1 files changed, 39 insertions, 0 deletions
diff --git a/_plugins/lint-hook.rb b/_plugins/lint-hook.rb
new file mode 100644
index 0000000..6d883cd
--- /dev/null
+++ b/_plugins/lint-hook.rb
@@ -0,0 +1,39 @@
+require 'set'
+
+IGNORED_PAGES = Set['site.json', 'sitemap.xml']
+
+module Jekyll
+  class Linter < Generator
+    safe true
+    @@known_ids = Set[]
+
+    def insert_id(name, document)
+      lang = document.data['lang']
+      ref = document.data['ref']
+      id = "#{name}:#{lang}:#{ref}"
+      if @@known_ids.include? id then
+        raise "Duplicate ID found: '#{id}'"
+      else
+        @@known_ids.add id
+      end
+    end
+
+    def assert_unique_ids(site)
+      site.collections.each do |name, collection|
+        collection.docs.each do |document|
+          insert_id name, document
+        end
+      end
+
+      site.pages.each do |page|
+        unless IGNORED_PAGES.include? page.path
+          insert_id 'page', page
+        end
+      end
+    end
+
+    def generate(site)
+      assert_unique_ids(site)
+    end
+  end
+end