Hi people,

I Cc'd Damien because a few of these questions involve auth-source-pass,
and also Sam because they recently touched related areas in ERC. But
anyone in the know, please don't hold back. Your input is welcome.

In this bug set, I'm trying to make ERC smarter about how it integrates
with auth-source. The current implementation suffers directly from the
central problem this bug aims to address, namely, ERC's inability to
understand the concept of logical (IRC) connections and how they relate
to physical (TCP) connections.

Strategies stemming from this improved awareness require a prioritizing
of auth-source entries, not only when choosing query parameters but when
filtering returned results. In particular, various compatibility
crutches were required to make auth-source-pass produce output
conforming to the shape and substance delivered by the netrc back end.
The following patch set contains various unsightly machinations meant to
force a more agreeable outcome (agreeable to ERC, that is).

What I'm seeking from you (all) is confirmation that these patches don't
suffer from any glaring misconceptions regarding the API. Note that I'm
certainly *not* requesting any upstream changes, perhaps in part because
ERC is tethered to the past (currently 27.2), so we'd have to wait an
eternity before reaping any reward.

Anyway, when you have a sec, please glance briefly at the following
areas, all of them located in the first patch attached below:

 1. The new option `erc-auth-source-parameters-function'.

 2. The ERT tests residing in test/lisp/erc/erc-services-tests.el.
    Those should convey a feel for the behavior ERC is expecting.

 3. The various business-related functions that touch the API in
    lisp/erc/erc.el.

 4. The ugly adapters touching internal auth-source functions in
    lisp/erc/erc-compat.el.

The reaction I'm hoping for is something along the lines of "I see what
you're doing, and no, auth-source doesn't provide that OOTB, so knock
yourself out" or, conversely, "lo, you're going about that all wrong,
use this instead."

Thanks,
J.P.

P.S. For additional context, the full patch series can be found at
https://jpneverwas.gitlab.io/erc-tools/48598/patches.tar.gz
and additional integrations involving SASL can be found in #49860.