fix: 2 sections can't have the same id

lib/maglev/errors.rb

@@ -4,6 +4,7 @@ module Maglev
   module Errors
     class NotAuthorized < StandardError; end
     class UnknownSection < StandardError; end
+    class DuplicateSectionDefinition < StandardError; end
 
     class UnknownSetting < StandardError
       def initialize(section_id, block_id, setting_id)

lib/maglev/theme_filesystem_loader.rb

@@ -11,6 +11,7 @@ def initialize(fetch_section_screenshot_path)
     def call(path)
       theme = add(YAML.safe_load(File.read(path.join('theme.yml')), aliases: true))
       sections = load_sections(theme, Pathname.new(path).join('sections/**/*.yml'))
+      detect_duplicate_sections(sections)
       theme.sections = Maglev::Section::Store.new(sections)
       theme
     rescue Errno::ENOENT
@@ -52,6 +53,12 @@ def find_section_screenshot_timestamp(theme, section)
       File.exist?(path) ? File.mtime(path).to_i : nil
     end
 
+    def detect_duplicate_sections(sections)
+      sections.group_by(&:id).each do |id, list|
+        raise Maglev::Errors::DuplicateSectionDefinition, "Duplicate section definition: #{id}" if list.size > 1
+      end
+    end
+
     def log_missing_theme_file(path)
       # don't log the error if the ruby code is not executed inside
       # the Rails console or when the Rails server is running

spec/fixtures/themes/theme_with_sections_with_same_id/sections/category_1/section_a.yml

@@ -0,0 +1,30 @@
+# Name of the section displayed in the editor UI
+name: Section A
+
+category: category_1
+
+# Definition of the settings:
+# A setting type can be one of the following values: text, image, checkbox, link and color.
+# Please visit: https://docs.maglev.dev/concepts/setting for more explanation.
+settings:
+- label: "Title"
+  id: title
+  type: text
+  default: "Title"
+  # html: true
+  # line_break: true
+
+- label: "Body"
+  id: body
+  type: text
+  html: true
+  line_break: true
+  default: "Body"
+
+# Definition of the blocks.
+# You can define as many types of blocks as you want.
+blocks: []
+
+# By default, in the editor UI, blocks will be listed below the "Content" title.
+# The title can be changed with the following property:
+# blocks_label: "My list of items"

spec/fixtures/themes/theme_with_sections_with_same_id/sections/category_2/section_a.yml

@@ -0,0 +1,23 @@
+# Name of the section displayed in the editor UI
+name: Section A
+
+category: category_2
+
+# Definition of the settings:
+# A setting type can be one of the following values: text, image, checkbox, link and color.
+# Please visit: https://docs.maglev.dev/concepts/setting for more explanation.
+settings:
+- label: "Title"
+  id: title
+  type: text
+  default: "Title"
+  # html: true
+  # line_break: true
+
+# Definition of the blocks.
+# You can define as many types of blocks as you want.
+blocks: []
+
+# By default, in the editor UI, blocks will be listed below the "Content" title.
+# The title can be changed with the following property:
+# blocks_label: "My list of items"

spec/fixtures/themes/theme_with_sections_with_same_id/theme.yml

@@ -0,0 +1,10 @@
+id: default
+name: Default
+
+section_categories:
+- id: category_1
+  name: "Category #1"
+- id: category_2
+  name: "Category #2"
+
+style_settings: []

spec/lib/maglev/theme_filesystem_loader_spec.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Maglev::ThemeFilesystemLoader do
+  describe '#call' do
+    # rubocop:disable Lint/UnusedBlockArgument
+    let(:fetch_section_screenshot_path) { ->(theme:, section:, absolute:) { path } }
+    # rubocop:enable Lint/UnusedBlockArgument
+
+    subject { described_class.new(fetch_section_screenshot_path).call(Pathname.new(path)) }
+
+    context 'There are 2 sections with the same id in different categories' do
+      let(:path) { File.expand_path('./spec/fixtures/themes/theme_with_sections_with_same_id') }
+
+      it 'raises a DuplicateSectionDefinition error' do
+        expect { subject }.to raise_error(Maglev::Errors::DuplicateSectionDefinition)
+      end
+    end
+  end
+end