URL Functions

[MGatner]

Description
The next stage of reworking URI handling, this PR refactors the URL Helper's *_url() functions to use a new internal helper, _get_uri(). This should a) make clearer what each function does, and b) fix a few bugs, including the "big one" #4116.

Due to #4116 I expect there to be failures from dependent components. This will give some idea of the impact this could have on developers who have been expecting current_url() to leave off indexPage, even though that creates invalid project URLs. In anticipation of this upset we will need some loud screaming in the changelog and release notes.

Note: This relies on #4672 and will need to be rebased after that is merged.

Checklist:

• Securely signed commits
• Component(s) with PHPdocs
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[lonnieezell]

I agree we need to shout about this one, but it fixes what needs to be fixed. Thanks.

I don't see any issues with it.

[MGatner]

@lonnieezell See if you think these User Guide changes are appropriate and sufficient.

[lonnieezell]

Yes, I think those changes are sufficient. Will want to include info about that in our release notice, too.

[paulbalandan]

We should also document the changes in the function signatures.

[MGatner]

@paulbalandan I already updated the function comments to match what it now does a bit more accurately. Did you mean something like, "Note: this function has changed to..."?

[paulbalandan]

I meant the documentation in url_helper.rst

[MGatner]

@paulbalandan Something like this?

[paulbalandan]

@paulbalandan Something like this?

Ah I see it now. The insertion of the _get_uri function complicated the diff views. I thought the signatures changed.

Oh, the current_url function has now a nullable second param. We should update that in the docs.

[MGatner]

Good catch! Added.