re-add support for loading aliases in yaml files

Ruby 3.1 includes Psych 4.0 which no longer loads aliases by default.
Since aliases are part of the yaml spec, it seems sensible to re-add
support.

Author: lollipopman

lib/puppet/parser/functions/loadyaml.rb

@@ -49,9 +49,9 @@ module Puppet::Parser::Functions
           warning("Can't load '#{url}' HTTP Error Code: '#{res.status[0]}'")
           args[1]
         end
-        YAML.safe_load(contents) || args[1]
+        YAML.safe_load(contents, aliases: true) || args[1]
       elsif File.exist?(args[0])
-        YAML.load_file(args[0]) || args[1]
+        YAML.load_file(args[0], aliases: true) || args[1]
       else
         warning("Can't load '#{args[0]}' File does not exist!")
         args[1]

spec/functions/loadyaml_spec.rb

@@ -24,7 +24,7 @@
     it "returns 'key' => 'value', 'ķęŷ' => 'νậŀųề', 'キー' => '値'" do
       allow(File).to receive(:exist?).and_call_original
       expect(File).to receive(:exist?).with(filename).and_return(true).once
-      expect(YAML).to receive(:load_file).with(filename).and_return(data).once
+      expect(YAML).to receive(:load_file).with(filename, aliases: true).and_return(data).once
       expect(subject).to run.with_params(filename).and_return(data)
     end
   end
@@ -35,7 +35,7 @@
     it 'filename /tmp/doesexist' do
       allow(File).to receive(:exist?).and_call_original
       expect(File).to receive(:exist?).with(filename).and_return(true).once
-      allow(YAML).to receive(:load_file).with(filename).once.and_raise(StandardError, 'Something terrible have happened!')
+      allow(YAML).to receive(:load_file).with(filename, aliases: true).once.and_raise(StandardError, 'Something terrible have happened!')
       expect(subject).to run.with_params(filename, 'default' => 'value').and_return('default' => 'value')
     end
   end
@@ -48,7 +48,7 @@
 
     it {
       expect(OpenURI).to receive(:open_uri).with(filename, basic_auth).and_return(yaml)
-      expect(YAML).to receive(:safe_load).with(yaml).and_return(data).once
+      expect(YAML).to receive(:safe_load).with(yaml, aliases: true).and_return(data).once
       expect(subject).to run.with_params(filename).and_return(data)
     }
   end
@@ -62,7 +62,7 @@
 
     it {
       expect(OpenURI).to receive(:open_uri).with(url_no_auth, basic_auth).and_return(yaml)
-      expect(YAML).to receive(:safe_load).with(yaml).and_return(data).once
+      expect(YAML).to receive(:safe_load).with(yaml, aliases: true).and_return(data).once
       expect(subject).to run.with_params(filename).and_return(data)
     }
   end
@@ -76,7 +76,7 @@
 
     it {
       expect(OpenURI).to receive(:open_uri).with(url_no_auth, basic_auth).and_return(yaml)
-      expect(YAML).to receive(:safe_load).with(yaml).and_return(data).once
+      expect(YAML).to receive(:safe_load).with(yaml, aliases: true).and_return(data).once
       expect(subject).to run.with_params(filename).and_return(data)
     }
   end
@@ -88,7 +88,7 @@
 
     it {
       expect(OpenURI).to receive(:open_uri).with(filename, basic_auth).and_return(yaml)
-      expect(YAML).to receive(:safe_load).with(yaml).and_raise StandardError, 'Cannot parse data'
+      expect(YAML).to receive(:safe_load).with(yaml, aliases: true).and_raise StandardError, 'Cannot parse data'
       expect(subject).to run.with_params(filename, 'default' => 'value').and_return('default' => 'value')
     }
   end
@@ -103,4 +103,43 @@
       expect(subject).to run.with_params(filename, 'default' => 'value').and_return('default' => 'value')
     }
   end
+
+  context 'when the file contains aliases' do
+    let(:tempfile) { Tempfile.new }
+    let(:filename) { tempfile.path }
+    let(:yaml) do
+      <<~YAML
+        some_numbers: &nums
+          - one
+          - two
+        more_numbers: *nums
+      YAML
+    end
+    let(:data) { { 'some_numbers' => ['one', 'two'], 'more_numbers' => ['one', 'two'] } }
+
+    it 'parses the aliases' do
+      tempfile.write(yaml)
+      tempfile.rewind
+      expect(subject).to run.with_params(filename).and_return(data)
+    end
+  end
+
+  context 'when an URL returns yaml with aliases' do
+    let(:filename) { 'https://example.local/myhash.yaml' }
+    let(:basic_auth) { { http_basic_authentication: ['', ''] } }
+    let(:yaml) do
+      <<~YAML
+        some_numbers: &nums
+          - one
+          - two
+        more_numbers: *nums
+      YAML
+    end
+    let(:data) { { 'some_numbers' => ['one', 'two'], 'more_numbers' => ['one', 'two'] } }
+
+    it {
+      expect(OpenURI).to receive(:open_uri).with(filename, basic_auth).and_return(yaml)
+      expect(subject).to run.with_params(filename).and_return(data)
+    }
+  end
 end