fix: required parameters placed after missing optional parameters are no longer skipped

[glennsayers]

Due to multiple matching routes, exec is called for [[param1=required]]/[param2=param2]/[param3] even though we’ve provided 3 parameters which should correlate to the /[param2=param2]/[param3]/[param4] route.

The code flow was finishing with a buffer size of 0, which was incorrectly telling Kit that the route was a match. As such it wasn't attempting to parse other routes to check for a match, despite the fact there was still a required parameter that hadn't been matched.

This situation doesn’t appear to be covered under current unit tests as the tests load one route at a time. I've added a new Playwright test to cover this scenario.

Fixes #9304

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[dummdidumm]

Thank you! Can you turn this into a unit test? I believe you can get the same outcome if you test that the route in question is not matched (by setting expected: undefined)

[glennsayers]

Sure @dummdidumm ! Do you want me to keep the playwright test or replace it?

[dummdidumm]

replace them

[Rich-Harris]

Thank you! Happy the fix turned out to be so simple

[benmccann]

fyi, this needed to be patch. releases are failing because this is an invalid value: #9365