From 15376835372fd7116f87a79103e7acc26672f395 Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh+mozilla@glandium.org>
Date: Fri, 15 Apr 2016 10:41:52 +0900
Subject: [PATCH] Bug 1264831 - Work around issues with the exec statement in
 older python 2.7 versions. r=gps

---
 python/mozbuild/mozbuild/configure/__init__.py |  9 ++++-----
 python/mozbuild/mozbuild/frontend/sandbox.py   | 11 +++++------
 python/mozbuild/mozbuild/util.py               | 18 +++++++++++++++++-
 3 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/python/mozbuild/mozbuild/configure/__init__.py b/python/mozbuild/mozbuild/configure/__init__.py
index c1362079130d..c81a8d632423 100644
--- a/python/mozbuild/mozbuild/configure/__init__.py
+++ b/python/mozbuild/mozbuild/configure/__init__.py
@@ -28,10 +28,12 @@ from mozbuild.configure.util import (
     LineIO,
 )
 from mozbuild.util import (
+    exec_,
     memoize,
     ReadOnlyDict,
     ReadOnlyNamespace,
 )
+
 import mozpack.path as mozpath
 
 
@@ -200,7 +202,7 @@ class ConfigureSandbox(dict):
 
         code = compile(source, path, 'exec')
 
-        exec(code, self)
+        exec_(code, self)
 
         self._paths.pop(-1)
 
@@ -570,10 +572,7 @@ class ConfigureSandbox(dict):
             import_line += 'import %s' % _import
             if _as:
                 import_line += ' as %s' % _as
-            # Some versions of python fail with "SyntaxError: unqualified exec
-            # is not allowed in function '_apply_imports' it contains a nested
-            # function with free variable" when using the exec function.
-            exec import_line in {}, glob
+            exec_(import_line, {}, glob)
 
     def _resolve_and_set(self, data, name, value):
         # Don't set anything when --help was on the command line
diff --git a/python/mozbuild/mozbuild/frontend/sandbox.py b/python/mozbuild/mozbuild/frontend/sandbox.py
index 9f2666f8c51b..0bf1599f2084 100644
--- a/python/mozbuild/mozbuild/frontend/sandbox.py
+++ b/python/mozbuild/mozbuild/frontend/sandbox.py
@@ -23,7 +23,10 @@ import os
 import sys
 import weakref
 
-from mozbuild.util import ReadOnlyDict
+from mozbuild.util import (
+    exec_,
+    ReadOnlyDict,
+)
 from .context import Context
 from mozpack.files import FileFinder
 
@@ -174,11 +177,7 @@ class Sandbox(dict):
             old_source = self._current_source
             self._current_source = source
             try:
-                # Ideally, we'd use exec(code, self), but that yield the
-                # following error:
-                # SyntaxError: unqualified exec is not allowed in function
-                # 'execute' it is a nested function.
-                exec code in self
+                exec_(code, self)
             finally:
                 self._current_source = old_source
 
diff --git a/python/mozbuild/mozbuild/util.py b/python/mozbuild/mozbuild/util.py
index a1b70268334c..e7caee0adaa2 100644
--- a/python/mozbuild/mozbuild/util.py
+++ b/python/mozbuild/mozbuild/util.py
@@ -5,7 +5,7 @@
 # This file contains miscellaneous utility functions that don't belong anywhere
 # in particular.
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, unicode_literals, print_function
 
 import argparse
 import collections
@@ -42,6 +42,22 @@ if sys.platform == 'win32':
     _FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x2000
 
 
+def exec_(object, globals=None, locals=None):
+    """Wrapper around the exec statement to avoid bogus errors like:
+
+    SyntaxError: unqualified exec is not allowed in function ...
+    it is a nested function.
+
+    or
+
+    SyntaxError: unqualified exec is not allowed in function ...
+    it contains a nested function with free variable
+
+    which happen with older versions of python 2.7.
+    """
+    exec(object, globals, locals)
+
+
 def hash_file(path, hasher=None):
     """Hashes a file specified by the path given and returns the hex digest."""