`pydoc` inncorrectly assumes a module has documentation and where

[tripleee]

Bug report

Bug description:

>>> import encodings
>>> help(encodings)
Help on package encodings:

NAME
    encodings - Standard "encodings" Package

MODULE REFERENCE
    https://docs.python.org/3.14/library/encodings.html
    
    The following documentation is automatically generated from the Python
    source files.  It may be incomplete, incorrect or include features that
    are considered implementation detail and may vary between Python
    implementations.  When in doubt, consult the module reference at the
    location listed above.

DESCRIPTION
        Standard Python encoding modules are stored in this package
        directory.
    
        Codec modules must have names corresponding to normalized encoding
        names as defined in the normalize_encoding() function below, e.g.
        'utf-8' must be implemented by the module 'utf_8.py'.
    
        Each codec module must export the following interface:
[lines 1-23]
>>> print('\n'.join(x for x in pydoc.render_doc(encodings).splitlines() if 'http' in x))
    https://docs.python.org/3.14/library/encodings.html

The URL included here is not valid, and seems to be invalid at least back to Python 3.11.

I can't say if this has been deleted by mistake or if it was cleaned out and the documentation should no longer include it.

CPython versions tested on:

3.14

Operating systems tested on:

macOS

Linked PRs

• gh-84232: Fix pydoc docs.python.org link generation #139995

[terryjreedy]

Verified on Windows.

[StanFromIreland]

This is a pydoc issue, it does not support modules that are documented on the page of another module. In this case, encodings is documented on the codecs page: https://docs.python.org/3/library/codecs.html

[StanFromIreland]

From a duplicate report I see this is also done for private modules, from a quick look at the source, there is indeed no verification that the docs exist, it simply assumes they do and creates the link.

[StanFromIreland]

I will try to write a patch that extends our topics.py generation script to include a dictionary of canonical doc locations.

[zware]

See also gh-84232 and associated GH-29419.

[StanFromIreland]

Ah, that is a duplicate. Which one should we close?