ERROR: Failed to build gem native extension.

[Abhay Kumar Verma]

Problem

I'm hated the fact that default Linux package distributor don't update the package quickly enough. So is the case for RUBY. Then I came to think why not kill this problem with Homebrew . And I installed Ruby with Brew which works nice. Not a problem. But recently I got update of RUBY 3.0.0 and problem starts. With the fact I use Ruby with brew. The fiddle need a dependency called ffi and ffi is also served by apt. I don't know much but the problem is ffi.

Expected

The gem should be normally installed without any issue.

Actual

user@machine:~$ gem update
Updating installed gems
Updating fiddle
Building native extensions. This could take a while...
ERROR:  Error installing fiddle:
	ERROR: Failed to build gem native extension.

    current directory: /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.0.0/gems/fiddle-1.0.7/ext/fiddle
/home/linuxbrew/.linuxbrew/opt/ruby/bin/ruby -I /home/linuxbrew/.linuxbrew/Cellar/ruby/3.0.0_1/lib/ruby/3.0.0 -r ./siteconf20210104-8354-iij1al.rb extconf.rb
checking for ffi.h... no
checking for ffi/ffi.h... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
	--with-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/home/linuxbrew/.linuxbrew/Cellar/ruby/3.0.0_1/bin/$(RUBY_BASE_NAME)
	--enable-bundled-libffi
	--disable-bundled-libffi
	--with-libffi-dir
	--without-libffi-dir
	--with-libffi-include
	--without-libffi-include=${libffi-dir}/include
	--with-libffi-lib
	--without-libffi-lib=${libffi-dir}/lib
	--with-libffi-config
	--without-libffi-config
	--with-pkg-config
	--without-pkg-config
	--with-ffi-dir
	--without-ffi-dir
	--with-ffi-include
	--without-ffi-include=${ffi-dir}/include
	--with-ffi-lib
	--without-ffi-lib=${ffi-dir}/lib
extconf.rb:46:in `<main>': missing libffi. Please install libffi. (RuntimeError)

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.0.0/extensions/x86_64-linux/3.0.0/fiddle-1.0.7/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.0.0/gems/fiddle-1.0.7 for inspection.
Results logged to /home/linuxbrew/.linuxbrew/lib/ruby/gems/3.0.0/extensions/x86_64-linux/3.0.0/fiddle-1.0.7/gem_make.out
Gems updated: fiddle

What to do now?
mkmf.log
gem_make.out.log rename due to upload issue.

[Abhay Kumar Verma]

After installing 2 packages everything works.

user@machine:~$ gem install ffi
Fetching ffi-1.14.2.gem
Building native extensions. This could take a while...
Successfully installed ffi-1.14.2
Parsing documentation for ffi-1.14.2
Installing ri documentation for ffi-1.14.2
Done installing documentation for ffi after 7 seconds
1 gem installed
user@machine:~$ sudo apt install libffi-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  libffi-dev
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 57.5 kB of archives.
After this operation, 314 kB of additional disk space will be used.
Get:1 http://in.archive.ubuntu.com/ubuntu groovy/main amd64 libffi-dev amd64 3.4~20200819gead65ca871-0ubuntu3 [57.5 kB]
Fetched 57.5 kB in 0s (130 kB/s)      
Selecting previously unselected package libffi-dev:amd64.
(Reading database ... 206718 files and directories currently installed.)
Preparing to unpack .../libffi-dev_3.4~20200819gead65ca871-0ubuntu3_amd64.deb ...
Unpacking libffi-dev:amd64 (3.4~20200819gead65ca871-0ubuntu3) ...
Setting up libffi-dev:amd64 (3.4~20200819gead65ca871-0ubuntu3) ...
Processing triggers for install-info (6.7.0.dfsg.2-5) ...
Processing triggers for man-db (2.9.3-2) ...

And the gem is now updated.

user@machine:~$ gem update
Updating installed gems
Updating fiddle
Building native extensions. This could take a while...
Successfully installed fiddle-1.0.7
Parsing documentation for fiddle-1.0.7
Installing ri documentation for fiddle-1.0.7
Installing darkfish documentation for fiddle-1.0.7
Done installing documentation for fiddle after 1 seconds
Parsing documentation for fiddle-1.0.7
Done installing documentation for fiddle after 0 seconds
Gems updated: fiddle

In my understanding the ffi gem does nothing and the apt package libffi-dev is necessary for this issue.
Thanks for everything you guys done on this fiddle. You can close this issue, or add this in documentation.

[Sutou Kouhei]

As the error message said, you should have to install libffi-dev by apt:

"extconf.rb:46:in** `<main>': missing libffi. Please install libffi. (RuntimeError)