Fix undo cursor jumps and formatting

src/app/displayable.ts

@@ -17,8 +17,8 @@ export abstract class Displayable {
     private shortcuts = new Map<string, KeyHandler>();
 
     constructor() {
-        // Attempt to install handlers shortly after construction. If `dom` is not
+        // Attempt to install handlers shortly after construction.
-        // available yet, retry a few times.
+        // If `dom` is not available yet, retry a few times.
         setTimeout(() => this.installHandlers(0), 0);
 
         // Add general shortcuts

src/app/filestate.ts

@@ -167,10 +167,7 @@ export class OpenFile implements WorkspaceFile {
         this.rootState.val = transaction.state;
 
         if (transaction.changes && !transaction.changes.empty) {
-            if (this.changes === undefined) {
+            this.changeSet = this.changes.compose(transaction.changes);
-                this.changes = ChangeSet.empty(this.rootState.val.doc.length);
-            }
-            this.changes = this.changes.compose(transaction.changes);
         }
 
         if (origin) {
@@ -178,7 +175,12 @@ export class OpenFile implements WorkspaceFile {
             es.forEach((e) => e.dispatch(e.view.state.update(trs), true));
         } else {
             this.editors.forEach((e) => {
-                e.dispatch(e.view.state.update(trs), true);
+                const changes = transaction.changes;
+                const userEvent = transaction.annotation(Transaction.userEvent);
+                const annotations = userEvent
+                    ? [Transaction.userEvent.of(userEvent)]
+                    : [];
+                e.dispatch(e.view.state.update({ changes, annotations }), true);
             });
         }
     }
@@ -203,8 +205,16 @@ export class OpenFile implements WorkspaceFile {
     get languageId(): string {
         return inferLanguageFromPath(this.filePath.val || "") || "";
     }
+
     doc: Text;
-    changes: ChangeSet;
+    private changeSet: ChangeSet;
+    get changes(): ChangeSet {
+        if (!this.changeSet) {
+            this.changeSet = ChangeSet.empty(this.rootState.val.doc.length);
+        }
+        return this.changeSet;
+    }
+
     // Return an EditorView to be used by the LSP Workspace for position mapping.
     // If `main` is provided and belongs to this open file, return it. Otherwise
     // return the first available editor view, or null if none exist.

src/app/lsp/diagnostics.ts

@@ -1,52 +1,76 @@
-import type * as lsp from "vscode-languageserver-protocol"
+import type * as lsp from "vscode-languageserver-protocol";
-import {ViewPlugin, ViewUpdate} from "@codemirror/view"
+import { ChangeSet } from "@codemirror/state";
-import {LSPPlugin, LSPClientExtension} from "@codemirror/lsp-client"
+import { ViewPlugin, ViewUpdate } from "@codemirror/view";
-import {OpenFile} from "../filestate"
+import { LSPPlugin, LSPClientExtension } from "@codemirror/lsp-client";
-import { Text } from "@codemirror/state"
+import { OpenFile } from "../filestate";
+import { Text } from "@codemirror/state";
 
 function toSeverity(sev: lsp.DiagnosticSeverity) {
-  return sev == 1 ? "error" : sev == 2 ? "warning" : sev == 3 ? "info" : "hint"
+    return sev == 1
+        ? "error"
+        : sev == 2
+          ? "warning"
+          : sev == 3
+            ? "info"
+            : "hint";
 }
 
-const autoSync = ViewPlugin.fromClass(class {
+const autoSync = ViewPlugin.fromClass(
-  pending: any | null = null
+    class {
+        pending: any | null = null;
         update(update: ViewUpdate) {
             if (update.docChanged) {
-      if (this.pending != null) clearTimeout(this.pending)
+                if (this.pending != null) clearTimeout(this.pending);
                 this.pending = setTimeout(() => {
-        this.pending = null
+                    this.pending = null;
-        const plugin = LSPPlugin.get(update.view)
+                    const plugin = LSPPlugin.get(update.view);
-        if (plugin) plugin.client.sync()
+                    if (plugin) plugin.client.sync();
-      }, 500)
+                }, 500);
             }
         }
         destroy() {
-    if (this.pending != null) clearTimeout(this.pending)
+            if (this.pending != null) clearTimeout(this.pending);
         }
-})
+    },
+);
 
 function fromPosition(doc: Text, pos: lsp.Position): number {
-  const line = doc.line(pos.line + 1)
+    const line = doc.line(pos.line + 1);
-  return line.from + pos.character
+    return line.from + pos.character;
 }
 
 export function serverDiagnostics(): LSPClientExtension {
     return {
-    clientCapabilities: {textDocument: {publishDiagnostics: {versionSupport: true}}},
+        clientCapabilities: {
+            textDocument: { publishDiagnostics: { versionSupport: true } },
+        },
         notificationHandlers: {
-      "textDocument/publishDiagnostics": (client, params: lsp.PublishDiagnosticsParams) => {
+            "textDocument/publishDiagnostics": (
+                client,
+                params: lsp.PublishDiagnosticsParams,
+            ) => {
                 const file = client.workspace.getFile(params.uri) as OpenFile;
-        if (!file || params.version != null && params.version != file.version) return false;
+                if (!file) {
-        const mapPos = (p: number) => file.changes ? file.changes.mapPos(p) : p;
+                    return false;
-        file.setDiagnostics(params.diagnostics.map(item => ({
+                }
-          from: mapPos(fromPosition(file.doc, item.range.start)),
+                if (params.version != null && params.version != file.version) {
-          to: mapPos(fromPosition(file.doc, item.range.end)),
+                    return false;
+                }
+                file.setDiagnostics(
+                    params.diagnostics.map((item) => ({
+                        from: file.changes.mapPos(
+                            fromPosition(file.doc, item.range.start),
+                        ),
+                        to: file.changes.mapPos(
+                            fromPosition(file.doc, item.range.end),
+                        ),
                         severity: toSeverity(item.severity ?? 1),
                         message: item.message,
-        })));
+                    })),
-        return true
+                );
-      }
+                return true;
             },
-    editorExtension: autoSync
+        },
-  }
+        editorExtension: autoSync,
+    };
 }

src/main/langserver.ts

@@ -86,7 +86,9 @@ function ensureLspForKey(
             const len = parseInt(m[1], 10);
             const totalLen = headerEnd + 4 + len;
             if (entry.buffer.length < totalLen) break; // wait for more
-            const body = entry.buffer.subarray(headerEnd + 4, totalLen).toString();
+            const body = entry.buffer
+                .subarray(headerEnd + 4, totalLen)
+                .toString();
             // Forward body to all attached ports
             try {
                 entry.ports.forEach((p) => {