Fix frozen string literal issue (#27)

Author: chaadow

.github/workflows/ci.yml

@@ -12,5 +12,21 @@ permissions:
   contents: read
 
 jobs:
-  Shared:
-    uses: fog/.github/.github/workflows/ci.yml@v1.4.0
+  test:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        ruby-version: ['3.0', '3.1', '3.2', '3.3', 'head']
+    continue-on-error: ${{ matrix.ruby-version == 'head' }}
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby-version }}
+        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
+    - name: Run tests
+      run: bundle exec rake RUBYOPT="--enable-frozen-string-literal"

lib/fog/parsers/base.rb

@@ -18,7 +18,7 @@ def reset
       end
 
       def characters(string)
-        @value ||= ''
+        @value ||= +''
         @value << string
       end
 

lib/fog/to_hash_document.rb

@@ -5,20 +5,22 @@ def initialize
     end
 
     def characters(string)
-      @value ||= ""
+      @value ||= +''
       @value << string.strip
     end
 
     def end_element(name)
       last = @stack.pop
-      if last.empty? && @value.empty?
-        @stack.last[name.to_sym] = ""
+      @stack.push({}) if @stack.empty?
+
+      if last&.empty? && @value.empty?
+        @stack.last[name.to_sym] = +''
       elsif last == { :i_nil => "true" }
         @stack.last[name.to_sym] = nil
       elsif !@value.empty?
         @stack.last[name.to_sym] = @value
       end
-      @value = ""
+      @value = +''
     end
 
     def body
@@ -30,7 +32,7 @@ def response
     end
 
     def start_element(name, attributes = [])
-      @value = ""
+      @value = +''
       parsed_attributes = {}
       until attributes.empty?
         if attributes.first.is_a?(Array)

lib/fog/xml/response.rb

@@ -4,7 +4,7 @@ class Response
       def initialize(parser)
         @parser = parser
         @data_stream = Nokogiri::XML::SAX::PushParser.new(parser)
-        @response_string = ""
+        @response_string = +''
       end
 
       def call(chunk, _remaining, _total)
@@ -14,7 +14,7 @@ def call(chunk, _remaining, _total)
 
       def rewind
         @parser.reset
-        @response_string = ""
+        @response_string = +''
       end
 
       def finish

spec/fog/to_hash_document_spec.rb

@@ -0,0 +1,142 @@
+# frozen_string_literal: true
+
+require 'minitest_helper'
+require 'fog/xml'
+
+# We expose accessors just for testing purposes
+Fog::ToHashDocument.attr_accessor(:value, :stack)
+
+describe Fog::ToHashDocument do
+  before do
+    @document = Fog::ToHashDocument.new
+  end
+
+  describe '#characters' do
+    it 'appends characters to @value' do
+      @document.characters('some text')
+      _(@document.value).must_equal 'some text'
+    end
+
+    it 'strips whitespace from characters' do
+      @document.characters('  some text  ')
+      _(@document.value).must_equal 'some text'
+    end
+  end
+
+  describe '#end_element' do
+    before do
+      @document.stack << {}
+      @document.characters('some text')
+    end
+
+    it 'adds element with text content to the stack' do
+      @document.end_element('element')
+
+      expected = { element: 'some text' }
+      _(@document.stack.last).must_equal(expected)
+    end
+
+    it 'can mutate the new empty value' do
+      @document.end_element('element')
+
+      _(@document.value).must_equal('')
+
+      # Mutate the new empty value even when frozen string literals are enabled
+      _(@document.characters('one'))
+    end
+
+    it 'adds empty string if element is empty and value is empty' do
+      @document.value = ''
+
+      @document.end_element('element')
+
+      expected = { element: '' }
+      _(@document.stack.last).must_equal(expected)
+    end
+
+    it 'adds nil if element has :i_nil attribute' do
+      @document.stack.last[:i_nil] = 'true'
+      @document.value = ''
+
+      @document.end_element('element')
+
+      expected = { element: nil }
+      _(@document.stack.last).must_equal(expected)
+    end
+  end
+
+  describe '#body' do
+    it 'returns the first element of the stack' do
+      @document.stack << { key: 'value' }
+
+      expected = { key: 'value' }
+      _(@document.body).must_equal(expected)
+    end
+  end
+
+  describe '#response' do
+    it 'returns the body' do
+      @document.stack << { key: 'value' }
+
+      expected = { key: 'value' }
+      _(@document.response).must_equal(expected)
+    end
+  end
+
+  describe '#start_element' do
+    it 'parses attributes correctly' do
+      @document.start_element('element', [%w[key value]])
+
+      expected = { key: 'value' }
+      _(@document.stack.last).must_equal(expected)
+    end
+
+    it 'handles elements without attributes' do
+      @document.start_element('element')
+
+      _(@document.stack.last).must_equal({})
+    end
+
+    it 'adds nested elements to the stack' do
+      @document.start_element('parent')
+      @document.start_element('child')
+
+      _(@document.stack).must_equal([{ child: {} }, { child: {} }, {}])
+    end
+
+    it 'adds nested elements with attributes to the stack' do
+      @document.start_element('parent')
+      @document.start_element('child', [%w[key value]])
+      expected = [
+        { child: { key: 'value' } },
+        { child: { key: 'value' } },
+        { key: 'value' }
+      ]
+
+      _(@document.stack).must_equal(expected)
+    end
+
+    it 'handles multiple children elements correctly' do
+      @document.start_element('parent')
+      @document.start_element('child1')
+      @document.end_element('child1')
+      @document.start_element('child2', [%w[key value]])
+      @document.end_element('child2')
+      expected = {
+        child1: '',
+        child2: { key: 'value' }
+      }
+
+      _(@document.stack.first).must_equal(expected)
+    end
+
+    it 'handles text content within elements' do
+      @document.start_element('parent')
+      @document.characters('some text')
+      @document.end_element('parent')
+
+      expected = { parent: 'some text' }
+      _(@document.stack.first).must_equal(expected)
+    end
+  end
+end