Fix parsing erb with bare yield (#2444)

Earlopain · web-flow · commit e18d4565c073 · 2024-08-14T17:31:38.000+01:00
Parse erb documents in an eval context Some things that are valid in erb would not be valid in a standalone ruby file. This particularly impacts `yield`. Instead treat the provided code as being evaled Closes #2442
diff --git a/lib/ruby_lsp/erb_document.rb b/lib/ruby_lsp/erb_document.rb
@@ -12,7 +12,8 @@ def parse
       @needs_parsing = false
       scanner = ERBScanner.new(@source)
       scanner.scan
-      @parse_result = Prism.parse(scanner.ruby)
+      # assigning empty scopes to turn Prism into eval mode
+      @parse_result = Prism.parse(scanner.ruby, scopes: [[]])
     end
 
     sig { override.returns(T::Boolean) }
diff --git a/test/erb_document_test.rb b/test/erb_document_test.rb
@@ -23,6 +23,27 @@ def test_erb_file_is_properly_parsed
     )
   end
 
+  def test_erb_file_parses_in_eval_context
+    document = RubyLsp::ERBDocument.new(source: +<<~ERB, version: 1, uri: URI("file:///foo.erb"))
+      <html>
+        <head>
+          <%= yield :head %>
+        </head>
+        <body>
+          <%= yield %>
+        </body>
+      </html>
+    ERB
+
+    document.parse
+
+    refute_predicate(document, :syntax_error?)
+    assert_equal(
+      "      \n        \n        yield :head   \n         \n        \n        yield   \n         \n       \n",
+      document.parse_result.source.source,
+    )
+  end
+
   def test_erb_document_handles_windows_newlines
     document = RubyLsp::ERBDocument.new(source: "<%=\r\nbar %>", version: 1, uri: URI("file:///foo.erb"))
     document.parse
