fix(cli-repl): work around Node.js middle-of-line paste bug

Author: addaleax

packages/cli-repl/src/mongosh-repl.spec.ts

@@ -1195,6 +1195,30 @@ describe('MongoshNodeRepl', function () {
         );
       });
     });
+
+    context('pasting code', function () {
+      const pasteStart = '\x1b[200~';
+      const pasteEnd = '\x1b[201~';
+      const moveLeft = '\x1b[1D';
+
+      it('can paste code and run it', async function () {
+        input.write(`${pasteStart}12 * 34${pasteEnd}\n`);
+        await waitEval(bus);
+        expect(output).to.include('408');
+      });
+
+      it('can paste code in the middle of a line and run it', async function () {
+        input.write(`56${moveLeft}${pasteStart}12 * 34${pasteEnd}\n`);
+        await waitEval(bus);
+        expect(output).to.include('177152'); // 512 * 346
+      });
+
+      it('can paste code in the middle of multiline input and run it', async function () {
+        input.write(`{\n56${moveLeft}${pasteStart}12 * 34${pasteEnd}\n}\n`);
+        await waitEval(bus);
+        expect(output).to.include('177152'); // 512 * 346
+      });
+    });
   });
 
   context('with somewhat unreachable history file', function () {

packages/cli-repl/src/mongosh-repl.ts

@@ -47,7 +47,7 @@ import type { FormatOptions } from './format-output';
 import { markTime } from './startup-timing';
 import type { Context } from 'vm';
 import { Script, createContext, runInContext } from 'vm';
-import { installPasteSupport } from './repl-paste-support';
+import { fixNode60446, installPasteSupport } from './repl-paste-support';
 import util from 'util';
 import { fixNodeReplCompleterSideEffectHandling } from './node-repl-fix-completer-side-effects';
 
@@ -278,6 +278,7 @@ class MongoshNodeRepl implements EvaluationListener {
         onAsyncSigint: this.onAsyncSigint.bind(this),
         ...this.nodeReplOptions,
       });
+      fixNode60446(repl);
       context = repl.context;
     } else {
       // https://nodejs.org/api/repl.html#replbuiltinmodules not represented in TS types

packages/cli-repl/src/repl-paste-support.spec.ts

@@ -3,7 +3,7 @@ import { start } from 'repl';
 import type { Readable, Writable } from 'stream';
 import { PassThrough } from 'stream';
 import { tick } from '../test/repl-helpers';
-import { installPasteSupport } from './repl-paste-support';
+import { fixNode60446, installPasteSupport } from './repl-paste-support';
 import { expect } from 'chai';
 
 function createTerminalRepl(extraOpts: Partial<ReplOptions> = {}): {
@@ -22,6 +22,7 @@ function createTerminalRepl(extraOpts: Partial<ReplOptions> = {}): {
     useColors: false,
     ...extraOpts,
   });
+  fixNode60446(repl);
   return { input, output, repl };
 }
 
@@ -49,9 +50,12 @@ describe('installPasteSupport', function () {
     output.read(); // Ignore prompt etc.
     input.write('foo\x1b[Dbar'); // ESC[D = 1 character to the left
     await tick();
-    expect(output.read()).to.equal(
-      'foo\x1B[1D\x1B[1G\x1B[0J> fobo\x1B[6G\x1B[1G\x1B[0J> fobao\x1B[7G\x1B[1G\x1B[0J> fobaro\x1B[8G'
-    );
+    // Expected output changed after https://github.com/nodejs/node/pull/59857
+    // because now characters aren't handled one-by-one anymore.
+    expect(output.read()).to.be.oneOf([
+      'foo\x1B[1D\x1B[1G\x1B[0J> fobo\x1B[6G\x1B[1G\x1B[0J> fobao\x1B[7G\x1B[1G\x1B[0J> fobaro\x1B[8G',
+      'foo\x1B[1Dba\x1B[1G\x1B[0J> fobaro\x1B[8G',
+    ]);
   });
 
