(MODULES-3568) Move dig to dig44 and deprecate dig

A new version of dig was introduced in Puppet 4.5.0 that
isn't compatible with the stdlib version of dig. To maintain
backwards compatibility and ensure that tests for stdlib aren't
broken, this patch renames dig to dig44 and adds a deprecation
warning to the stdlib dig function.

5 files changed, 152 insertions, 52 deletions

diff --git a/README.markdown b/README.markdown
index 373b08c..1368b2f 100644
--- a/README.markdown
+++ b/README.markdown
@@ -295,6 +295,8 @@ Returns the difference between two arrays. The returned array is a copy of the o
 
 #### `dig`
 
+DEPRECATED: This function has been replaced in Puppet 4.5.0, use dig44() for backwards compatibility or use the new version.
+
 *Type*: rvalue.
 
 Retrieves a value within multiple layers of hashes and arrays via an array of keys containing a path. The function goes through the structure by each path component and tries to return the value at the end of the path.
@@ -329,6 +331,42 @@ $value = dig($data, ['a', 'b', 'c', 'd'], 'not_found')
 3. **'not_found'** The default value. It will be returned if nothing is found.
    (optional, defaults to *undef*)
 
+#### `dig44`
+
+*Type*: rvalue.
+
+Retrieves a value within multiple layers of hashes and arrays via an array of keys containing a path. The function goes through the structure by each path component and tries to return the value at the end of the path.
+
+In addition to the required path argument, the function accepts the default argument. It is returned if the path is not correct, if no value was found, or if any other error has occurred.
+
+~~~ruby
+$data = {
+  'a' => {
+    'b' => [
+      'b1',
+      'b2',
+      'b3',
+    ]
+  }
+}
+
+$value = dig44($data, ['a', 'b', 2])
+# $value = 'b3'
+
+# with all possible options
+$value = dig44($data, ['a', 'b', 2], 'not_found')
+# $value = 'b3'
+
+# using the default value
+$value = dig44($data, ['a', 'b', 'c', 'd'], 'not_found')
+# $value = 'not_found'
+~~~
+
+1. **$data** The data structure we are working with.
+2. **['a', 'b', 2]** The path array.
+3. **'not_found'** The default value. It will be returned if nothing is found.
+   (optional, defaults to *undef*)
+
 #### `dirname`
 
 Returns the `dirname` of a path. For example, `dirname('/path/to/a/file.ext')` returns '/path/to/a'. *Type*: rvalue.
diff --git a/lib/puppet/parser/functions/dig.rb b/lib/puppet/parser/functions/dig.rb
index a9aa770..34fa701 100644
--- a/lib/puppet/parser/functions/dig.rb
+++ b/lib/puppet/parser/functions/dig.rb
@@ -4,51 +4,13 @@
 
