What’s New
4.0.0
Hi! Asdf 4.0.0 is a new major version including:
Removed API
The
copy_arrays
argument forasdf.open
andAsdfFile
has been removed and replaced bymemmap
(memmap == not copy_arrays
).ignore_version_mismatch
has had no effect since asdf 3.0.0 and was removed.the
asdf.util
submodule had several unused functions removed: -filepath_to_url
, seepathlib.Path.as_uri
as an alternative -is_primitive
, useisinstance
-iter_subclasses
, useobject.__subclasses__
-minversion
, seeastropy.utils.minversion
-resolve_name
, seeastropy.utils.resolve_name
-human_list
, usepprint
or your own string formattingversioning.AsdfSpec
, seeasdf.versioning.AsdfVersion
comparisonsasdf.testing.helpers.format_tag
, use your own string formattingAsdfFile.version_map
, could have been removed with the legacy extension APIAsdfFile.resolve_and_inline
, useAsdfFile.resolve_references
andall_array_storage=="inline"
asdf.asdf
, the public items in this submodule are all in the top levelasdf
moduleasdf.asdf.SerializationContext
, available atasdf.extension.SerializationContext
asdf.stream
, seeasdf.tags.core.Stream
ignore_implicit_conversion
has been removed (see Implicit Conversion below)providing a tag uri within a schema
$ref
will no longer resolve to the schema uri associated with that tag
New Defaults
Memory mapping disabled by default
Calls to asdf.open() and ``AsdfFile()
will now default to memmap=False
, disabling memory mapping of arrays by default.
ASDF standard version
By default asdf 4.0.0 will write files that use the 1.6.0 version of the
ASDF standard. This change should be transparent and all files
that use the older standards are readable. If you wish to write files
using the 1.5.0 (or older) ASDF standard you can provide a version
to AsdfFile.write_to
or change asdf.config.AsdfConfig.default_version
.
In addition to new schemas and tags ASDF standard 1.6.0 comes with a few other changes (scheduled for this version).
Opening files will no longer trigger
AsdfFile.fill_defaults
.Mapping keys are restricted to str, int, bool See YAML subset
Validation
Several operations no longer automatically trigger tree validation. These changes were made to limit the number of times a tree is validated to allow incremental construction of trees and to improve performance.
providing a tree to
AsdfFile.__init__
no longer triggers validationcalling
AsdfFile.resolve_references
no longer triggers validationassigning a new tree to
AsdfFile.tree
no longer triggers validation
Note
Validation can be triggered with AsdfFile.validate
and will
occur when writing to a file (or reading if AsdfConfig.validate_on_read
is enabled).
Find References
Similar to Validation several operations no longer
automatically trigger AsdfFile.find_references
:
asdf.open
does not triggerAsdfFile.find_references
providing a tree (or
AsdfFile
) toAsdfFile.__init__
no longer triggersAsdfFile.find_references
Note
AsdfFile.find_references
is only for JSON pointer references
which are most useful for external references. YAML anchors and
aliases are automatically resolved.
Implicit Conversion
In older asdf versions namedtuple
instances were automatically
converted to lists when written to a file. When read back in the
namedtuple
was not reconstructed and instead these objects were
returned as lists. With asdf 4.0.0 this “implicit conversion” is
no longer performed which allows extensions to implement converters
for namedtuple
instances.
Unknown NDArray Subclasses
In asdf 3.0.0 a config attribute was added
asdf.config.AsdfConfig.convert_unknown_ndarray_subclasses
that
was enabled by default (to retain the behavior of the removed legacy
extension that handled ndarrays).
In asdf 4.0.0 this setting is disabled by default and issues a deprecation warning when enabled. In an upcoming version of asdf this setting will be removed.
See convert_unknown_ndarray_subclasses for more details.
3.0.0
Asdf 3.0.0 is the first major asdf release since 2018.
Thank you to all the contributors!
Removed features
The following deprecated features are removed in asdf 3.0.0:
Please see the links above or the Deprecations for more details.
New features
As asdf now only supports new-style extensions several new features were added to allow these extensions to retain all the functionality of the now removed type system.
Converters can now defer conversion allowing a different converter to handle serailizing an object. This is useful if a subclass instance can be safely converted to a superclass during serialization. See Deferring to another converter for an example and more information.
Converters can now access ASDF block storage. during serialization and deserialization. See Block storage for examples and more information.
Converters have always been “strict” about tag version mismatches (returning ‘raw’ objects if a specific tag version is not supported). This “strictness” now extends to all objects handled by asdf. As all known asdf extensions have already migrated to converters this should pose no issue for users. Please open an issue if you run into any difficulty.
Internal changes
2.15.1 included internally a version of jsonschema. See the jsonschema sub-section of the 2.15.1 section for more details. Asdf 3.0.0 drops jsonschema as a dependency. If your software requires jsonschema be sure to add it to your dependencies.
To accomplish the above improvements to asdf extensions, a major rewrite of
the ASDF block management code was required. During this rewrite
AsdfBlockIndexWarning
was added which users will see if they open an ASDF
file with an invalid block index. Re-saving the file (or removing the
optional block index) is often sufficient to fix the file so it no longer
issues the warning when opened.
Upcoming changes
With the release of asdf 3.0.0 the developers are beginning work on 3.1.0 and 4.0.0. One major change being considered for asdf 4.0.0 is the disabling of memory mapping as the default option when as ASDF file is opened. Memory mapping can offer significant performance gains but also increases the chance for gnarly errors like segfaults and corrupt data. Please let us know if this change would impact your use of asdf in the newly opened asdf discussions
In an attempt to construct a coherent api, asdf 3.1 (and additional minor versions) will likely contain new deprecations in an effort to reorganize and clean up the api. If you are using features that are not currently listed in the User API or Developer API documentation please open an issue. This will help us to know what functions should be preserved, what requires a deprecation prior to removal and which of our un-documented (non-public) features can be removed without a deprecation.
2.15.1
jsonschema
Asdf 2.15.1 includes internally a version of jsonschema 4.17.3. This inclusion was done to deal with incompatible changes in jsonschema 4.18.
Many libraries that use asdf import jsonschema to allow catching of ValidationError
instances that might be raised during schema validation. Prior to asdf 2.15 this
error type was not part of the public asdf API. For 2.15 and later users are
expected to import ValidationError
from asdf.exceptions
(instead of jsonschema
directly).
To further ease the transition, asdf will, when possible, use exceptions imported
from any installed version of jsonschema. This means that when the asdf internal
jsonschema raises a ValidationError
on a system where jsonschema was separately
installed, the internal jsonschema will attempt to use ValidationError
from the
installed version. This should allow code that catches exceptions imported from
jsonschema to continue to work with no changes. However, asdf cannot guarantee
compatibility with future installed jsonschema versions and users are encouraged
to update their code to import ValidationError
from asdf.exceptions
.
Finally, asdf is temporarily keeping jsonschema as a dependency as many libraries expected this to be installed by asdf. We expect to drop this requirement soon (likely in 3.0.0) and this change might occur in a minor or even patch version.