Description:
------------
Tested in PHP versions 8.0.2 and 7.4.3.

When phpdbg can not open the given file it fails with the messages:
[Could not open file /missing_file]
[Failed to compile /missing_file, cannot run]

But the exit code is 0, when it should not.

On another hand, when the PHP file exists but has syntax errors it fails with:
[PHP Parse error:  syntax error, unexpected '!', expecting ';' or ',' in /invalid.php on line 3]

If it throws an exception:
[Uncaught Exception in /throw-exception.php on line 3]
Exception: I'm an exception thrown in /throw-exception.php:3
Stack trace:
#0 {main}

In both cases, the exit code is then 255 as expected.

Test script:
---------------
# Tested without Docker in Kubuntu Linux 20.04.2 LTS
phpdbg -qrr missing_file; echo $?
[Could not open file /missing_file]
[Failed to compile /missing_file, cannot run]
0

# Tested in Alpine Linux using Docker
docker run --rm --tty php:cli-alpine phpdbg -qrr missing_file; echo $?
[Could not open file /missing_file]
[Failed to compile /missing_file, cannot run]
0

Expected result:
----------------
A non-zero exit code is expected.

Actual result:
--------------
The exit code is 0.