What is causing this completely bizarre behavior with mod_rewrite?

Question

Here is my rule:

RewriteRule ^user/(\d+)$ rewrite.php?id=$1

This redirects, but $_GET['id'] is not set. If I change the above rule to:

RewriteRule ^anything/(\d+)$ rewrite.php?id=$1

It works. Why does one work but not the other?

Here is more information:

• There is no directory named user
• The only other .htaccess file in the hierarchy is blank.
• anything can be replaced by anything other than user.

Update: I checked the rewritelog and it's empty.

Answer 1

I finally found the cause of the problem... Apparently (and this is documented nowhere that I could find) if you have a file (in this case, PHP) with the same name as the first virtual directory the rewrite rule doesn't work. (Redirect loops, missing parameters, etc.)

For example, the following rule:

#RewriteRule ^user/(\d+)$ user.php?id=$1 [L]

Will malfunction if there is a file named user.php in the same directory as the PHP file.