diff --git a/Lib/packaging/command/build_py.py b/Lib/packaging/command/build_py.py
index 0248213..5faae39 100644
--- a/Lib/packaging/command/build_py.py
+++ b/Lib/packaging/command/build_py.py
@@ -2,7 +2,6 @@
 
 import os
 import imp
-import sys
 from glob import glob
 
 from packaging import logger
@@ -14,10 +13,14 @@
 # marking public APIs
 __all__ = ['build_py']
 
+
 class build_py(Command, Mixin2to3):
 
     description = "build pure Python modules (copy to build directory)"
 
+    # The options for controlling byte compilations are two independent sets;
+    # more info in install_lib or the reST docs
+
     user_options = [
         ('build-lib=', 'd', "directory to build (copy) to"),
         ('compile', 'c', "compile .py to .pyc"),
@@ -35,7 +38,8 @@
         ]
 
     boolean_options = ['compile', 'force']
-    negative_opt = {'no-compile' : 'compile'}
+
+    negative_opt = {'no-compile': 'compile'}
 
     def initialize_options(self):
         self.build_lib = None
@@ -116,7 +120,7 @@
     def get_data_files(self):
         """Generate list of '(package,src_dir,build_dir,filenames)' tuples.
 
-        Helper function for `finalize_options()`.
+        Helper function for finalize_options.
         """
         data = []
         if not self.packages:
@@ -131,7 +135,7 @@
             # Length of path to strip from found files
             plen = 0
             if src_dir:
-                plen = len(src_dir)+1
+                plen = len(src_dir) + 1
 
             # Strip directory from globbed filenames
             filenames = [
@@ -143,7 +147,7 @@
     def find_data_files(self, package, src_dir):
         """Return filenames for package's data files in 'src_dir'.
 
-        Helper function for `get_data_files()`.
+        Helper function for get_data_files.
         """
         globs = (self.package_data.get('', [])
                  + self.package_data.get(package, []))
@@ -158,7 +162,7 @@
     def build_package_data(self):
         """Copy data files into build directory.
 
-        Helper function for `run()`.
+        Helper function for run.
         """
         # FIXME add tests for this method
         for package, src_dir, build_dir, filenames in self.data_files:
@@ -168,16 +172,17 @@
                 self.mkpath(os.path.dirname(target))
                 outf, copied = self.copy_file(srcfile,
                                target, preserve_mode=False)
-                if copied and srcfile in self.distribution.convert_2to3.doctests:
+                doctests = self.distribution.convert_2to3_doctests
+                if copied and srcfile in doctests:
                     self._doctests_2to3.append(outf)
 
     # XXX - this should be moved to the Distribution class as it is not
     # only needed for build_py. It also has no dependencies on this class.
     def get_package_dir(self, package):
         """Return the directory, relative to the top of the source
-           distribution, where package 'package' should be found
-           (at least according to the 'package_dir' option, if any)."""
-
+        distribution, where package 'package' should be found
+        (at least according to the 'package_dir' option, if any).
+        """
         path = package.split('.')
         if self.package_dir is not None:
             path.insert(0, self.package_dir)
@@ -188,8 +193,7 @@
         return ''
 
     def check_package(self, package, package_dir):
-        """Helper function for `find_package_modules()` and `find_modules()'.
-        """
+        """Helper function for find_package_modules and find_modules."""
         # Empty dir name means current directory, which we can probably
         # assume exists.  Also, os.path.exists and isdir don't know about
         # my "empty string means current dir" convention, so we have to
@@ -209,8 +213,8 @@
             if os.path.isfile(init_py):
                 return init_py
             else:
-                logger.warning(("package init file '%s' not found " +
-                                "(or not a regular file)"), init_py)
+                logger.warning("package init file %r not found "
+                               "(or not a regular file)", init_py)
 
