bug#55957: 29.0.50; Jdb incorrectly parses empty classpath

[pva-outdoor]

Hello, team!

Please take a look into gud.el function (gud-jdb-marker-filter):

 2461   (if (and gud-jdb-use-classpath
 2462            (not gud-jdb-classpath-string)
 2463            (or (string-match "classpath:[ \t[]+\\([^]]+\\)" 
gud-marker-acc)
                                              ^^^^^^^^^^^^^^^^^^               
 2464                (string-match "-classpath[ \t\"]+\\([^ \"]+\\)" 
gud-marker-acc)))
 
The highlighted regexp incorrectly matches the text:

Set deferred uncaught java.lang.Throwable
Initializing jdb ...
> base directory: /
classpath: []

The regexp captures opening `[' into (match-string 1). Possibly the regexp
may be corrected with "classpath:[ \t[]+\\([^]]*\\)" to avoid this.
                                              ^^^

Best regards,
Andrey Petrov.



In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.34, cairo 
version 1.17.6)
 of 2022-06-09 built on perm05-pva.itgroup.local
Repository revision: 39d2efbfae1dc081258a764f3c47f5f492f38fec
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Arch Linux

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JSON LCMS2 LIBOTF LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY
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WEBP X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB

Important settings:
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Major mode: Fundamental

Minor modes in effect:
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Load-path shadows:
None found.

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Memory information:
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