Kind of a big deal for us, as we don't want the same file used every time - we use %t to create a separate file for each request.

Also, not working for %u.

%r works, so we can use that for now and then use file modification date to determining timing.

The root cause is that the %t and %u modifiers created file names in the form of '/tmp/cachegrind.out._tmp_foo_php.2020-12-02 18:19:57_081116' ­— instead of using the epoch seconds, it did create a textual string. Because on Windows you can't have files with ":" in it, it then failed to create the file.

I am curious to know though whether the log file (which you have commented out) would included a warning about not being able to create the file. Could you have a look at that please, by making sure your php.ini has "xdebug.log=c:\xdebug.log" and then running:

php -r 'xdebug_info();'

The log file should contain a warning, and the output of the script that you ran as well (it might scroll of your screen).

This is now fixed in the Git repository through https://github.com/xdebug/xdebug/pull/702 — I'm still interested in the output in the log, if there is any.