From 8a6dcd040f35b023f0cc0208c4bc553fcc7e6a4d Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Tue, 26 Mar 2019 16:28:53 +0100
Subject: [PATCH] module: fix repl require calling the same file again

This makes sure multiple require calls will not fail in case a file
was created after the first attempt.

PR-URL: https://github.com/nodejs/node/pull/26928
Fixes: https://github.com/nodejs/node/issues/26926
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>
---
 lib/internal/modules/cjs/loader.js            | 16 ++++++------
 .../parallel/test-repl-require-after-write.js | 25 +++++++++++++++++++
 2 files changed, 34 insertions(+), 7 deletions(-)
 create mode 100644 test/parallel/test-repl-require-after-write.js

diff --git a/lib/internal/modules/cjs/loader.js b/lib/internal/modules/cjs/loader.js
index 2f06d355460125..e03cece3adb792 100644
--- a/lib/internal/modules/cjs/loader.js
+++ b/lib/internal/modules/cjs/loader.js
@@ -78,14 +78,15 @@ const {
 const isWindows = process.platform === 'win32';
 
 let requireDepth = 0;
-let statCache = new Map();
+let statCache = null;
 function stat(filename) {
   filename = path.toNamespacedPath(filename);
-  if (statCache === null) statCache = new Map();
-  let result = statCache.get(filename);
-  if (result !== undefined) return result;
-  result = internalModuleStat(filename);
-  statCache.set(filename, result);
+  if (statCache !== null) {
+    const result = statCache.get(filename);
+    if (result !== undefined) return result;
+  }
+  const result = internalModuleStat(filename);
+  if (statCache !== null) statCache.set(filename, result);
   return result;
 }
 
@@ -188,7 +189,7 @@ Module._debug = deprecate(debug, 'Module._debug is deprecated.', 'DEP0077');
 //   -> a.<ext>
 //   -> a/index.<ext>
 
-// check if the directory is a package.json dir
+// Check if the directory is a package.json dir.
 const packageMainCache = Object.create(null);
 
 function readPackage(requestPath) {
@@ -794,6 +795,7 @@ Module.prototype._compile = function(content, filename) {
   const exports = this.exports;
   const thisValue = exports;
   const module = this;
+  if (requireDepth === 0) statCache = new Map();
   if (inspectorWrapper) {
     result = inspectorWrapper(compiledWrapper, thisValue, exports,
                               require, module, filename, dirname);
diff --git a/test/parallel/test-repl-require-after-write.js b/test/parallel/test-repl-require-after-write.js
new file mode 100644
index 00000000000000..e4d9b2f5a024dc
--- /dev/null
+++ b/test/parallel/test-repl-require-after-write.js
@@ -0,0 +1,25 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+const spawn = require('child_process').spawn;
+// Use -i to force node into interactive mode, despite stdout not being a TTY
+const child = spawn(process.execPath, ['-i']);
+
+let out = '';
+const input = "try { require('./non-existent.json'); } catch {} " +
+              "require('fs').writeFileSync('./non-existent.json', '1');" +
+              "require('./non-existent.json');";
+
+child.stderr.on('data', common.mustNotCall());
+
+child.stdout.setEncoding('utf8');
+child.stdout.on('data', (c) => {
+  out += c;
+});
+child.stdout.on('end', common.mustCall(() => {
+  assert.strictEqual(out, '> 1\n> ');
+}));
+
+child.stdin.end(input);