Clarify the role of the egg URL fragment

[sbidoul]

Clarify that the egg fragment is only necessary for editable VCS installs, and otherwise not necessary anymore.

[pradyunsg]

Should we try to allow -e pep508@git+... and completely eliminate #egg URLs?

[sbidoul]

Should we try to allow -e pep508@git+... and completely eliminate #egg URLs?

We should, yes. @uranusjr investigated that in #9471.

[sbidoul]

Rebased

[uranusjr]

Using PEP 508 syntax for editable is still blocked by pypa/packaging#264 for the moment.

[sbidoul]

Using PEP 508 syntax for editable is still blocked by pypa/packaging#264 for the moment.

Partly, but I think that one only blocks git+file:// URLs ?

IIRC, the slightly complicated part is allowing name[extras] @ absolute_or_relative_local_path which is not PEP 508 syntax because absolute_or_relative_local_path is not an URI.

updated: hm, no we can do pip install -e "absolute_or_relative_local_path[extras]" today without involving the project name, so pip install -e "name @ uri" might be all we need.