Is it possible to force the %-encoding of +?

[grahamc]

• Note that this crate implements the URL Standard not RFC 1738 or RFC 3986

(but I'm hoping ...)

Describe the bug

This code sample, which is clearly standards-correct behavior emits https://example.com/foo+bar:

let mut url = Url::parse("https://example.com/").unwrap();
url.path_segments_mut().unwrap().push("foo+bar");
    
println!("{}", url);

However, some systems like AWS S3 incorrectly interpret +'s in the path to be spaces:

$ curl 'https://xxx.s3.amazonaws.com/v0.15.1+xxx/xxx'
<?xml version="1.0" encoding="UTF-8"?>
<Error>
  <Code>NoSuchKey</Code>
  <Message>The specified key does not exist.</Message>. 
  <Key>v0.15.1 xxx/xxx</Key>
  ...
</Error>

S3 does decode a %2B as a +, like I'm hoping for.

This puts me in a pickle about how to do this. If I url-encode the + before passing it to URL, it gets (again, properly) encoded to %252B, but S3 doesn't understand that obviously.

Is there a way to get the behavior I'm looking for? Would I have to get the path implement my own string replacement of + with %2B?

[valenting]

It seems the issue only happens when using path_segments_mut because of the code here.
I think % was added to PATH_SEGMENT & SPECIAL_PATH_SEGMENT to prevent you from setting the path to %2e which is not allowed.
let x = url::Url::parse("https://example.com/foo%2bbar"); works as expected.