 module Puppet::Parser::Functions
   newfunction(:dig, :type => :rvalue, :doc => <<-EOS
-Looks up into a complex structure of arrays and hashes and returns nil
-or the default value if nothing was found.
-
-Path is an array of keys to be looked up in data argument. The function
-will go down the structure and try to extract the required value.
-
-$data = {
-  'a' => {
-    'b' => [
-      'b1',
-      'b2',
-      'b3' ]}}
-
-$value = dig($data, ['a', 'b', '2'], 'not_found')
-=> $value = 'b3'
-
-a -> first hash key
-b -> second hash key
-2 -> array index starting with 0
-
-not_found -> (optional) will be returned if there is no value or the path
-did not match. Defaults to nil.
-
-In addition to the required "path" argument, "dig" accepts default
-argument. It will be returned if no value was found or a path component is
-missing. And the fourth argument can set a variable path separator.
+    DEPRECATED: This function has been replaced in Puppet 4.5.0, please use dig44() for backwards compatibility or use the new version.
     EOS
-             ) do |arguments|
-    # Two arguments are required
-    raise(Puppet::ParseError, "dig(): Wrong number of arguments " +
-                              "given (#{arguments.size} for at least 2)") if arguments.size < 2
-
-    data, path, default = *arguments
-
-    if !(data.is_a?(Hash) || data.is_a?(Array))
-      raise(Puppet::ParseError, "dig(): first argument must be a hash or an array, " <<
-                                "given #{data.class.name}")
+  ) do |arguments|
+    warning("dig() DEPRECATED: This function has been replaced in Puppet 4.5.0, please use dig44() for backwards compatibility or use the new version.")
+    if ! Puppet::Parser::Functions.autoloader.loaded?(:dig44)
+      Puppet::Parser::Functions.autoloader.load(:dig44)
     end
-
-    unless path.is_a? Array
-      raise(Puppet::ParseError, "dig(): second argument must be an array, " <<
-                                "given #{path.class.name}")
-    end
-
-    value = path.reduce(data) { |h, k| (h.is_a?(Hash) || h.is_a?(Array)) ? h[k] : break }
-    value.nil? ? default : value
+    function_dig44(arguments)
   end
 end
diff --git a/lib/puppet/parser/functions/dig44.rb b/lib/puppet/parser/functions/dig44.rb
new file mode 100644
index 0000000..a7de363
--- /dev/null
+++ b/lib/puppet/parser/functions/dig44.rb
@@ -0,0 +1,56 @@
+#
+# dig44.rb
+#
+
+module Puppet::Parser::Functions
+  newfunction(:dig44, :type => :rvalue, :doc => <<-EOS
+DEPRECATED: This function has been replaced in puppet 4.5.0.
+
+Looks up into a complex structure of arrays and hashes and returns nil
+or the default value if nothing was found.
+
+Path is an array of keys to be looked up in data argument. The function
+will go down the structure and try to extract the required value.
+
+$data = {
+  'a' => {
+    'b' => [
+      'b1',
+      'b2',
+      'b3' ]}}
+
+$value = dig44($data, ['a', 'b', '2'], 'not_found')
+=> $value = 'b3'
+
+a -> first hash key
+b -> second hash key
+2 -> array index starting with 0
+
+not_found -> (optional) will be returned if there is no value or the path
+did not match. Defaults to nil.
+
+In addition to the required "path" argument, "dig44" accepts default
+argument. It will be returned if no value was found or a path component is
+missing. And the fourth argument can set a variable path separator.
+    EOS
+             ) do |arguments|
+    # Two arguments are required
+    raise(Puppet::ParseError, "dig44(): Wrong number of arguments " +
+                              "given (#{arguments.size} for at least 2)") if arguments.size < 2
+
+    data, path, default = *arguments
+
+    if !(data.is_a?(Hash) || data.is_a?(Array))
+      raise(Puppet::ParseError, "dig44(): first argument must be a hash or an array, " <<
+                                "given #{data.class.name}")
+    end
+
+    unless path.is_a? Array
+      raise(Puppet::ParseError, "dig44(): second argument must be an array, " <<
+                                "given #{path.class.name}")
+    end
+
+    value = path.reduce(data) { |h, k| (h.is_a?(Hash) || h.is_a?(Array)) ? h[k] : break }
+    value.nil? ? default : value
+  end
+end
diff --git a/spec/functions/dig44_spec.rb b/spec/functions/dig44_spec.rb
new file mode 100644
index 0000000..fd451ff
--- /dev/null
+++ b/spec/functions/dig44_spec.rb
@@ -0,0 +1,44 @@
+require 'spec_helper'
+
+describe 'dig44' do
+  it "should exist" do
+    expect(Puppet::Parser::Functions.function("dig44")).to eq("function_dig44")
+  end
+
+  it "should raise a ParseError if there are less than 2 arguments" do
+    expect { scope.function_dig44([]) }.to raise_error(Puppet::ParseError)
+  end 
+
+  it "should raise a ParseError if the first argument isn't a hash or array" do
+    expect { scope.function_dig44(['bad', []]) }.to raise_error(Puppet::ParseError)
+  end 
+
+  it "should raise a ParseError if the second argument isn't an array" do
+    expect { scope.function_dig44([{}, 'bad']) }.to raise_error(Puppet::ParseError)
+  end
+
+  it "should return an empty hash when given empty parameters" do
+    result = scope.function_dig44([{}, []])
+    expect(result).to(eq({}))
+  end
+
+  it "should return value when given simple hash" do
+    result = scope.function_dig44([{"a" => "b"}, ["a"]])
+    expect(result).to(eq("b"))
+  end
+
+  it "should find hash values two levels deep" do
+    result = scope.function_dig44([{"a" => {"b" => "c"}}, ["a", "b"]])
+    expect(result).to(eq("c"))
+  end
+
+  it "should return default value if nothing was found" do
+    result = scope.function_dig44([{}, ["a", "b"], "d"])
+    expect(result).to(eq("d"))
+  end
+
+  it "should work on booleans as well as strings" do
+    result = scope.function_dig44([{"a" => false}, ["a"]])
+    expect(result).to(eq(false))
+  end
+end
diff --git a/spec/functions/dig_spec.rb b/spec/functions/dig_spec.rb
index 1c5d49d..ad16fdd 100644
--- a/spec/functions/dig_spec.rb
+++ b/spec/functions/dig_spec.rb
@@ -1,13 +1,13 @@
 require 'spec_helper'
 
 describe 'dig' do
-  it { is_expected.to run.with_params().and_raise_error(Puppet::ParseError) }
-  it { is_expected.to run.with_params('bad', []).and_raise_error(Puppet::ParseError) }
-  it { is_expected.to run.with_params({}, 'bad').and_raise_error(Puppet::ParseError) }
 
-  it { is_expected.to run.with_params({}, []).and_return({}) }
-  it { is_expected.to run.with_params({"a" => "b"}, ["a"]).and_return("b") }
-  it { is_expected.to run.with_params({"a" => {"b" => "c"}}, ["a", "b"]).and_return("c") }
-  it { is_expected.to run.with_params({}, ["a", "b"], "d").and_return("d") }
-  it { is_expected.to run.with_params({"a" => false}, ["a"]).and_return(false) }
+  it "should exist" do
+    expect(Puppet::Parser::Functions.function("dig")).to eq("function_dig")
+  end
+
+  it "should give a deprecation warning when called" do
+    scope.expects(:warning).with("dig() DEPRECATED: This function has been replaced in Puppet 4.5.0, please use dig44() for backwards compatibility or use the new version.")
+    scope.function_dig([{}, []])
+  end
 end