         # Either not in a package at all (__init__.py not expected), or
         # __init__.py doesn't exist -- so don't return the filename.
@@ -218,7 +222,7 @@
 
     def check_module(self, module, module_file):
         if not os.path.isfile(module_file):
-            logger.warning("file %s (for module %s) not found",
+            logger.warning("file %r (for module %r) not found",
                            module_file, module)
             return False
         else:
@@ -239,7 +243,7 @@
                 module = os.path.splitext(os.path.basename(f))[0]
                 modules.append((package, module, f))
             else:
-                logger.debug("excluding %s", setup_script)
+                logger.debug("excluding %r", setup_script)
         return modules
 
     def find_modules(self):
@@ -331,7 +335,8 @@
             outputs.append(filename)
             if include_bytecode:
                 if self.compile:
-                    outputs.append(imp.cache_from_source(filename))
+                    outputs.append(imp.cache_from_source(filename,
+                                                         debug_override=True))
                 if self.optimize > 0:
                     outputs.append(imp.cache_from_source(filename,
                                                          debug_override=False))
@@ -361,7 +366,6 @@
     def build_modules(self):
         modules = self.find_modules()
         for package, module, module_file in modules:
-
             # Now "build" the module -- ie. copy the source file to
             # self.build_lib (the build directory for Python source).
             # (Actually, it gets copied to the directory for this package
@@ -370,7 +374,6 @@
 
     def build_packages(self):
         for package in self.packages:
-
             # Get list of (package, module, module_file) tuples based on
             # scanning the package directory.  'package' is only included
             # in the tuple so that 'find_modules()' and
@@ -390,11 +393,6 @@
                 self.build_module(module, module_file, package)
 
     def byte_compile(self, files):
-        if sys.dont_write_bytecode:
-            logger.warning('%s: byte-compiling is disabled, skipping.',
-                           self.get_command_name())
-            return
-
         from packaging.util import byte_compile  # FIXME use compileall
         prefix = self.build_lib
         if prefix[-1] != os.sep:
@@ -403,7 +401,6 @@
         # XXX this code is essentially the same as the 'byte_compile()
         # method of the "install_lib" command, except for the determination
         # of the 'prefix' string.  Hmmm.
-
         if self.compile:
             byte_compile(files, optimize=0,
                          force=self.force, prefix=prefix, dry_run=self.dry_run)
diff --git a/Lib/packaging/command/install_lib.py b/Lib/packaging/command/install_lib.py
index 558966d..f6c785f 100644
--- a/Lib/packaging/command/install_lib.py
+++ b/Lib/packaging/command/install_lib.py
@@ -2,7 +2,6 @@
 
 import os
 import imp
-import sys
 import logging
 
 from packaging import logger
@@ -11,25 +10,18 @@
 
 
 # Extension for Python source files.
+# XXX dead code?  most of the codebase checks for literal '.py'
 if hasattr(os, 'extsep'):
     PYTHON_SOURCE_EXTENSION = os.extsep + "py"
 else:
     PYTHON_SOURCE_EXTENSION = ".py"
 
+
 class install_lib(Command):
 
     description = "install all modules (extensions and pure Python)"
 
-    # The byte-compilation options are a tad confusing.  Here are the
-    # possible scenarios:
-    #   1) no compilation at all (--no-compile --no-optimize)
-    #   2) compile .pyc only (--compile --no-optimize; default)
-    #   3) compile .pyc and "level 1" .pyo (--compile --optimize)
-    #   4) compile "level 1" .pyo only (--no-compile --optimize)
-    #   5) compile .pyc and "level 2" .pyo (--compile --optimize-more)
-    #   6) compile "level 2" .pyo only (--no-compile --optimize-more)
-    #
-    # The UI for this is two option, 'compile' and 'optimize'.
+    # The options for controlling byte compilations are two independent sets:
     # 'compile' is strictly boolean, and only decides whether to
     # generate .pyc files.  'optimize' is three-way (0, 1, or 2), and
     # decides both whether to generate .pyo files and what level of
@@ -37,7 +29,7 @@
 
