Request for a nonexistent php file results in a internal redirect error for network subdomain installs

[bananastalktome]

This is a follow-up to #19796.

In #19796, it looks like the if ( ! $subdomain_install)" check looks like it was removed around the wildcard php file redirect. Thus, in network subdomain installs the htaccess rule to use is shown simply as RewriteRule ^(.*\.php)$ $1 [L]. As a result of this rule, a request for ex/ wp.example.com/this/file/is/invalid.php results in a 500 error after the internal redirect limit is reached. The apache error log shows:

Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary.

It seems that the RewriteRule ^(.*\.php)$ $1 [L] rule (which doesn't actually rewrite anything, since the entire matched pattern becomes the replacement) is matched each time the internal redirect takes place, thus reaching the limit. I am not sure if the subdomain_install check should be added back to prevent this rule from being added in the case of a network subdomain install.

[jeremyfelt]

Closing this and #28164 as duplicates of #20746.