Should URL constructors prepend ? when initializing query objects?

[joyeecheung]

This question comes from the Node.js implementation, refs: nodejs/node#11093

The URL constructor specifies:

Set result's query object to a new
{{URLSearchParams}} object using query, and then set that query object's
url object to result

And the URLSearchParams constructor specifies:

If init is given, is a string, and starts with "?", remove the first
code point from init.

But referencing the getter spec of url.search:

Return "?", followed by context object's url's query.

one can infer that the query of an url should not have the leading ?, this means:

1. The URL constructor would pass an query with leading ? stripped to new URLSearchParams
2. The new URLSearchParams would strip a leading ? again, in any, but the WPT tests expect ??a=b&c=d to be serialized as %3Fa=b&c=d

AFAICT the URL constructor should prepend a ? here, if we don't introduce a special way to notify the URLSearchParams constructor not to strip the leading ?:

diff --git a/url.bs b/url.bs
index 7988aa2..f1a9c9d 100644
--- a/url.bs
+++ b/url.bs
@@ -2648,7 +2648,8 @@ when invoked, must run these steps:
  <li><p>Set <var>result</var>'s <a for=URL>url</a> to <var>parsedURL</var>.

  <li><p>Set <var>result</var>'s <a for=URL>query object</a> to a <a for=URLSearchParams>new</a>
- {{URLSearchParams}} object using <var>query</var>, and then set that <a for=URL>query object</a>'s
+ {{URLSearchParams}} object using <var>query</var> prepended with the
+ leading <code>?</code>, and then set that <a for=URL>query object</a>'s
  <a for=URLSearchParams>url object</a> to <var>result</var>.

  <li><p>Return <var>result</var>.

Also the definition of url.query in 4.1. URL representation can be a little bit more explicit about the leading ?. I can put up a PR if this is confirmed.

[TimothyGu]

"A new URLSearchParams object" doesn't invoke the constructor (which performs the stripping of ?), but instead goes to the specialized algorithm that skips the ?-stripping step. It is a bug in the Node.js implementation for using the constructor in such a fashion.

[joyeecheung]

Thanks for the clarification, I missed out the concept-urlsearchparams-new part. I think this can be closed now.