Silence byte compile errors when installation succeed.

Fixes #1873.

AUTHORS.txt

@@ -14,6 +14,7 @@ Ashley Manton <ajd.manton@googlemail.com>
 Baptiste Mispelon <bmispelon@gmail.com>
 Ben Darnell <ben@bendarnell.com>
 Ben Rosser <rosser.bjr@gmail.com>
+Berker Peksag <berker.peksag@gmail.com>
 Bernardo B. Marques <bernardo.fire@gmail.com>
 Bradley Ayers <bradley.ayers@gmail.com>
 Brian Rosner <brosner@gmail.com>

CHANGES.txt

@@ -1,5 +1,7 @@
 **1.6.0.dev1 (unreleased)**
 
+* Fixed :issue:`1873`. Silence byte compile errors when installation succeed.
+
 * **BACKWARD INCOMPATIBLE** Dropped support for Python 3.1.
 
 * **BACKWARD INCOMPATIBLE** Removed the bundle support which was deprecated in

pip/util.py

@@ -1,3 +1,4 @@
+import contextlib
 import locale
 import re
 import os
@@ -28,7 +29,8 @@ __all__ = ['rmtree', 'display_path', 'backup_dir',
            'split_leading_dir', 'has_leading_dir',
            'make_path_relative', 'normalize_path',
            'renames', 'get_terminal_size', 'get_prog',
-           'unzip_file', 'untar_file', 'unpack_file', 'call_subprocess']
+           'unzip_file', 'untar_file', 'unpack_file', 'call_subprocess',
+           'captured_stdout']
 
 
 def get_prog():
@@ -780,3 +782,31 @@ class FakeFile(object):
 
     def __iter__(self):
         return self._gen
+
+
+@contextlib.contextmanager
+def captured_output(stream_name):
+    """Return a context manager used by captured_stdout/stdin/stderr
+    that temporarily replaces the sys stream *stream_name* with a StringIO.
+
+    Taken from Lib/support/__init__.py in the CPython repo.
+    """
+    from pip._vendor.six.moves import cStringIO
+    orig_stdout = getattr(sys, stream_name)
+    setattr(sys, stream_name, cStringIO())
+    try:
+        yield getattr(sys, stream_name)
+    finally:
+        setattr(sys, stream_name, orig_stdout)
+
+
+def captured_stdout():
+    """Capture the output of sys.stdout:
+
+       with captured_stdout() as stdout:
+           print('hello')
+       self.assertEqual(stdout.getvalue(), 'hello\n')
+
+    Taken from Lib/support/__init__.py in the CPython repo.
+    """
+    return captured_output('stdout')

pip/wheel.py

@@ -20,7 +20,8 @@ from pip.exceptions import InvalidWheelFilename, UnsupportedWheel
 from pip.locations import distutils_scheme
 from pip.log import logger
 from pip import pep425tags
-from pip.util import call_subprocess, normalize_path, make_path_relative
+from pip.util import (call_subprocess, normalize_path, make_path_relative,
+                      captured_stdout)
 from pip._vendor.distlib.scripts import ScriptMaker
 from pip._vendor import pkg_resources
 from pip._vendor.six.moves import configparser
@@ -153,7 +154,11 @@ def move_wheel_files(name, req, wheeldir, user=False, home=None, root=None,
 
     # Compile all of the pyc files that we're going to be installing
     if pycompile:
-        compileall.compile_dir(source, force=True, quiet=True)
+        with captured_stdout() as stdout:
+            compileall.compile_dir(source, force=True, quiet=True)
+        lines = [line for line in stdout.getvalue().splitlines()
+                 if not line.startswith(('SyntaxError:', 'SyntaxWarning:'))]
+        print('\n'.join(lines))
 
     def normpath(src, p):
         return make_path_relative(src, p).replace(os.path.sep, '/')

tests/data/src/compilewheel/setup.cfg

@@ -0,0 +1,5 @@
+[bdist_wheel]
+# This flag says that the code is written to work on both Python 2 and Python
+# 3. If at all possible, it is good practice to do this. If you cannot, you
+# will need to generate wheels for each Python version that you support.
+universal=1

tests/data/src/compilewheel/setup.py

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+from setuptools import setup, find_packages
+
+setup(name='compilewheel',
+      version='1.0',
+      packages=find_packages()
+      )

tests/data/src/compilewheel/simple/__init__.py

@@ -0,0 +1,2 @@
+def spam(gen):
+    yield from gen

tests/functional/test_install_wheel.py

@@ -314,3 +314,9 @@ def test_install_from_wheel_uninstalls_old_version(script, data):
     assert dist_info_folder in result.files_created
     dist_info_folder = script.site_packages / 'simplewheel-1.0.dist-info'
     assert dist_info_folder not in result.files_created
+
+
+def test_wheel_compile_syntax_error(script, data):
+    package = data.packages.join("compilewheel-1.0-py2.py3-none-any.whl")
+    result = script.pip('install', '--compile', package, '--no-index')
+    assert 'SyntaxError: ' not in result.stdout