   it('ignores control characters in the input while pasting', async function () {
@@ -74,9 +78,10 @@ describe('installPasteSupport', function () {
     output.read();
     input.write('foo\x1b[Dbar');
     await tick();
-    expect(output.read()).to.equal(
-      'foo\x1B[1D\x1B[1G\x1B[0J> foobarfobo\x1B[12G\x1B[1G\x1B[0J> foobarfobao\x1B[13G\x1B[1G\x1B[0J> foobarfobaro\x1B[14G'
-    );
+    expect(output.read()).to.be.oneOf([
+      'foo\x1B[1D\x1B[1G\x1B[0J> foobarfobo\x1B[12G\x1B[1G\x1B[0J> foobarfobao\x1B[13G\x1B[1G\x1B[0J> foobarfobaro\x1B[14G',
+      'foo\x1B[1Dba\x1B[1G\x1B[0J> foobarfobaro\x1B[14G',
+    ]);
   });
 
   it('allows a few special characters while pasting', async function () {

packages/cli-repl/src/repl-paste-support.ts

@@ -1,4 +1,6 @@
-import type { REPLServer } from 'repl';
+import type { Interface as ReadlineInterface } from 'readline';
+import { start as replStart, type REPLServer } from 'repl';
+import { PassThrough } from 'stream';
 
 // https://github.com/nodejs/node/blob/d9786109b2a0982677135f0c146f6b591a0e4961/lib/internal/readline/utils.js#L90
 // https://nodejs.org/api/readline.html#readlineemitkeypresseventsstream-interface
@@ -65,3 +67,67 @@ export function installPasteSupport(repl: REPLServer): string {
   });
   return onEnd;
 }
+
+// Bug: https://github.com/nodejs/node/issues/60446
+// Introduced by: https://github.com/nodejs/node/pull/59857
+// Fixed by: https://github.com/nodejs/node/pull/60470
+function _hasNode60446(): boolean {
+  const input = new PassThrough();
+  const output = new PassThrough();
+  const repl = replStart({ terminal: true, input, output, useColors: false });
+  repl.input.emit('data', '{}');
+  repl.input.emit('keypress', '', { name: 'left' });
+  repl.input.emit('data', 'node');
+  const { line } = repl;
+  repl.close();
+  return line === '{}noed';
+}
+_hasNode60446();
+let hasNode60446: boolean | undefined = undefined;
+
+export function fixNode60446(repl: ReadlineInterface): void {
+  hasNode60446 ??= _hasNode60446();
+  if (!hasNode60446) return;
+  const symbols = [...prototypeChain(repl)].flatMap((proto) =>
+    Object.getOwnPropertySymbols(proto)
+  );
+  const insertStringKey = symbols.find((s) =>
+    String(s).includes('(_insertString)')
+  );
+  const writeToOutputKey = symbols.find((s) =>
+    String(s).includes('(_writeToOutput)')
+  );
+  if (!insertStringKey || !writeToOutputKey) return;
+  const original = (repl as any)[insertStringKey];
+
+  // Monkey-patch in the fix linked above
+  let fixupOnWriteToOutput: undefined | (() => void);
+  Object.defineProperty(repl as any, insertStringKey, {
+    configurable: true,
+    writable: true,
+    enumerable: false,
+    value: function (this: ReadlineInterface, s: string) {
+      if (!(this as any).isCompletionEnabled) {
+        const origLine = this.line;
+        const origCursor = this.cursor;
+        fixupOnWriteToOutput = () => {
+          const beg = origLine.slice(0, origCursor);
+          const end = origLine.slice(origCursor);
+          (this as any).line = beg + s + end;
+        };
+      }
+      return original.call(this, s);
+    },
+  });
+  const originalWriteToOutput = (repl as any)[writeToOutputKey];
+  Object.defineProperty(repl as any, writeToOutputKey, {
+    configurable: true,
+    writable: true,
+    enumerable: false,
+    value: function (this: ReadlineInterface, s: string) {
+      fixupOnWriteToOutput?.();
+      fixupOnWriteToOutput = undefined;
+      return originalWriteToOutput.call(this, s);
+    },
+  });
+}