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gh-93610: Improve docs for importlib.resources #93611

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Jul 25, 2022
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gh-93610: Improve docs for importlib.resources #93611

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6a97526
Add a concrete example of why you'd use importlib.resources over Path…
encukou Jun 8, 2022
77b50ae
Link to the definition of a new term
encukou Jun 8, 2022
89f00a2
Add importlib.resources.abc docs to the hierarchy, to fix links
encukou Jun 8, 2022
9134901
Package: Document what this is first, then give the formal definition
encukou Jun 8, 2022
0274515
Shorten links to Traversable
encukou Jun 8, 2022
39ab32a
Link to Package
encukou Jun 8, 2022
521ad26
Move deprecated functions to a dedicated section, add modern equivalents
encukou Jun 8, 2022
719562b
Move replacements to the ..deprecated sections
encukou Jun 8, 2022
9bcca6b
Remove the link to migrating legacy usage: this is now documented here.
encukou Jun 8, 2022
ac007c3
Remove `errors` arguments from the migration snippets
encukou Jun 8, 2022
d1fefcb
Fix qualname of importlib.resources.abc.ResourceReader
encukou Jun 8, 2022
993ea9e
Reword the intro for deprecated functions
encukou Jun 8, 2022
77acd33
Remove unnecessary "headings"
encukou Jun 8, 2022
1fb51a0
Apply suggestions from code review
encukou Jun 9, 2022
a5a5377
Move classes that are actually in importlib.abc out from importlib.re…
encukou Jun 16, 2022
a03df1f
Fix references to classes in importlib.resources.abc
encukou Jun 16, 2022
85ad3c7
Merge remote-tracking branch 'upstream/main' into impres-docs
ambv Jul 25, 2022
fa68025
Slightly reword Package
ambv Jul 25, 2022
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263 changes: 15 additions & 248 deletions Doc/library/importlib.resources.abc.rst
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Original file line number Diff line number Diff line change
@@ -1,3 +1,15 @@
:mod:`importlib.resources.abc` -- Abstract base classes for resources
---------------------------------------------------------------------

.. module:: importlib.resources.abc
:synopsis: Abstract base classes for resources

**Source code:** :source:`Lib/importlib/resources/abc.py`

--------------

.. versionadded:: 3.11

.. class:: ResourceReader

*Superseded by TraversableResources*
Expand Down Expand Up @@ -72,251 +84,6 @@
The abstract method returns an iterable of no items.


.. class:: ResourceLoader

An abstract base class for a :term:`loader` which implements the optional
:pep:`302` protocol for loading arbitrary resources from the storage
back-end.

.. deprecated:: 3.7
This ABC is deprecated in favour of supporting resource loading
through :class:`importlib.abc.ResourceReader`.

.. abstractmethod:: get_data(path)

An abstract method to return the bytes for the data located at *path*.
Loaders that have a file-like storage back-end
that allows storing arbitrary data
can implement this abstract method to give direct access
to the data stored. :exc:`OSError` is to be raised if the *path* cannot
be found. The *path* is expected to be constructed using a module's
:attr:`__file__` attribute or an item from a package's :attr:`__path__`.

.. versionchanged:: 3.4
Raises :exc:`OSError` instead of :exc:`NotImplementedError`.


.. class:: InspectLoader

An abstract base class for a :term:`loader` which implements the optional
:pep:`302` protocol for loaders that inspect modules.

.. method:: get_code(fullname)

Return the code object for a module, or ``None`` if the module does not
have a code object (as would be the case, for example, for a built-in
module). Raise an :exc:`ImportError` if loader cannot find the
requested module.

.. note::
While the method has a default implementation, it is suggested that
it be overridden if possible for performance.

.. index::
single: universal newlines; importlib.abc.InspectLoader.get_source method

.. versionchanged:: 3.4
No longer abstract and a concrete implementation is provided.

.. abstractmethod:: get_source(fullname)

An abstract method to return the source of a module. It is returned as
a text string using :term:`universal newlines`, translating all
recognized line separators into ``'\n'`` characters. Returns ``None``
if no source is available (e.g. a built-in module). Raises
:exc:`ImportError` if the loader cannot find the module specified.

.. versionchanged:: 3.4
Raises :exc:`ImportError` instead of :exc:`NotImplementedError`.

.. method:: is_package(fullname)

An optional method to return a true value if the module is a package, a
false value otherwise. :exc:`ImportError` is raised if the
:term:`loader` cannot find the module.

.. versionchanged:: 3.4
Raises :exc:`ImportError` instead of :exc:`NotImplementedError`.

.. staticmethod:: source_to_code(data, path='<string>')

Create a code object from Python source.

The *data* argument can be whatever the :func:`compile` function
supports (i.e. string or bytes). The *path* argument should be
the "path" to where the source code originated from, which can be an
abstract concept (e.g. location in a zip file).

With the subsequent code object one can execute it in a module by
running ``exec(code, module.__dict__)``.

.. versionadded:: 3.4

.. versionchanged:: 3.5
Made the method static.

.. method:: exec_module(module)

Implementation of :meth:`Loader.exec_module`.

.. versionadded:: 3.4

.. method:: load_module(fullname)

Implementation of :meth:`Loader.load_module`.

.. deprecated:: 3.4
use :meth:`exec_module` instead.


