Automatically resolve Git merge conflicts in Rails schema.rb by picking the most recent date in the conflict (works with Rails 6 and recent versions of Git). The following files should be in your home ~ directory.

.gitattributes

db/schema.rb merge=railsschema

.gitconfig

[merge "railsschema"]
  name = Newer Rails schema version
  driver = "ruby -e '\n\
    system %(git), %(merge-file), %(--marker-size=%L), %(%A), %(%O), %(%B)\n\
    b = File.read(%(%A))\n\
    b.sub!(\\A<+ .*\\nActiveRecord::Schema.define.version: ([_0-9]+). do\\n\\|+ .*\\nActiveRecord::Schema.define.version: ([_0-9]+). do\\n=+\\nActiveRecord::Schema.define.version: ([_0-9]+). do\\n>+ .*\\z) do\n\
      %(ActiveRecord::Schema.define(version: #{[$1, $2, $3].max}) do)\n\
    end\n\
    File.open(%(%A), %(w)) {|f| f.write(b)}\n\
    exit 1 if b.include?(%(<)*%L)'"