From 199ca9c78be3ceb7d8d49329ea28ff75e53d979e Mon Sep 17 00:00:00 2001 From: Justin Burnham Date: Tue, 24 Sep 2013 10:57:15 -0700 Subject: (#20200) Add a recursive merge function. Issue #20200 notes that the merge function does not support nested hashes. To prevent unintended side effects with changing merge, add a deep_merge function instead. --- lib/puppet/parser/functions/deep_merge.rb | 44 +++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 lib/puppet/parser/functions/deep_merge.rb (limited to 'lib/puppet/parser/functions/deep_merge.rb') diff --git a/lib/puppet/parser/functions/deep_merge.rb b/lib/puppet/parser/functions/deep_merge.rb new file mode 100644 index 0000000..94677b8 --- /dev/null +++ b/lib/puppet/parser/functions/deep_merge.rb @@ -0,0 +1,44 @@ +module Puppet::Parser::Functions + newfunction(:deep_merge, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args| + Recursively merges two or more hashes together and returns the resulting hash. + + For example: + + $hash1 = {'one' => 1, 'two' => 2, 'three' => { 'four' => 4 } } + $hash2 = {'two' => 'dos', 'three' => { 'five' => 5 } } + $merged_hash = deep_merge($hash1, $hash2) + # The resulting hash is equivalent to: + # $merged_hash = { 'one' => 1, 'two' => 'dos', 'three' => { 'four' => 4, 'five' => 5 } } + + When there is a duplicate key that is a hash, they are recursively merged. + When there is a duplicate key that is not a hash, the key in the rightmost hash will "win." + + ENDHEREDOC + + if args.length < 2 + raise Puppet::ParseError, ("deep_merge(): wrong number of arguments (#{args.length}; must be at least 2)") + end + + deep_merge = Proc.new do |hash1,hash2| + hash1.merge!(hash2) do |key,old_value,new_value| + if old_value.is_a?(Hash) && new_value.is_a?(Hash) + deep_merge.call(old_value, new_value) + else + new_value + end + end + end + + result = Hash.new + args.each do |arg| + next if arg.is_a? String and arg.empty? # empty string is synonym for puppet's undef + # If the argument was not a hash, skip it. + unless arg.is_a?(Hash) + raise Puppet::ParseError, "deep_merge: unexpected argument type #{arg.class}, only expects hash arguments" + end + + deep_merge.call(result, arg) + end + return( result ) + end +end -- cgit v1.2.3