[DRE-maint] Bug#1005631: new restriction in rubygems: installing symlink pointing to parent path not allowed - causes ruby-handlebars-assets to ftbfs

[Pirate Praveen]

On Sun, 13 Feb 2022 08:59:18 +0100 Lucas Nussbaum <lucas at debian.org> 
wrote:
 > During a rebuild of all packages in sid, your package failed to build
 > on amd64.
 >
 >
 > Relevant part (hopefully):
 > > make[1]: Entering directory '/<<PKGBUILDDIR>>'
 > > mkdir -p vendor/assets/javascripts
 > > ln -s /usr/share/javascript/handlebars/handlebars.js 
vendor/assets/javascripts/handlebars.js
 > > ln -s 
/usr/share/javascript/handlebars.runtime/handlebars.runtime.js 
vendor/assets/javascripts/handlebars.runtime.js

[...]

 > > Failed to load /dev/null because it doesn't contain valid YAML hash
 > > ERROR:  While executing gem ... (Gem::Package::SymlinkError)
 > >     installing symlink 'vendor/assets/javascripts/handlebars.js' 
pointing to parent path /usr/share/javascript/handlebars/handlebars.js 
of 
/<<PKGBUILDDIR>>/debian/ruby-handlebars-assets/usr/share/rubygems-integration/all/gems/handlebars_assets-0.23.8 
is not allowed

How do we handle this issue? Should we copy instead? If that is the 
solution, we will have to rebuild ruby package whenever the js package 
changes. Can we modify rubygems to allow this link?