Semdiff

Semantic differences for Ruby code changes.

Transforms Prism AST nodes to canonical forms whenever possible, for example: constant folding and reordering operands in expressions based on type signatures (YARD or RBS).

Uses GumTree/difftastic to generate the diff on canonical ASTs.

Install the gem and add to the application's Gemfile by executing:

bundle add semdiff

If bundler is not being used to manage dependencies, install the gem by executing:

gem install semdiff

Invoke with 2 target files and the semdiff executable, for example:

semdiff --yard --gumtree --diff-original test/assets/yard/before.rb test/assets/yard/after.rb

All options:

Usage: semdiff [options] BEFORE.rb AFTER.rb

Specific options:
    -h, --help                       Prints this help
    -o, --output-directory TARGET    Directory to output normalized unparsed files (default temporary)
        --ignore-comments            Don't process and preserve comments in the unparsed files
        --check-only                 Report whether there are any changes, but don't calculate them (much faster).
        --diff-original              Show a diff of the original files above the normalized files
        --yard [TARGET]              Use YARD (optional existing directory, default reparses input files)
        --yard-files FILE1,FILE2,... Reparse specific YARD files (choose --yard or this, not both)
        --rbs [TARGET]               Use RBS signatures (default ./sig/)
        --gumtree                    Use gumtree webdiff after default difftastic
        --skip-difftastic            Skip difftastic text diff

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/tesorion/semdiff.