Zulip URL encoding doesn't work for dots

[camelid]

Rustbot link

https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Use.20sane.20defaults.20in.20x.py.20compiler-team.23326

Actual link

https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/Use.20sane.20defaults.20in.20x.2Epy.20compiler-team.23326

If we compare the Rustbot link (and elaborate the xxx to the full stream name) against the actual link, the only difference that I see is that the actual link encodes the . in x.py as .2E, whereas Rustbot encodes it as just ..

From what I see in the rest of the link, it looks like Zulip encodes special characters as a . and then the ASCII hex code. Because of that, it seems a . must be encoded as its hex code.

Cc #701 (comment)

Cc @Mark-Simulacrum

[camelid]

Relevant code?

triagebot/src/zulip.rs

Lines 337 to 359 in 823fd7f

	// See
	// https://github.com/zulip/zulip/blob/46247623fc279/zerver/lib/url_encoding.py#L9
	// ALWAYS_SAFE without `.` from
	// https://github.com/python/cpython/blob/113e2b0a07c/Lib/urllib/parse.py#L772-L775
	//
	// ALWAYS_SAFE doesn't contain `.` because Zulip actually encodes them to be able
	// to use `.` instead of `%` in the encoded strings
	const ALWAYS_SAFE: &str =
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-~";
	let mut encoded_topic = Vec::new();
	for ch in topic.bytes() {
	if !(ALWAYS_SAFE.contains(ch as char)) {
	write!(encoded_topic, "%{:02X}", ch).unwrap();
	} else {
	encoded_topic.push(ch);
	}
	}
	let mut encoded_topic = String::from_utf8(encoded_topic).unwrap();
	encoded_topic = encoded_topic.replace("%", ".");
	format!("stream/{}-xxx/topic/{}", id, encoded_topic)

[kellda]

Seems fixed since #653

[Mark-Simulacrum]

I would like to add a test, then, just to make sure we don't regress this bit in the future.