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authorJustin Burnham <jburnham@mediatemple.net>2013-09-24 10:57:15 -0700
committerJosh Partlow <joshua.partlow@puppetlabs.com>2013-10-29 12:22:49 -0700
commit199ca9c78be3ceb7d8d49329ea28ff75e53d979e (patch)
treee54a1cc1e713776d69d90f4ea502d48daa25bfca /lib
parentae4f52e9e5db1a97ad77b159f11fdbd7ddbad3dd (diff)
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(#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.
Diffstat (limited to 'lib')
-rw-r--r--lib/puppet/parser/functions/deep_merge.rb44
1 files changed, 44 insertions, 0 deletions
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