* doc/misc/url.texi: Mention version 4a in SOCKS portion of "Gateways
in general" node.
* etc/NEWS: Mention version 4a support in new `socks' section.
* lisp/net/socks.el (socks-server): Add new Custom choice `4a' for
version field. This change does not further overload the field in
terms of expected type because `socks-send-command' and `socks-filter'
already accommodate the symbol `http'.
(socks--errors-4): Add new constant containing error messages for
version 4. The semantics are faithful to the de facto spec, but the
exact wording is slightly adapted.
(socks-filter): Allow for a null "type" field on error with version 5.
Previously, certain errors would not propagate because a wrong-type
signal would get in the way.
(socks-send-command): Massage existing version 4 protocol parsing to
accommodate 4a, and add error handling for version 4. Use variable
`socks-username' for v4 variable-length ID field instead of calling
`user-full-name', which has potential privacy implications.
* test/lisp/net/socks-tests.el (socks-tests-v4-basic): Don't mock
`user-full-name' because `socks-send-command' no longer calls it to
determine the ID.
(socks-tests-v4a-basic, socks-tests-v4a-error): Add a couple tests for
SOCKS version 4a. (Bug#53941)
* test/lisp/net/socks-tests.el (socks-tests-canned-server-create,
socks-tests-filter-response-parsing-v4): Fix bug in process filter to
prevent prepared outgoing responses from being implicitly encoded as
UTF-8. Fix similar mistake in v4 filter test.
(socks-tests-v4-basic, socks-tests-v5-auth-user-pass,
socks-tests-v5-auth-user-pass-blank, socks-tests-v5-auth-none): Allow
system to choose port instead of hard-coding it.
(socks-tests-perform-hello-world-http-request): Add optional `method'
parameter to specify a gateway method.
(socks-tests-v5-auth-none): Move body to helper function of the same
name.
(socks-override-functions): New test ensuring top-level advice around
`open-networks-stream' still supported. (Bug#53941)
* test/lisp/net/socks-tests.el (auth-registration-and-suite-offer)
(filter-response-parsing-v4, filter-response-parsing-v5): Assert
auth-method selection wrangling and socks-filter parsing.
(v5-auth-user-pass, v5-auth-user-pass-blank, v5-auth-none): Show prep
and execution of the SOCKS connect command and proxying of an HTTP
request; simplify fake server. (Bug#46342)
