Extension file regression in Ubuntu 24.04

[fusivack]

After upgrading to Ubuntu 24.04.1, noticed that the "open" action (hitting enter) on certain files does not do anything, while others work. After some debugging, it seems that sections in "~/.config/mc/mc.ext.ini" that are regexp based are the ones doing nothing, whereas shell based ones are working as expected.

Edit ~/.config/mc/mc.ext.ini file to reproduce:

Section not working (misc.sh script is not called)

[markdown]
Regex=\.mk?d$
RegexIgnoreCase=true
Open=/usr/lib/mc/ext.d/misc.sh open md

Section working (misc.sh script is called)

[markdown]
Shell=.md
ShellIgnoreCase=true
Open=/usr/lib/mc/ext.d/misc.sh open md

System info

GNU Midnight Commander 4.8.30
Built with GLib 2.80.0
Built with S-Lang 2.3.3 with terminfo database
Built with libssh2 1.11.0
With builtin Editor and Aspell support
With subshell support as default
With support for background operations
With mouse support on xterm and Linux console
With support for X11 events
With internationalization support
With multiple codepages support
With ext2fs attributes support
Virtual File Systems:
 cpiofs, tarfs, sfs, extfs, ext2undelfs, ftpfs, sftpfs, fish
Data types:
 char: 8; int: 32; long: 64; void *: 64; size_t: 64; off_t: 64;

[System data]
    Config directory: /etc/mc/
    Data directory:   /usr/share/mc/
    File extension handlers: /usr/lib/mc/ext.d/
    VFS plugins and scripts: /usr/lib/mc/
        extfs.d:        /usr/lib/mc/extfs.d/
        fish:           /usr/lib/mc/fish/

[User data]
    Config directory: /home/tank/.config/mc/
    Data directory:   /home/tank/.local/share/mc/
        skins:          /home/tank/.local/share/mc/skins/
        extfs.d:        /home/tank/.local/share/mc/extfs.d/
        fish:           /home/tank/.local/share/mc/fish/
        mcedit macros:  /home/tank/.local/share/mc/mc.macros
        mcedit external macros: /home/tank/.local/share/mc/mcedit/macros.d/macro.*
    Cache directory:  /home/tank/.cache/mc/
 '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--disable-option-checking' '--libdir=${prefix}/lib/x86_64-linux-gnu' '--runstatedir=/run' '--disable-maintainer-mode' '--disable-dependency-tracking' 'AWK=awk' 'X11_WWW=x-www-browser' '--libexecdir=/usr/lib' '--with-x' '--with-screen=slang' '--disable-rpath' '--disable-static' '--disable-silent-rules' '--enable-aspell' '--enable-vfs-sftp' '--enable-vfs-undelfs' '--enable-tests' 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -ffile-prefix-map=/build/mc-3Q0Rbi/mc-4.8.30=. -flto=auto -ffat-lto-objects -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -fdebug-prefix-map=/build/mc-3Q0Rbi/mc-4.8.30=/usr/src/mc-3:4.8.30-1build2' 'LDFLAGS=-Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -Wl,-z,relro -Wl,-z,now -Wl,--as-needed' 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=3'

The documentation mentions that PCRE lib is used for regexes. The following packages are installed

libpcre2-16-0/noble,now 10.42-4ubuntu2 amd64 [installed,automatic]
libpcre2-8-0/noble,now 10.42-4ubuntu2 amd64 [installed]
libpcre3/noble,now 2:8.39-15build1 amd64 [installed]

$ ldd /usr/bin/mc
        linux-vdso.so.1 (0x00007fffc7ff5000)
        libslang.so.2 => /lib/x86_64-linux-gnu/libslang.so.2 (0x0000727570a00000)
        libgpm.so.2 => /lib/x86_64-linux-gnu/libgpm.so.2 (0x0000727570e6d000)
        libe2p.so.2 => /lib/x86_64-linux-gnu/libe2p.so.2 (0x0000727570e62000)
        libssh2.so.1 => /lib/x86_64-linux-gnu/libssh2.so.1 (0x0000727570e1a000)
        libext2fs.so.2 => /lib/x86_64-linux-gnu/libext2fs.so.2 (0x0000727570db0000)
        libgmodule-2.0.so.0 => /lib/x86_64-linux-gnu/libgmodule-2.0.so.0 (0x00007275709f9000)
        libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007275708b0000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x0000727570600000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x0000727570517000)
        libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x0000727570894000)
        libcrypto.so.3 => /lib/x86_64-linux-gnu/libcrypto.so.3 (0x0000727570000000)
        libcom_err.so.2 => /lib/x86_64-linux-gnu/libcom_err.so.2 (0x000072757088e000)
        libpcre2-8.so.0 => /lib/x86_64-linux-gnu/libpcre2-8.so.0 (0x000072756ff66000)
        /lib64/ld-linux-x86-64.so.2 (0x0000727570fe0000)

[andrew_b]

Fixed in #4502 (mc-4.8.31).