Fail to build with Ruby 4.0.0_preview2

[sergiodj]

Hi there,

I'm trying to build your gem with the latest preview for the upcoming Ruby 4.0 release, and it's currently failing with:

# gem install sqlite3
Building native extensions. This could take a while...
ERROR:  Error installing sqlite3:
        ERROR: Failed to build gem native extension. 

    current directory: /usr/lib/ruby/gems/4.0.0+0/gems/sqlite3-2.8.1/ext/sqlite3                
/usr/bin/ruby extconf.rb                                                                                                                                                                                           
Building sqlite3-ruby using packaged sqlite3.                                                            
*** 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
        --without-opt-dir
        --with-opt-include=${opt-dir}/include
        --without-opt-include
        --with-opt-lib=${opt-dir}/lib
        --without-opt-lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/usr/bin/$(RUBY_BASE_NAME)
        --help
        --download-dependencies
        --with-sqlcipher
        --without-sqlcipher
        --with-sqlcipher-dir
        --without-sqlcipher-dir
        --with-sqlcipher-include
        --without-sqlcipher-include
        --with-sqlcipher-lib
        --without-sqlcipher-lib
        --enable-system-libraries
        --disable-system-libraries
        --with-sqlcipher
        --without-sqlcipher
        --with-sqlcipher-dir
        --without-sqlcipher-dir
        --with-sqlcipher-include
        --without-sqlcipher-include
        --with-sqlcipher-lib
        --without-sqlcipher-lib
        --with-sqlite-source-dir
        --with-sqlite-cflags
        --without-sqlite-cflags
extconf.rb:73:in 'File.join': no implicit conversion of nil into String (TypeError)

          unless File.exist?(File.join(recipe.target, recipe.host, recipe.name, recipe.version))
                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        from extconf.rb:73:in 'block in Sqlite3::ExtConf.configure_packaged_libraries'
        from extconf.rb:51:in 'Kernel#tap'
        from extconf.rb:51:in 'Sqlite3::ExtConf.configure_packaged_libraries'
        from extconf.rb:17:in 'Sqlite3::ExtConf.configure'
        from extconf.rb:297:in '<main>'

extconf failed, exit code 1

Gem files will remain installed in /usr/lib/ruby/gems/4.0.0+0/gems/sqlite3-2.8.1 for inspection.
Results logged to /usr/lib/ruby/gems/4.0.0+0/extensions/x86_64-linux-gnu/4.0.0+0/sqlite3-2.8.1/gem_make.out

Please let me know if you need more info and I'll be happy to provide.

Thanks.

[flavorjones]

I'm able to install this gem with Ruby 4.0.0-preview2 fine, and the CI pipeline continuously runs against Ruby head. My results:

$ uname -a
Linux bepi 6.17.9-arch1-1 #1 SMP PREEMPT_DYNAMIC Mon, 24 Nov 2025 15:21:09 +0000 x86_64 GNU/Linux

$ ruby -v
ruby 4.0.0preview2 (2025-11-17 master 4fa6e9938c) +PRISM [x86_64-linux]

$ gem install sqlite3-ruby
Fetching mini_portile2-2.8.9.gem
Fetching sqlite3-ruby-1.3.3.gem
Fetching sqlite3-2.8.1.gem
Successfully installed mini_portile2-2.8.9
Building native extensions. This could take a while...
Successfully installed sqlite3-2.8.1

#######################################################

Hello! The sqlite3-ruby gem has changed it's name to just sqlite3.  Rather than
installing `sqlite3-ruby`, you should install `sqlite3`.  Please update your
dependencies accordingly.

Thanks from the Ruby sqlite3 team!

<3 <3 <3 <3

#######################################################

Successfully installed sqlite3-ruby-1.3.3
3 gems installed

Some things that would help diagnose:

• describe your system -- operating system, architecture, etc.
• include the output of gem env
• include the output of bundle env
• show the full contents of your mkmf.log file
• include the full contents of gem_make.out

If you can reproduce this in a standard docker container, that would be extremely helpful.