Fix an external dependency of a ruby gem

Question

I am currently trying to install the gem nfoiled, which provides a ruby interface to ncurses. I do this by using gem install elliottcable-nfoiled as suggest in the README. Downloading it manually from the github repository and then installing it with rake install doesn't work because of a problem with the echoe-gem, thus I am bound to use the normal way.

Unfortunately it depends on the gem ncurses-0.9.1 which is only compatible with ruby 1.8, and thus I can't install nfoiled either (since it always tries to compile ncurses-0.9.1 first):

novavortex:/usr/src# gem install elliottcable-nfoiled
Building native extensions.  This could take a while...
...
form_wrap.c: In function `rbncurs_m_new_form':
form_wrap.c:395: error: `struct RArray' has no member named `len'
form_wrap.c: In function `rbncurs_c_set_field_type':
form_wrap.c:619: error: `struct RArray' has no member named `len'
form_wrap.c: In function `rbncurs_c_set_form_fields':
form_wrap.c:778: error: `struct RArray' has no member named `len'
form_wrap.c: In function `make_arg':
form_wrap.c:1126: error: `struct RArray' has no member named `len'
make: *** [form_wrap.o] Error 1


Gem files will remain installed in /usr/local/lib/ruby/gems/1.9.1/gems/ncurses-0.9.1 for inspection.
Results logged to /usr/local/lib/ruby/gems/1.9.1/gems/ncurses-0.9.1/gem_make.out
novavortex:/usr/src#

I managed to fix the problem in ncurses-0.9.1 (by replacing RARRAY(x)->len with RARRAY_LEN(x)) and to install it, but nfoiled still always tries to recompile it from a freshly downloaded source.

How can I install nfoiled without having it recompile ncurses first?

Answer 1

I was able to install ncurses-ruby it under ruby 1.9.2-head without any problems, I could not install the nfoiled gem because it requires a specific version of echoe.

$ gem install --source http://gems.github.com elliottcable-nfoiled
ERROR:  Error installing elliottcable-nfoiled:
        elliottcable-nfoiled requires ncurses (>= 0, runtime)

$ gem install ncurses
Building native extensions.  This could take a while...
Successfully installed ncurses-0.9.1
1 gem installed
Installing ri documentation for ncurses-0.9.1...
Installing RDoc documentation for ncurses-0.9.1...

$ gem install --source http://gems.github.com elliottcable-nfoiled
ERROR:  Error installing elliottcable-nfoiled:
        elliottcable-nfoiled requires echoe (>= 0, = 3.0.2, runtime)

Are you sure you have the right ncurses development headers so that the ruby bindings build?

Answer 2

You said you already fixed ncurses manually. You can then install the other gem without its dependencies with the --ignore-dependencies switch:

gem install elliottcable-nfoiled --ignore-dependencies