sage -docbuild: error building docs of single file with relative imports #30475
Description
Follow-up from #29651:
The approach of SingleFileBuilder, creating a symlink to the source file, is not compatible with from .module import.
Example:
$ ./sage -docbuild file=src/sage/geometry/polyhedron/base.py html
[html ] building [html]: targets for 1 source files that are out of date
[html ] updating environment: [new config] 1 added, 0 changed, 0 removed
[html ] WARNING: autodoc: failed to import module 'base'; the following exception was raised:
[html ] attempted relative import with no known parent package
[html ] writing additional pages... searchdone
[html ] copying static files... ... done
[html ] dumping search index in English (code: en)... done
[html ] The HTML pages are in ../../../../.sage/docbuild/base/output/html.
Error building the documentation.
Instead, we should infer the fully qualified module name from the file name (see for example #30452) and import this module.
See also:
- expose building documentation for user modules not in the Sage library #6389 expose building documentation for user modules not in the Sage library
CC: @jhpalmieri @DaveWitteMorris
Component: build
Issue created by migration from https://trac.sagemath.org/ticket/30475