Docs build with Sphinx 8 #14595
Description
When building the ipython RPM package in Fedora Linux, we discovered that there is a configuration problem incompatible with the latest Sphinx 8:
ERROR: Invalid inventory location value `''` in intersphinx_mapping['python'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['rpy2'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['jupyterclient'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['jupyter'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['jedi'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['traitlets'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['ipykernel'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['prompt_toolkit'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['ipywidgets'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['ipyparallel'][1]. Inventory locations must be non-empty strings or None.
ERROR: Invalid inventory location value `''` in intersphinx_mapping['pip'][1]. Inventory locations must be non-empty strings or None.
Configuration error:
Invalid `intersphinx_mapping` configuration (11 errors).
It seems from the log that the fallback cannot be an empty string anymore.
The values are defined in:
ipython/docs/source/sphinx.toml
Lines 31 to 41 in 2a41aa5
And the problem is that there is no representation of None available in the TOML specification.