     user_options = [
         ('install-dir=', 'd', "directory to install to"),
-        ('build-dir=','b', "build directory (where to install from)"),
+        ('build-dir=', 'b', "build directory (where to install from)"),
         ('force', 'f', "force installation (overwrite existing files)"),
         ('compile', 'c', "compile .py to .pyc [default]"),
         ('no-compile', None, "don't compile .py files"),
@@ -48,7 +40,8 @@
         ]
 
     boolean_options = ['force', 'compile', 'skip-build']
-    negative_opt = {'no-compile' : 'compile'}
+
+    negative_opt = {'no-compile': 'compile'}
 
     def initialize_options(self):
         # let the 'install_dist' command dictate our installation directory
@@ -66,7 +59,8 @@
         self.set_undefined_options('install_dist',
                                    ('build_lib', 'build_dir'),
                                    ('install_lib', 'install_dir'),
-                                   'force', 'compile', 'optimize', 'skip_build')
+                                   'force', 'compile', 'optimize',
+                                   'skip_build')
 
         if self.compile is None:
             self.compile = True
@@ -115,14 +109,6 @@
         return outfiles
 
     def byte_compile(self, files):
-        if sys.dont_write_bytecode:
-            # XXX do we want this?  because a Python runs without bytecode
-            # doesn't mean that the *dists should not contain bytecode
-            #--or does it?
-            logger.warning('%s: byte-compiling is disabled, skipping.',
-                           self.get_command_name())
-            return
-
         from packaging.util import byte_compile  # FIXME use compileall
 
         # Get the "--root" directory supplied to the "install_dist" command,
@@ -138,13 +124,11 @@
         if self.compile:
             byte_compile(files, optimize=0,
                          force=self.force, prefix=install_root,
-                         dry_run=self.dry_run)
+                         verbose=verbose, dry_run=self.dry_run)
         if self.optimize > 0:
             byte_compile(files, optimize=self.optimize,
                          force=self.force, prefix=install_root,
-                         verbose=verbose,
-                         dry_run=self.dry_run)
-
+                         verbose=verbose, dry_run=self.dry_run)
 
     # -- Utility methods -----------------------------------------------
 
@@ -173,14 +157,14 @@
             if ext != PYTHON_SOURCE_EXTENSION:
                 continue
             if self.compile:
-                bytecode_files.append(imp.cache_from_source(py_file))
+                bytecode_files.append(imp.cache_from_source(
+                    py_file, debug_override=True))
             if self.optimize > 0:
                 bytecode_files.append(imp.cache_from_source(
                     py_file, debug_override=False))
 
         return bytecode_files
 
-
     # -- External interface --------------------------------------------
     # (called by outsiders)
 
diff --git a/Lib/packaging/errors.py b/Lib/packaging/errors.py
index 8924a2d..8878129 100644
--- a/Lib/packaging/errors.py
+++ b/Lib/packaging/errors.py
@@ -72,10 +72,6 @@
     """Syntax error in a file list template."""
 
 
-class PackagingByteCompileError(PackagingError):
-    """Byte compile error."""
-
-
 class PackagingPyPIError(PackagingError):
     """Any problem occuring during using the indexes."""
 
diff --git a/Lib/packaging/tests/support.py b/Lib/packaging/tests/support.py
index 6e26ea4..66890c9 100644
--- a/Lib/packaging/tests/support.py
+++ b/Lib/packaging/tests/support.py
@@ -53,7 +53,7 @@
     # misc. functions and decorators
     'fake_dec', 'create_distribution', 'copy_xxmodule_c', 'fixup_build_ext',
     # imported from this module for backport purposes
-    'unittest', 'requires_zlib', 'skip_unless_symlink',
+    'unittest', 'requires_zlib', 'skip_2to3_optimize', 'skip_unless_symlink',
 ]
 
