From 4d4fc58fce93a07a210e98e42c439985486e43c0 Mon Sep 17 00:00:00 2001
From: Pavel Minaev <int19h@gmail.com>
Date: Wed, 21 Feb 2018 13:18:08 -0800
Subject: [PATCH] Remove sys.path entry for vendored pydevd after loading it.

Improve error reporting when pydevd is imported before ptvsd.
---
 ptvsd/__init__.py | 28 +++++++++++++++++++++++++---
 ptvsd/wrapper.py  |  3 +--
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/ptvsd/__init__.py b/ptvsd/__init__.py
index 922fbe7c..9907ffec 100644
--- a/ptvsd/__init__.py
+++ b/ptvsd/__init__.py
@@ -5,10 +5,32 @@
 __author__ = "Microsoft Corporation <ptvshelp@microsoft.com>"
 __version__ = "4.0.0a1"
 
-# ptvsd must always be imported before pydevd
 import sys
-assert 'pydevd' not in sys.modules
+import os.path
+
+# ptvsd must always be imported before pydevd
+if 'pydevd' in sys.modules:
+    raise ImportError('ptvsd must be imported before pydevd')
 
 # Add our vendored pydevd directory to path, so that it gets found first.
-import os.path
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'pydevd'))
+
+# Load our wrapper module, which will detour various functionality inside pydevd.
+# This must be done before the imports below, otherwise some modules will end up
+# with local copies of pre-detour functions.
+import ptvsd.wrapper
+
+# Now make sure all the top-level modules and packages in pydevd are loaded.
+import _pydev_bundle
+import _pydev_imps
+import _pydev_runfiles
+import _pydevd_bundle
+import _pydevd_frame_eval
+import pydev_ipython
+import pydevd_concurrency_analyser
+import pydevd_plugins
+import pydevd
+
+# Remove sys.path entry added above - any pydevd modules that aren't loaded at
+# this point, will be loaded using their parent package's __path__.
+del sys.path[0]
diff --git a/ptvsd/wrapper.py b/ptvsd/wrapper.py
index f44a3ceb..c43ab861 100644
--- a/ptvsd/wrapper.py
+++ b/ptvsd/wrapper.py
@@ -2,8 +2,7 @@
 # Licensed under the MIT License. See LICENSE in the project root
 # for license information.
 
-# TODO: with_statement is not needed
-from __future__ import print_function, with_statement, absolute_import
+from __future__ import print_function, absolute_import
 
 import atexit
 import os