MIGRATED: Fix accidental double-escaping when Router.UseEncodedPath() is enabled

[tebruno99]

MIGRATED
Original PR: @nvx gorilla#641

Fixes gorilla#354
Fixes #10

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Bug originally mentioned in gorilla#354 (comment)

Summary of Changes

When Router.UseEncodedPath() is enabled (and SkipClean is not enabled), a request to http://localhost/foo/../bar%25 causes a redirect to http://localhost/bar%2525 as there is a bug where this code path results in double-encoding (the % from the %25 is itself encoded as %25, resulting in %2525).

The expected output for this should have been a redirect to http://localhost/bar%25. A unit test for this behaviour has been added which originally failed with the following output:

Expected redirect location to http://localhost/bar%25, found http://localhost/bar%2525
The remaining changes allows the new unit test to pass and does not break any existing unit tests.

[nvx]

I note this isn't merged into the main branch. Is there a plan for this (and presumably the other similar PRs)?

Are you guys looking at maintaining gorilla mux going forward?

[tebruno99]

I note this isn't merged into the main branch. Is there a plan for this (and presumably the other similar PRs)?

Are you guys looking at maintaining gorilla mux going forward?

I pulled in all the original PRs into their own branches here so that I could test and familiarize myself with the code base and changes before merging the PRs to main. I was not previously a mux contributor so this will take a little time. I hope to either accept or reject the migrated PRs by mid Jan '23 after some time over the holidays reviewing.

The intent is to maintain mux & accept community contributions when they align well with general usage, etc. Eventually, if need or want to also start new feature development.

[brusMX]

@tebruno99 are there any updates to get this merged into main?