How to compare keys in yaml files?

Question

There are two ruby on rails internationalization yaml files. One file is complete and another one is with missing keys. How can I compare two yaml files and see missing keys in

Answer 1

Assuming file1 is the proper version and file2 is the version with missing keys:

def compare_yaml_hash(cf1, cf2, context = [])
  cf1.each do |key, value|

    unless cf2.key?(key)
      puts "Missing key : #{key} in path #{context.join(".")}" 
      next
    end

    value2 = cf2[key]
    if (value.class != value2.class)
      puts "Key value type mismatch : #{key} in path #{context.join(".")}" 
      next
    end

    if value.is_a?(Hash)
      compare_yaml_hash(value, value2, (context + [key]))  
      next
    end

    if (value != value2)
      puts "Key value mismatch : #{key} in path #{context.join(".")}" 
    end    
  end
end

Now

compare_yaml_hash(YAML.load_file("file1"), YAML.load_file("file2"))

Limitation: Current implementation should be extended to support arrays if your YAML file contains arrays.

Answer 2

differz compares two YAML files and prints missing keys in the second file.

It comes both as a library and as a command-line tool. You can install the latter with gem install differz.

Answer 3

I wanted to extract the diff to have something to work with, and the snippet here just prints stuff. So my version returns a hash with diff. It's structure mirrors the original hashes, but the values are descriptions of the differences.

def deep_hash_diff(hash1, hash2, hash1_name = 'Hash 1', hash2_name = 'Hash 2')
  diff = {}
  (hash1.keys - hash2.keys).each do |key1|
    diff[key1] = "Present in #{hash1_name}, but not in #{hash2_name}"
  end
  (hash2.keys - hash1.keys).each do |key2|
    diff[key2] = "Present in #{hash2_name}, but not in #{hash1_name}"
  end

  (hash1.keys & hash2.keys).each do |common_key|
    if hash1[common_key].is_a?(Hash)
      if hash2[common_key].is_a?(Hash)
        res = deep_hash_diff(hash1[common_key], hash2[common_key], hash1_name, hash2_name)
        diff[common_key] = res if res.present?
      else
        diff[common_key] = "#{hash1_name} has nested hash, but #{hash2_name} just value #{hash2[common_key]}"
      end
    elsif hash2[common_key].is_a?(Hash)
      diff[common_key] = "#{hash2_name} has nested hash, but #{hash1_name} just value #{hash1[common_key]}"
    end
  end
  diff
end

I've then used it pretty much as:

res = deep_hash_diff(YAML.load_file("en.yml"), YAML.load_file("spa.yml"), 'English translation', 'Spanish translation')
puts(res.to_yaml) # for nicer output

Answer 4

I couldn't find a fast tool to do that. I decided to write my own tool for this.

You can install it with cabal:

$ cabal update
$ cabal install yamlkeysdiff

Then you can diff two files this way:

$ yamlkeysdiff file1.yml file2.yml
> missing key in file2
< missing key in file1

You can also compare two subsets of the files:

$ yamlkeysdiff "file1.yml#key:subkey" "file2.yml#otherkey"

It behaves exactly like diff, you can do this:

$ yamlkeysdiff file1.yml file2.yml && echo Is the same || echo Is different