June 2018 Archives

The Problem: my MT Blog was refusing to load the CMS because of software bit-rot.

More Detail: If I try to go to the CMS page I get this (Obviously, as is proud tradition here, all system output happens on striped fanfold paper):

"Got an error: Unescaped left brace in regex is illegal 
here in regex; marked by <-- HERE in m/{{ <-- HERE theme_static
}}/?/"

What's causing this? In Perl 5.22, unescaped left braces are flagged as a warning, however in 5.26 (The current version as of writing), these are flagged as errors. As Moveable Type Open Source (MTOS)is no longer updated, there is no hope that this will ever be fixed.

To solve this problem in the short term, I could just fix the Regexes that are causing the issues and not share the fixes. This would solve the problem for me, and at least allow me to post to the site, etc. This is a good short term fix, but obviously there would be no further upgrades or new plugins, etc. This is what I've done for the short term.

The changes are fairly straightforward. All that's needed is to escape the left braces in the file lib/MT/App/CMS.pm on line 4978. It's probably best to escape all the braces. Escaping the braces just means that the line goes from:

$css =~ s#{{theme_static}}/?#$theme->static_file_url#ie;

to

$css =~ s#\{\{theme_static\}\}/?#$theme->static_file_url#ie;

In addition, a version of perl::YAML::Syck installed clashed with the system install. (This generally happens when a CPAN install conflicts with a packag-manager install.) This looks like this in the /var/log/httpd/error_log:

Syck.c: loadable library and perl binaries are mismatched 
(got handshake key 0xdb80080, needed 0xde00080)

$ sudo dnf remove perl-YAML-Syck
$ sudo updatedb
$ locate Syck
# now delete it from anywhere it is remaining in the system
$ sudo rm -rf /usr/local/lib64/perl5/auto/YAML/Syck
$ sudo rm -rf /usr/local/lib64/perl5/YAML
$ sudo rm -rf /usr/local/lib64/perl5/JSON
$ sudo rm -rf /usr/local/share/man/man3/JSON\:\:Syck.3pm 
$ sudo rm -rf /usr/local/share/man/man3/YAML\:\:Syck.3pm 

MT comes with it's own version of YAML::Syck, packaged as MT::Util::YAML::Syck, so there was no need to reinstall the perl-YAML-Syck system package.

Longer term solution probably involve migrating to Wordpress from MovableType. Wordpress is actively developed as an open source solution, so that's a better option for the future.