repl: fix infinite loop caused by indentation preservation

The editorMode's indentation preservation feature causes an infinite
loop in certain cases when using the REPL's .load feature. This commit
adds a variable to keep track of whether load is used and disables the
indentation preservation in this case.

lib/repl.js

@@ -855,7 +855,8 @@ function REPLServer(prompt,
     cmd = cmd || '';
     sawSIGINT = false;
 
-    if (self.editorMode) {
+    // Preserve indentation in editorMode
+    if (self.editorMode && !self.loadMode) {
       self[kBufferedCommandSymbol] += cmd + '\n';
 
       // code alignment
@@ -1779,9 +1780,11 @@ function defineDefaultCommands(repl) {
         const stats = fs.statSync(file);
         if (stats && stats.isFile()) {
           _turnOnEditorMode(this);
+          this.loadMode = true;
           const data = fs.readFileSync(file, 'utf8');
           this.write(data);
           _turnOffEditorMode(this);
+          this.loadMode = false;
           this.write('\n');
         } else {
           this.output.write(
@@ -1790,6 +1793,7 @@ function defineDefaultCommands(repl) {
         }
       } catch {
         this.output.write(`Failed to load: ${file}\n`);
+        this.loadMode = false;
       }
       this.displayPrompt();
     }

test/parallel/test-repl-load-and-execute.js

@@ -0,0 +1,48 @@
+'use strict';
+const common = require('../common');
+const ArrayStream = require('../common/arraystream');
+const assert = require('assert');
+const join = require('path').join;
+const fs = require('fs');
+
+common.skipIfDumbTerminal();
+
+const tmpdir = require('../common/tmpdir');
+tmpdir.refresh();
+
+const terminalCode = '\u001b[1G\u001b[0J \u001b[1G';
+const terminalCodeRegex = new RegExp(terminalCode.replace(/\[/g, '\\['), 'g');
+
+const repl = require('repl');
+
+const inputStream = new ArrayStream();
+const outputStream = new ArrayStream();
+
+const r = repl.start({
+  prompt: '',
+  input: inputStream,
+  output: outputStream,
+  terminal: true,
+  useColors: false
+});
+
+const testFile = 'function a(b) {\n  return b }\na(1)\n';
+const testFileName = join(tmpdir.path, 'foo.js');
+fs.writeFileSync(testFileName, testFile);
+
+const command = `.load ${testFileName}\n`;
+let accum = '';
+outputStream.write = (data) => accum += data.replace('\r', '');
+
+
+// load test file.
+r.write('.editor\n');
+r.write(command);
+
+const expected = command +
+'function a(b) {\n' +
+'  return b }\n' +
+'a(1)\n' +
+'1\n';
+assert.strictEqual(accum.replace(terminalCodeRegex, ''), expected);
+r.close();