 
@@ -357,3 +357,7 @@
 except ImportError:
     skip_unless_symlink = unittest.skip(
         'requires test.support.skip_unless_symlink')
+
+
+skip_2to3_optimize = unittest.skipIf(sys.flags.optimize,
+                                     "2to3 doesn't work under -O")
diff --git a/Lib/packaging/tests/test_command_build_py.py b/Lib/packaging/tests/test_command_build_py.py
index 9d519e3..4d93faa 100644
--- a/Lib/packaging/tests/test_command_build_py.py
+++ b/Lib/packaging/tests/test_command_build_py.py
@@ -62,12 +62,8 @@
         pycache_dir = os.path.join(pkgdest, "__pycache__")
         self.assertIn("__init__.py", files)
         self.assertIn("README.txt", files)
-        if sys.dont_write_bytecode:
-            self.assertFalse(os.path.exists(pycache_dir))
-        else:
-            # XXX even with -O, packaging writes pyc, not pyo; bug?
-            pyc_files = os.listdir(pycache_dir)
-            self.assertIn("__init__.%s.pyc" % imp.get_tag(), pyc_files)
+        pyc_files = os.listdir(pycache_dir)
+        self.assertIn("__init__.%s.pyc" % imp.get_tag(), pyc_files)
 
     def test_empty_package_dir(self):
         # See SF 1668596/1720897.
@@ -102,7 +98,6 @@
             os.chdir(cwd)
             sys.stdout = old_stdout
 
-    @unittest.skipIf(sys.dont_write_bytecode, 'byte-compile disabled')
     def test_byte_compile(self):
         project_dir, dist = self.create_dist(py_modules=['boiledeggs'])
         os.chdir(project_dir)
@@ -118,7 +113,6 @@
         found = os.listdir(os.path.join(cmd.build_lib, '__pycache__'))
         self.assertEqual(found, ['boiledeggs.%s.pyc' % imp.get_tag()])
 
-    @unittest.skipIf(sys.dont_write_bytecode, 'byte-compile disabled')
     def test_byte_compile_optimized(self):
         project_dir, dist = self.create_dist(py_modules=['boiledeggs'])
         os.chdir(project_dir)
@@ -136,21 +130,13 @@
         self.assertEqual(sorted(found), ['boiledeggs.%s.pyc' % imp.get_tag(),
                                          'boiledeggs.%s.pyo' % imp.get_tag()])
 
-    def test_dont_write_bytecode(self):
-        # makes sure byte_compile is not used
-        pkg_dir, dist = self.create_dist()
-        cmd = build_py(dist)
-        cmd.compile = True
-        cmd.optimize = 1
-
-        old_dont_write_bytecode = sys.dont_write_bytecode
+    def test_byte_compile_under_B(self):
+        # make sure byte compilation works under -B (dont_write_bytecode)
+        self.addCleanup(setattr, sys, 'dont_write_bytecode',
+                        sys.dont_write_bytecode)
         sys.dont_write_bytecode = True
-        try:
-            cmd.byte_compile([])
-        finally:
-            sys.dont_write_bytecode = old_dont_write_bytecode
-
-        self.assertIn('byte-compiling is disabled', self.get_logs()[0])
+        self.test_byte_compile()
+        self.test_byte_compile_optimized()
 
 
 def test_suite():
diff --git a/Lib/packaging/tests/test_command_install_lib.py b/Lib/packaging/tests/test_command_install_lib.py
index 3f36822..e58e812 100644
--- a/Lib/packaging/tests/test_command_install_lib.py
+++ b/Lib/packaging/tests/test_command_install_lib.py
@@ -17,7 +17,7 @@
     restore_environ = ['PYTHONPATH']
 
     def test_finalize_options(self):
-        pkg_dir, dist = self.create_dist()
+        dist = self.create_dist()[1]
         cmd = install_lib(dist)
 
         cmd.finalize_options()
@@ -34,71 +34,73 @@
         cmd.finalize_options()
         self.assertEqual(cmd.optimize, 2)
 
