From 8caeede0eee42b29882c3e52b1d2b1751e626273 Mon Sep 17 00:00:00 2001
From: krassowski <5832902+krassowski@users.noreply.github.com>
Date: Sun, 18 Jun 2023 21:44:25 +0100
Subject: [PATCH] Support optional `.virtual_documents`

Cherry-picked from https://github.com/jupyter-lsp/jupyterlab-lsp/pull/930
---
 packages/lsp/src/connection_manager.ts | 31 +++++++++++++++++---------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/packages/lsp/src/connection_manager.ts b/packages/lsp/src/connection_manager.ts
index cd1f684a117a..d5c5f953c3dd 100644
--- a/packages/lsp/src/connection_manager.ts
+++ b/packages/lsp/src/connection_manager.ts
@@ -547,20 +547,16 @@ export namespace DocumentConnectionManager {
     virtualDocument: VirtualDocument,
     language: string
   ): IURIs | undefined {
-    const { settings } = Private.getLanguageServerManager();
-    const wsBase = settings.wsUrl;
+    const serverManager = Private.getLanguageServerManager();
+    const wsBase = serverManager.settings.wsUrl;
     const rootUri = PageConfig.getOption('rootUri');
     const virtualDocumentsUri = PageConfig.getOption('virtualDocumentsUri');
 
-    const baseUri = virtualDocument.hasLspSupportedFile
-      ? rootUri
-      : virtualDocumentsUri;
-
     // for now take the best match only
-    const matchingServers =
-      Private.getLanguageServerManager().getMatchingServers({
-        language
-      });
+    const serverOptions: ILanguageServerManager.IGetServerIdOptions = {
+      language
+    };
+    const matchingServers = serverManager.getMatchingServers(serverOptions);
     const languageServerId =
       matchingServers.length === 0 ? null : matchingServers[0];
 
@@ -568,6 +564,21 @@ export namespace DocumentConnectionManager {
       return;
     }
 
+    const specs = serverManager.getMatchingSpecs(serverOptions);
+    const spec = specs.get(languageServerId);
+    if (!spec) {
+      console.warn(
+        `Specification not available for server ${languageServerId}`
+      );
+    }
+    const requiresOnDiskFiles = spec?.requires_documents_on_disk ?? true;
+    const supportsInMemoryFiles = !requiresOnDiskFiles;
+
+    const baseUri =
+      virtualDocument.hasLspSupportedFile || supportsInMemoryFiles
+        ? rootUri
+        : virtualDocumentsUri;
+
     // workaround url-parse bug(s) (see https://github.com/jupyter-lsp/jupyterlab-lsp/issues/595)
     let documentUri = URLExt.join(baseUri, virtualDocument.uri);
     if (