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PEP 810: Mark as accepted and address SC's feedback #4684

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pablogsal merged 1 commit into from
Nov 3, 2025
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PEP 810: Mark as accepted and address SC's feedback #4684

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20 changes: 19 additions & 1 deletion peps/pep-0810.rst
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Expand Up @@ -8,12 +8,13 @@ Author: Pablo Galindo <pablogsal@python.org>,
Noah Kim <noahbkim@gmail.com>,
Tim Stumbaugh <me@tjstum.com>
Discussions-To: https://discuss.python.org/t/104131
Status: Draft
Status: Accepted
Type: Standards Track
Created: 02-Oct-2025
Python-Version: 3.15
Post-History:
`03-Oct-2025 <https://discuss.python.org/t/104131>`__,
Resolution: `03-Nov-2025 <https://discuss.python.org/t/pep-810-explicit-lazy-imports/104131/466>`__


Abstract
Expand Down Expand Up @@ -361,6 +362,15 @@ being imported, and (if applicable) the fromlist. An import remains lazy only
if the filter function returns ``True``. If no lazy import filter is set, all
*potentially lazy* imports are lazy.

Note on .pth files
~~~~~~~~~~~~~~~~~~

The lazy import mechanism does not apply to .pth files processed by the
``site`` module. While .pth files have special handling for lines that begin
with ``import`` followed by a space or tab, this special handling will not be
adapted to support lazy imports. Imports specified in .pth files remain eager
as they always have been.

Lazy objects
------------

Expand Down Expand Up @@ -617,6 +627,9 @@ lazy imports filter:
``"normal"`` (respect ``lazy`` keyword only), ``"all"`` (force all imports to be
potentially lazy), or ``"none"`` (force all imports to be eager).

* ``sys.get_lazy_imports()`` - Returns the current lazy imports mode as a
string: ``"normal"``, ``"all"``, or ``"none"``.

The filter function is called for every potentially lazy import, and must
return ``True`` if the import should be lazy. This allows for fine-grained
control over which imports should be lazy, useful for excluding modules with
Expand Down Expand Up @@ -692,6 +705,11 @@ The global lazy imports flag can be controlled through:
* The ``PYTHON_LAZY_IMPORTS=<mode>`` environment variable
* The ``sys.set_lazy_imports(mode)`` function (primarily for testing)

The precedence order for setting the lazy imports mode follows the standard
Python pattern: ``sys.set_lazy_imports()`` takes highest precedence, followed
by ``-X lazy_imports=<mode>``, then ``PYTHON_LAZY_IMPORTS=<mode>``. If none
are specified, the mode defaults to ``"normal"``.

Where ``<mode>`` can be:

* ``"normal"`` (or unset): Only explicitly marked lazy imports are lazy
Expand Down