-    @unittest.skipIf(sys.dont_write_bytecode, 'byte-compile disabled')
     def test_byte_compile(self):
-        pkg_dir, dist = self.create_dist()
-        os.chdir(pkg_dir)
+        project_dir, dist = self.create_dist()
+        os.chdir(project_dir)
         cmd = install_lib(dist)
         cmd.compile = True
         cmd.optimize = 1
 
-        f = os.path.join(pkg_dir, 'foo.py')
+        f = os.path.join(project_dir, 'foo.py')
         self.write_file(f, '# python file')
         cmd.byte_compile([f])
-        pyc_file = imp.cache_from_source('foo.py')
+        pyc_file = imp.cache_from_source('foo.py', debug_override=True)
         pyo_file = imp.cache_from_source('foo.py', debug_override=False)
         self.assertTrue(os.path.exists(pyc_file))
         self.assertTrue(os.path.exists(pyo_file))
 
-    def test_get_outputs(self):
-        pkg_dir, dist = self.create_dist()
-        cmd = install_lib(dist)
-
-        # setting up a dist environment
-        cmd.compile = True
-        cmd.optimize = 1
-        cmd.install_dir = pkg_dir
-        f = os.path.join(pkg_dir, '__init__.py')
-        self.write_file(f, '# python package')
-        cmd.distribution.ext_modules = [Extension('foo', ['xxx'])]
-        cmd.distribution.packages = [pkg_dir]
-
-        # make sure the build_lib is set the temp dir
-        build_dir = os.path.split(pkg_dir)[0]
-        cmd.get_finalized_command('build_py').build_lib = build_dir
-
-        # get_output should return 4 elements
-        self.assertEqual(len(cmd.get_outputs()), 4)
-
-    def test_get_inputs(self):
-        pkg_dir, dist = self.create_dist()
-        cmd = install_lib(dist)
-
-        # setting up a dist environment
-        cmd.compile = True
-        cmd.optimize = 1
-        cmd.install_dir = pkg_dir
-        f = os.path.join(pkg_dir, '__init__.py')
-        self.write_file(f, '# python package')
-        cmd.distribution.ext_modules = [Extension('foo', ['xxx'])]
-        cmd.distribution.packages = [pkg_dir]
-
-        # get_input should return 2 elements
-        self.assertEqual(len(cmd.get_inputs()), 2)
-
-    def test_dont_write_bytecode(self):
-        # makes sure byte_compile is not used
-        pkg_dir, dist = self.create_dist()
-        cmd = install_lib(dist)
-        cmd.compile = True
-        cmd.optimize = 1
-
+    def test_byte_compile_under_B(self):
+        # make sure byte compilation works under -B (dont_write_bytecode)
         self.addCleanup(setattr, sys, 'dont_write_bytecode',
                         sys.dont_write_bytecode)
         sys.dont_write_bytecode = True
-        cmd.byte_compile([])
+        self.test_byte_compile()
 
-        self.assertIn('byte-compiling is disabled', self.get_logs()[0])
+    def test_get_outputs(self):
+        project_dir, dist = self.create_dist()
+        os.chdir(project_dir)
+        os.mkdir('spam')
+        cmd = install_lib(dist)
+
+        # setting up a dist environment
+        cmd.compile = True
+        cmd.optimize = 1
+        cmd.install_dir = self.mkdtemp()
+        f = os.path.join(project_dir, 'spam', '__init__.py')
+        self.write_file(f, '# python package')
+        cmd.distribution.ext_modules = [Extension('foo', ['xxx'])]
+        cmd.distribution.packages = ['spam']
+
+        # make sure the build_lib is set the temp dir  # XXX what?  this is not
+        # needed in the same distutils test and should work without manual
+        # intervention
+        build_dir = os.path.split(project_dir)[0]
+        cmd.get_finalized_command('build_py').build_lib = build_dir
+
+        # get_outputs should return 4 elements: spam/__init__.py, .pyc and
+        # .pyo, foo.import-tag-abiflags.so / foo.pyd
+        outputs = cmd.get_outputs()
+        self.assertEqual(len(outputs), 4, outputs)
+
+    def test_get_inputs(self):
+        project_dir, dist = self.create_dist()
+        os.chdir(project_dir)
+        os.mkdir('spam')
+        cmd = install_lib(dist)
+
+        # setting up a dist environment
+        cmd.compile = True
+        cmd.optimize = 1
+        cmd.install_dir = self.mkdtemp()
+        f = os.path.join(project_dir, 'spam', '__init__.py')
+        self.write_file(f, '# python package')
+        cmd.distribution.ext_modules = [Extension('foo', ['xxx'])]
+        cmd.distribution.packages = ['spam']
+
+        # get_inputs should return 2 elements: spam/__init__.py and
+        # foo.import-tag-abiflags.so / foo.pyd
+        inputs = cmd.get_inputs()
+        self.assertEqual(len(inputs), 2, inputs)
 
