap)
         ff.tree["science_data"][0] = 42

asdf/_tests/test_reference.py

@@ -56,9 +56,6 @@ def do_asserts(ff):
 
         assert_array_equal(ff.tree["science_data"], exttree["cool_stuff"]["a"])
         assert len(ff._external_asdf_by_uri) == 1
-        with pytest.raises((ValueError, RuntimeError), match=r"assignment destination is read-only"):
-            # Assignment destination is readonly
-            ff.tree["science_data"][0] = 42
 
         assert_array_equal(ff.tree["science_data2"], exttree["cool_stuff"]["a"])
         assert len(ff._external_asdf_by_uri) == 2

changes/1801.general.rst

@@ -0,0 +1 @@
+Set ``memmap=False`` to default for ``asdf.open`` and ``AsdfFile.__init__``.

docs/asdf/whats_new.rst

@@ -46,6 +46,13 @@ Removed API
 New Defaults
 ------------
 
+.. _whats_new_4.0.0_memmap
+
+Memory mapping disabled by default
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Calls to ``asdf.open() and ``AsdfFile()`` will now default to ``memmap=False``, disabling memory mapping of arrays by default.
+
 .. _whats_new_4.0.0_validation:
 
 Validation