From 178f3080f81534fae4c2bc60e0596c8f739e88f2 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Fri, 20 May 2016 23:11:27 +0200
Subject: [PATCH] module: don't cache uninitialized builtins

Don't cache the exported values of fully uninitialized builtins.
This works by adding an additional `loading` flag that is only
active during initial loading of an internal module and checking
that either the module is fully loaded or is in that state before
using its cached value.

This has the effect that builtins modules which could not be loaded
(e.g. because compilation failed due to missing stack space) can be
loaded at a later point.

Fixes: https://github.com/nodejs/node/issues/6899
PR-URL: https://github.com/nodejs/node/pull/6907
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
---
 lib/internal/bootstrap_node.js           | 23 +++++++++++++++--------
 test/message/console_low_stack_space.js  | 22 ++++++++++++++++++++++
 test/message/console_low_stack_space.out |  1 +
 3 files changed, 38 insertions(+), 8 deletions(-)
 create mode 100644 test/message/console_low_stack_space.js
 create mode 100644 test/message/console_low_stack_space.out

diff --git a/lib/internal/bootstrap_node.js b/lib/internal/bootstrap_node.js
index d0077df63c..06dbaacf9e 100644
--- a/lib/internal/bootstrap_node.js
+++ b/lib/internal/bootstrap_node.js
@@ -357,6 +357,7 @@
     this.id = id;
     this.exports = {};
     this.loaded = false;
+    this.loading = false;
   }
 
   NativeModule._source = process.binding('natives');
@@ -368,7 +369,7 @@
     }
 
     var cached = NativeModule.getCached(id);
-    if (cached) {
+    if (cached && (cached.loaded || cached.loading)) {
       return cached.exports;
     }
 
@@ -432,14 +433,20 @@
     var source = NativeModule.getSource(this.id);
     source = NativeModule.wrap(source);
 
-    var fn = runInThisContext(source, {
-      filename: this.filename,
-      lineOffset: 0,
-      displayErrors: true
-    });
-    fn(this.exports, NativeModule.require, this, this.filename);
+    this.loading = true;
+
+    try {
+      var fn = runInThisContext(source, {
+        filename: this.filename,
+        lineOffset: 0,
+        displayErrors: true
+      });
+      fn(this.exports, NativeModule.require, this, this.filename);
 
-    this.loaded = true;
+      this.loaded = true;
+    } finally {
+      this.loading = false;
+    }
   };
 
   NativeModule.prototype.cache = function() {
diff --git a/test/message/console_low_stack_space.js b/test/message/console_low_stack_space.js
new file mode 100644
index 0000000000..1685a35a1f
--- /dev/null
+++ b/test/message/console_low_stack_space.js
@@ -0,0 +1,22 @@
+'use strict';
+// copy console accessor because requiring ../common touches it
+const consoleDescriptor = Object.getOwnPropertyDescriptor(global, 'console');
+delete global.console;
+global.console = {};
+
+require('../common');
+
+function a() {
+  try {
+    return a();
+  } catch (e) {
+    const console = consoleDescriptor.get();
+    if (console.log) {
+      console.log('Hello, World!');
+    } else {
+      throw e;
+    }
+  }
+}
+
+a();
diff --git a/test/message/console_low_stack_space.out b/test/message/console_low_stack_space.out
new file mode 100644
index 0000000000..8ab686eafe
--- /dev/null
+++ b/test/message/console_low_stack_space.out
@@ -0,0 +1 @@
+Hello, World!