chore(lsp/tests): diagnostic synchronization (#19264)

Fixes the flaky lsp test by having better synchronization of diagnostics
between the client and server for testing purposes.

1 files changed, 18 insertions, 0 deletions

diff --git a/cli/lsp/lsp_custom.rs b/cli/lsp/lsp_custom.rs
index 70a245a66..24c4bc131 100644
--- a/cli/lsp/lsp_custom.rs
+++ b/cli/lsp/lsp_custom.rs
@@ -10,6 +10,8 @@ pub const TASK_REQUEST: &str = "deno/task";
 pub const RELOAD_IMPORT_REGISTRIES_REQUEST: &str =
   "deno/reloadImportRegistries";
 pub const VIRTUAL_TEXT_DOCUMENT: &str = "deno/virtualTextDocument";
+pub const LATEST_DIAGNOSTIC_BATCH_INDEX: &str =
+  "deno/internalLatestDiagnosticBatchIndex";
 
 // While lsp_types supports inlay hints currently, tower_lsp does not.
 pub const INLAY_HINT: &str = "textDocument/inlayHint";
@@ -44,3 +46,19 @@ impl lsp::notification::Notification for RegistryStateNotification {
 pub struct VirtualTextDocumentParams {
   pub text_document: lsp::TextDocumentIdentifier,
 }
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct DiagnosticBatchNotificationParams {
+  pub batch_index: usize,
+  pub messages_len: usize,
+}
+
+/// This notification is only sent for testing purposes
+/// in order to know what the latest diagnostics are.
+pub enum DiagnosticBatchNotification {}
+
+impl lsp::notification::Notification for DiagnosticBatchNotification {
+  type Params = DiagnosticBatchNotificationParams;
+
+  const METHOD: &'static str = "deno/internalTestDiagnosticBatch";
+}