 
 def test_suite():
diff --git a/Lib/packaging/tests/test_mixin2to3.py b/Lib/packaging/tests/test_mixin2to3.py
index 000a992..c439bcb 100644
--- a/Lib/packaging/tests/test_mixin2to3.py
+++ b/Lib/packaging/tests/test_mixin2to3.py
@@ -8,6 +8,7 @@
                         support.LoggingCatcher,
                         unittest.TestCase):
 
+    @support.skip_2to3_optimize
     def test_convert_code_only(self):
         # used to check if code gets converted properly.
         code = "print 'test'"
diff --git a/Lib/packaging/tests/test_util.py b/Lib/packaging/tests/test_util.py
index 1cf5c93..00d61e0 100644
--- a/Lib/packaging/tests/test_util.py
+++ b/Lib/packaging/tests/test_util.py
@@ -10,7 +10,7 @@
 from io import StringIO
 
 from packaging.errors import (
-    PackagingPlatformError, PackagingByteCompileError, PackagingFileError,
+    PackagingPlatformError, PackagingFileError,
     PackagingExecError, InstallationException)
 from packaging import util
 from packaging.dist import Distribution
@@ -138,15 +138,8 @@
             self._uname = None
         os.uname = self._get_uname
 
-        # patching POpen
-        self.old_find_executable = util.find_executable
-        util.find_executable = self._find_executable
-        self._exes = {}
-        self.old_popen = subprocess.Popen
-        self.old_stdout = sys.stdout
-        self.old_stderr = sys.stderr
-        FakePopen.test_class = self
-        subprocess.Popen = FakePopen
+    def _get_uname(self):
+        return self._uname
 
     def tearDown(self):
         # getting back the environment
@@ -161,17 +154,24 @@
             os.uname = self.uname
         else:
             del os.uname
+        super(UtilTestCase, self).tearDown()
+
+    def mock_popen(self):
+        self.old_find_executable = util.find_executable
+        util.find_executable = self._find_executable
+        self._exes = {}
+        self.old_popen = subprocess.Popen
+        self.old_stdout = sys.stdout
+        self.old_stderr = sys.stderr
+        FakePopen.test_class = self
+        subprocess.Popen = FakePopen
+        self.addCleanup(self.unmock_popen)
+
+    def unmock_popen(self):
         util.find_executable = self.old_find_executable
         subprocess.Popen = self.old_popen
         sys.old_stdout = self.old_stdout
         sys.old_stderr = self.old_stderr
-        super(UtilTestCase, self).tearDown()
-
-    def _set_uname(self, uname):
-        self._uname = uname
-
-    def _get_uname(self):
-        return self._uname
 
     def test_convert_path(self):
         # linux/mac
@@ -283,6 +283,7 @@
         return None
 
     def test_get_compiler_versions(self):
+        self.mock_popen()
         # get_versions calls distutils.spawn.find_executable on
         # 'gcc', 'ld' and 'dllwrap'
         self.assertEqual(get_compiler_versions(), (None, None, None))
@@ -323,15 +324,12 @@
         res = get_compiler_versions()
         self.assertEqual(res[2], None)
 
