Move empty diagnostics workaround back into the server

crates/rust-analyzer/src/main_loop.rs

@@ -328,8 +328,33 @@ impl GlobalState {
                 }
 
                 let uri = file_id_to_url(&self.vfs.read().0, file_id);
-                let diagnostics =
+                let mut diagnostics =
                     self.diagnostics.diagnostics_for(file_id).cloned().collect::<Vec<_>>();
+
+                // VSCode assumes diagnostic messages to be non-empty strings, so we need to patch
+                // empty diagnostics. Neither the docs of VSCode nor the LSP spec say whether
+                // diagnostic messages are actually allowed to be empty or not and patching this
+                // in the VSCode client does not work as the assertion happens in the protocol
+                // conversion. So this hack is here to stay, and will be considered a hack
+                // until the LSP decides to state that empty messages are allowed.
+
+                // See https://github.com/rust-lang/rust-analyzer/issues/11404
+                // See https://github.com/rust-lang/rust-analyzer/issues/13130
+                let patch_empty = |message: &mut String| {
+                    if message.is_empty() {
+                        *message = " ".to_string();
+                    }
+                };
+
+                for d in &mut diagnostics {
+                    patch_empty(&mut d.message);
+                    if let Some(dri) = &mut d.related_information {
+                        for dri in dri {
+                            patch_empty(&mut dri.message);
+                        }
+                    }
+                }
+
                 let version = from_proto::vfs_path(&uri)
                     .map(|path| self.mem_docs.get(&path).map(|it| it.version))
                     .unwrap_or_default();

editors/code/src/client.ts

@@ -99,22 +99,6 @@ export async function createClient(
         traceOutputChannel: traceOutputChannel(),
         outputChannel: outputChannel(),
         middleware: {
-            async handleDiagnostics(uri, diagnostics, next) {
-                // Workaround for https://github.com/microsoft/vscode/issues/155531
-                for (const diagnostic of diagnostics) {
-                    if (!diagnostic.message) {
-                        diagnostic.message = " ";
-                    }
-                    if (diagnostic.relatedInformation) {
-                        for (const relatedInformation of diagnostic.relatedInformation) {
-                            if (!relatedInformation.message) {
-                                relatedInformation.message = " ";
-                            }
-                        }
-                    }
-                }
-                next(uri, diagnostics);
-            },
             async provideHover(
                 document: vscode.TextDocument,
                 position: vscode.Position,