Empty string is an invalid expression for phpdbg-ev

[rrehbein]

Description

The following series of commands generated the output:

docker run -it --rm php:8.3-cli-alpine phpdbg
[Welcome to phpdbg, the interactive PHP debugger, v8.3.12]
To get help using phpdbg type "help" and press enter
[Please report bugs to <http://bugs.php.net/report.php>]
prompt> ev $e = ''
[Parse Error: syntax error, unexpected input (input string or data), expecting end of command or # (pound sign)]
prompt> ev $e = ""
[Parse Error: syntax error, unexpected input (input string or data), expecting end of command or # (pound sign)]
prompt> ev $e = "e"
e

But I expected this output instead:
The empty strings in an expression for ev in phpdbg should not have triggered a parse-error.

Observed this issue in v8.2.21 as well.

PHP Version

8.3.12

Operating System

No response