Additional incremental tweaks

My previous incremental change wasn't quite right, and causes files that are not currently opened to never be reloaded. This corrects that change by only skipping file changed on disk events when the file is opened by vscode, meaning that it has an active TextDocument that will be triggered for changes.

Author: 333fred

src/features/changeForwarding.ts

@@ -49,17 +49,24 @@ function forwardFileChanges(server: OmniSharpServer): IDisposable {
                 return;
             }
 
-            if (changeType === FileChangeType.Change && uri.fsPath.endsWith(".cs")) {
-                // When a file changes on disk a FileSystemEvent is generated as well as
-                // a DidChangeTextDocumentEvent. The OmniSharp server listens for Change events
-                // for ".cs" files and reloads their text from disk. This creates a situation where the server
-                // may have updated the document to reflect disk and also recieves a set of TextChanges
-                // to apply to the document. In order to avoid that situation, we will not send Change events
-                // for ".cs" files and instead allow them to be updated via the DidChangeTextDocumentEvent.
+            const docs = workspace.textDocuments.filter(doc => doc.uri.fsPath === uri.fsPath);
+            if (Array.isArray(docs) && docs.some(doc => !doc.isClosed)) {
+                // When a file changes on disk a FileSystemEvent is generated as well as a
+                // DidChangeTextDocumentEvent.The ordering of these is:
+                //  1. This method is called back. vscode's TextDocument has not yet been reloaded, so it has
+                //     the version from before the changes are applied.
+                //  2. vscode reloads the file, and fires onDidChangeTextDocument. The document has been updated,
+                //     and the changes have the delta.
+                // If we send this change to the server, then it will reload from the disk, which means it will
+                // be synchronized to the version after the changes. Then, onDidChangeTextDocument will fire and
+                // send the delta changes, which will cause the server to apply those exact changes. The results
+                // being that the file is now in an inconsistent state.
+                // If the document is closed, however, it will no longer be synchronized, so the text change will
+                // not be triggered and we should tell the server to reread from the disk.
                 return;
             }
 
-            let req = { FileName: uri.fsPath, changeType };
+            const req = { FileName: uri.fsPath, changeType };
 
             serverUtils.filesChanged(server, [req]).catch(err => {
                 console.warn(`[o] failed to forward file change event for ${uri.fsPath}`, err);
@@ -75,7 +82,7 @@ function forwardFileChanges(server: OmniSharpServer): IDisposable {
             }
 
             if (changeType === FileChangeType.Delete) {
-                let requests = [{ FileName: uri.fsPath, changeType: FileChangeType.DirectoryDelete }];
+                const requests = [{ FileName: uri.fsPath, changeType: FileChangeType.DirectoryDelete }];
 
                 serverUtils.filesChanged(server, requests).catch(err => {
                     console.warn(`[o] failed to forward file change event for ${uri.fsPath}`, err);