Send ERB virtual state when a document is opened

lib/ruby_lsp/server.rb

@@ -413,6 +413,21 @@ def text_document_did_open(message)
           ),
         )
       end
+
+      # Documents are parsed on creation, so the virtual state would otherwise only be sent after the first edit
+      if document.is_a?(ERBDocument) && @global_state.client_capabilities.supports_request_delegation
+        send_message(
+          Notification.new(
+            method: "delegate/textDocument/virtualState",
+            params: {
+              textDocument: {
+                uri: text_document[:uri].to_s,
+                text: document.host_language_source,
+              },
+            },
+          ),
+        )
+      end
     end
 
     #: (Hash[Symbol, untyped] message) -> void

test/server_test.rb

@@ -1779,6 +1779,28 @@ def test_does_not_crash_when_a_document_uri_cannot_be_parsed
     server&.run_shutdown
   end
 
+  def test_did_open_sends_the_virtual_state_of_erb_documents
+    @server.global_state.apply_options({ capabilities: { experimental: { requestDelegation: true } } })
+    uri = URI("file:///foo.html.erb")
+
+    @server.process_message({
+      method: "textDocument/didOpen",
+      params: {
+        textDocument: {
+          uri: uri,
+          text: "<div><%= foo %></div>",
+          version: 1,
+          languageId: "erb",
+        },
+      },
+    })
+
+    notification = find_message(RubyLsp::Notification, "delegate/textDocument/virtualState")
+    document = @server.instance_variable_get(:@store).get(uri)
+    assert_equal(uri.to_s, notification.params[:textDocument][:uri])
+    assert_equal(document.host_language_source, notification.params[:textDocument][:text])
+  end
+
   private
 
   def run_initialize_server_with_setup_error(error)