.. class:: ExecutionLoader

An abstract base class which inherits from :class:`InspectLoader` that,
when implemented, helps a module to be executed as a script. The ABC
represents an optional :pep:`302` protocol.

.. abstractmethod:: get_filename(fullname)

An abstract method that is to return the value of :attr:`__file__` for
the specified module. If no path is available, :exc:`ImportError` is
raised.

If source code is available, then the method should return the path to
the source file, regardless of whether a bytecode was used to load the
module.

.. versionchanged:: 3.4
Raises :exc:`ImportError` instead of :exc:`NotImplementedError`.


.. class:: FileLoader(fullname, path)

An abstract base class which inherits from :class:`ResourceLoader` and
:class:`ExecutionLoader`, providing concrete implementations of
:meth:`ResourceLoader.get_data` and :meth:`ExecutionLoader.get_filename`.

The *fullname* argument is a fully resolved name of the module the loader is
to handle. The *path* argument is the path to the file for the module.

.. versionadded:: 3.3

.. attribute:: name

The name of the module the loader can handle.

.. attribute:: path

Path to the file of the module.

.. method:: load_module(fullname)

Calls super's ``load_module()``.

.. deprecated:: 3.4
Use :meth:`Loader.exec_module` instead.

.. abstractmethod:: get_filename(fullname)

Returns :attr:`path`.

.. abstractmethod:: get_data(path)

Reads *path* as a binary file and returns the bytes from it.


.. class:: SourceLoader

An abstract base class for implementing source (and optionally bytecode)
file loading. The class inherits from both :class:`ResourceLoader` and
:class:`ExecutionLoader`, requiring the implementation of:

* :meth:`ResourceLoader.get_data`
* :meth:`ExecutionLoader.get_filename`
Should only return the path to the source file; sourceless
loading is not supported.

The abstract methods defined by this class are to add optional bytecode
file support. Not implementing these optional methods (or causing them to
raise :exc:`NotImplementedError`) causes the loader to
only work with source code. Implementing the methods allows the loader to
work with source *and* bytecode files; it does not allow for *sourceless*
loading where only bytecode is provided. Bytecode files are an
optimization to speed up loading by removing the parsing step of Python's
compiler, and so no bytecode-specific API is exposed.

.. method:: path_stats(path)

Optional abstract method which returns a :class:`dict` containing
metadata about the specified path. Supported dictionary keys are:

- ``'mtime'`` (mandatory): an integer or floating-point number
representing the modification time of the source code;
- ``'size'`` (optional): the size in bytes of the source code.

Any other keys in the dictionary are ignored, to allow for future
extensions. If the path cannot be handled, :exc:`OSError` is raised.

.. versionadded:: 3.3

.. versionchanged:: 3.4
Raise :exc:`OSError` instead of :exc:`NotImplementedError`.

.. method:: path_mtime(path)

Optional abstract method which returns the modification time for the
specified path.

.. deprecated:: 3.3
This method is deprecated in favour of :meth:`path_stats`. You don't
have to implement it, but it is still available for compatibility
purposes. Raise :exc:`OSError` if the path cannot be handled.

.. versionchanged:: 3.4
Raise :exc:`OSError` instead of :exc:`NotImplementedError`.

.. method:: set_data(path, data)

Optional abstract method which writes the specified bytes to a file
path. Any intermediate directories which do not exist are to be created
automatically.

When writing to the path fails because the path is read-only
(:attr:`errno.EACCES`/:exc:`PermissionError`), do not propagate the
exception.

.. versionchanged:: 3.4
No longer raises :exc:`NotImplementedError` when called.

.. method:: get_code(fullname)

Concrete implementation of :meth:`InspectLoader.get_code`.

.. method:: exec_module(module)

Concrete implementation of :meth:`Loader.exec_module`.

.. versionadded:: 3.4

.. method:: load_module(fullname)

Concrete implementation of :meth:`Loader.load_module`.

.. deprecated:: 3.4
Use :meth:`exec_module` instead.

.. method:: get_source(fullname)

Concrete implementation of :meth:`InspectLoader.get_source`.

.. method:: is_package(fullname)

Concrete implementation of :meth:`InspectLoader.is_package`. A module
is determined to be a package if its file path (as provided by
:meth:`ExecutionLoader.get_filename`) is a file named
``__init__`` when the file extension is removed **and** the module name
itself does not end in ``__init__``.


.. class:: Traversable

An object with a subset of pathlib.Path methods suitable for
Expand Down Expand Up @@ -369,8 +136,8 @@

An abstract base class for resource readers capable of serving
the :meth:`importlib.resources.files` interface. Subclasses
:class:`importlib.abc.ResourceReader` and provides
concrete implementations of the :class:`importlib.abc.ResourceReader`'s
:class:`importlib.resources.abc.ResourceReader` and provides
concrete implementations of the :class:`importlib.resources.abc.ResourceReader`'s
abstract methods. Therefore, any loader supplying
:class:`importlib.abc.TraversableReader` also supplies ResourceReader.

Expand All @@ -381,5 +148,5 @@

.. abstractmethod:: files()

Returns a :class:`importlib.abc.Traversable` object for the loaded
Returns a :class:`importlib.resources.abc.Traversable` object for the loaded
package.