From 7ad588e7930f5aeca0e7dafe1d919a1decb09bdc 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
---
 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 d0077df63c5980..06dbaacf9eb7b6 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 00000000000000..1685a35a1f9304
--- /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 00000000000000..8ab686eafeb1f4
--- /dev/null
+++ b/test/message/console_low_stack_space.out
@@ -0,0 +1 @@
+Hello, World!