-    def test_dont_write_bytecode(self):
-        # makes sure byte_compile raise a PackagingError
-        # if sys.dont_write_bytecode is True
-        old_dont_write_bytecode = sys.dont_write_bytecode
+    def test_byte_compile_under_B(self):
+        # make sure byte compilation works under -B (dont_write_bytecode)
+        self.addCleanup(setattr, sys, 'dont_write_bytecode',
+                        sys.dont_write_bytecode)
         sys.dont_write_bytecode = True
-        try:
-            self.assertRaises(PackagingByteCompileError, byte_compile, [])
-        finally:
-            sys.dont_write_bytecode = old_dont_write_bytecode
+        byte_compile([])
 
     def test_newer(self):
         self.assertRaises(PackagingFileError, util.newer, 'xxx', 'xxx')
@@ -418,6 +416,7 @@
         self.assertRaises(ImportError, resolve_name, 'a.b.Spam')
         self.assertRaises(ImportError, resolve_name, 'a.b.c.Spam')
 
+    @support.skip_2to3_optimize
     def test_run_2to3_on_code(self):
         content = "print 'test'"
         converted_content = "print('test')"
@@ -431,6 +430,7 @@
         file_handle.close()
         self.assertEqual(new_content, converted_content)
 
+    @support.skip_2to3_optimize
     def test_run_2to3_on_doctests(self):
         # to check if text files containing doctests only get converted.
         content = ">>> print 'test'\ntest\n"
@@ -448,8 +448,6 @@
     @unittest.skipUnless(os.name in ('nt', 'posix'),
                          'runs only under posix or nt')
     def test_spawn(self):
-        # no patching of Popen here
-        subprocess.Popen = self.old_popen
         tmpdir = self.mkdtemp()
 
         # creating something executable
@@ -545,8 +543,6 @@
         self.assertEqual(args['py_modules'], dist.py_modules)
 
     def test_generate_setup_py(self):
-        # undo subprocess.Popen monkey-patching before using assert_python_*
-        subprocess.Popen = self.old_popen
         os.chdir(self.mkdtemp())
         self.write_file('setup.cfg', textwrap.dedent("""\
             [metadata]
diff --git a/Lib/packaging/util.py b/Lib/packaging/util.py
index 8dd715f..e76e3c3 100644
--- a/Lib/packaging/util.py
+++ b/Lib/packaging/util.py
@@ -20,8 +20,8 @@
 
 from packaging import logger
 from packaging.errors import (PackagingPlatformError, PackagingFileError,
-                              PackagingByteCompileError, PackagingExecError,
-                              InstallationException, PackagingInternalError)
+                              PackagingExecError, InstallationException,
+                              PackagingInternalError)
 
 __all__ = [
     # file dependencies
@@ -325,12 +325,10 @@
     the source for details).  The 'direct' flag is used by the script
     generated in indirect mode; unless you know what you're doing, leave
     it set to None.
-    """
-    # nothing is done if sys.dont_write_bytecode is True
-    # FIXME this should not raise an error
-    if sys.dont_write_bytecode:
-        raise PackagingByteCompileError('byte-compiling is disabled.')
 
+    This function is independent from the running Python's -O or -B options;
+    it is fully controlled by the parameters passed in.
+    """
     # First, if the caller didn't force us into direct or indirect mode,
     # figure out which mode we should be in.  We take a conservative
     # approach: choose direct mode *only* if the current interpreter is
@@ -417,12 +415,10 @@
             # Terminology from the py_compile module:
             #   cfile - byte-compiled file
             #   dfile - purported source filename (same as 'file' by default)
-            if optimize >= 0:
-                cfile = imp.cache_from_source(file,
-                                              debug_override=not optimize)
-            else:
-                cfile = imp.cache_from_source(file)
+            debug_override = not optimize
+            cfile = imp.cache_from_source(file, debug_override)
             dfile = file
+
             if prefix:
                 if file[:len(prefix)] != prefix:
                     raise ValueError("invalid prefix: filename %r doesn't "