add_query_arg urldecodes passed values but doesn't re-encode them.

It looks fine. I think we should test this, though. Just to make sure "double encoding" works as we want it to.

(In [5193]) Re-encode query values after passed to add_query_arg(). Props mdawaffe. fixes #4084

This ticket urlencodes every argument. Perhaps we should only urlencode those arguments that have passed through parse_str? That would keep things as backward compatible as possible.

What we do now (urlencoding everything, even new arguments) makes the most since but is not backward compatible.

For example, there are a few places in core (and surely plugins too) that do:

add_query_arg( 'foo', urlencode($bar), $url );

That is, the arg is manually urlencoded. Those args will probably now get double encoded with the current code in trunk.

So do we go for a function that works like (I think) it seems like it should, or do we go with a less convenient function that preserves backward compatibility?

Related to #4105 (slash behavior)

I think preserving backwards compatibility is important. Whenever we try to switch something up on plugin authors (even with tons of warning -- *cough* $table* *cough*) isn't a good idea. Considering history.

As long as it works (double encoding/decoding), then I see no reason to fix it further.

(In [5240]) Rollback wonky part of [5193]. see #4084

idea

4084b.diff

Only urlencode()s things that have gone through parse_str().

Hmm. Looks interesting. I'll look at this when I get back later.

(In [5261]) Get add_query_arg() to urlencode all values of parse_str array. Props mdawaffe. fixes #4084

Just so you're aware, this did break another useful function of add_query_arg, which was in easily adding arguments to param style arguments, like for wp_list_pages(). I was using it, for example, to quickly append rewrite rule query entries. So, for those who were doing a similar thing and specifically didn't want things urlencoding, the workaround is to rawurlencode the argument you pass to add_query_arg and then urldecode the whole result.

(In [6064]) Only urlencode previously existing values in add_query_arg() (more backwards compatible). fixes #4935. see #4084. see #4878