Issue #23731: Implement PEP 488.

The concept of .pyo files no longer exists. Now .pyc files have an
optional `opt-` tag which specifies if any extra optimizations beyond
the peepholer were applied.

command/build_py.py

@@ -314,10 +314,10 @@ class build_py (Command):
             if include_bytecode:
                 if self.compile:
                     outputs.append(importlib.util.cache_from_source(
-                        filename, debug_override=True))
+                        filename, optimization=''))
                 if self.optimize > 0:
                     outputs.append(importlib.util.cache_from_source(
-                        filename, debug_override=False))
+                        filename, optimization=self.optimize))
 
         outputs += [
             os.path.join(build_dir, filename)

command/install_lib.py

@@ -22,15 +22,15 @@ class install_lib(Command):
     # 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)
+    #   3) compile .pyc and "opt-1" .pyc (--compile --optimize)
+    #   4) compile "opt-1" .pyc only (--no-compile --optimize)
+    #   5) compile .pyc and "opt-2" .pyc (--compile --optimize-more)
+    #   6) compile "opt-2" .pyc only (--no-compile --optimize-more)
     #
-    # The UI for this is two option, 'compile' and 'optimize'.
+    # The UI for this is two options, 'compile' and 'optimize'.
     # '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
+    # decides both whether to generate .pyc files and what level of
     # optimization to use.
 
     user_options = [
@@ -166,10 +166,10 @@ class install_lib(Command):
                 continue
             if self.compile:
                 bytecode_files.append(importlib.util.cache_from_source(
-                    py_file, debug_override=True))
+                    py_file, optimization=''))
             if self.optimize > 0:
                 bytecode_files.append(importlib.util.cache_from_source(
-                    py_file, debug_override=False))
+                    py_file, optimization=self.optimize))
 
         return bytecode_files
 

tests/test_build_py.py

@@ -120,8 +120,8 @@ class BuildPyTestCase(support.TempdirManager,
         found = os.listdir(cmd.build_lib)
         self.assertEqual(sorted(found), ['__pycache__', 'boiledeggs.py'])
         found = os.listdir(os.path.join(cmd.build_lib, '__pycache__'))
-        self.assertEqual(sorted(found),
-                         ['boiledeggs.%s.pyo' % sys.implementation.cache_tag])
+        expect = 'boiledeggs.{}.opt-1.pyc'.format(sys.implementation.cache_tag)
+        self.assertEqual(sorted(found), [expect])
 
     def test_dir_in_package_data(self):
         """

tests/test_install_lib.py

@@ -44,12 +44,11 @@ class InstallLibTestCase(support.TempdirManager,
         f = os.path.join(project_dir, 'foo.py')
         self.write_file(f, '# python file')
         cmd.byte_compile([f])
-        pyc_file = importlib.util.cache_from_source('foo.py',
-                                                    debug_override=True)
-        pyo_file = importlib.util.cache_from_source('foo.py',
-                                                    debug_override=False)
+        pyc_file = importlib.util.cache_from_source('foo.py', optimization='')
+        pyc_opt_file = importlib.util.cache_from_source('foo.py',
+                                                    optimization=cmd.optimize)
         self.assertTrue(os.path.exists(pyc_file))
-        self.assertTrue(os.path.exists(pyo_file))
+        self.assertTrue(os.path.exists(pyc_opt_file))
 
     def test_get_outputs(self):
         project_dir, dist = self.create_dist()
@@ -66,8 +65,8 @@ class InstallLibTestCase(support.TempdirManager,
         cmd.distribution.packages = ['spam']
         cmd.distribution.script_name = 'setup.py'
 
-        # get_outputs should return 4 elements: spam/__init__.py, .pyc and
-        # .pyo, foo.import-tag-abiflags.so / foo.pyd
+        # get_outputs should return 4 elements: spam/__init__.py and .pyc,
+        # foo.import-tag-abiflags.so / foo.pyd
         outputs = cmd.get_outputs()
         self.assertEqual(len(outputs), 4, outputs)
 

util.py

@@ -322,11 +322,11 @@ def byte_compile (py_files,
                   prefix=None, base_dir=None,
                   verbose=1, dry_run=0,
                   direct=None):
-    """Byte-compile a collection of Python source files to either .pyc
-    or .pyo files in a __pycache__ subdirectory.  'py_files' is a list
+    """Byte-compile a collection of Python source files to .pyc
+    files in a __pycache__ subdirectory.  'py_files' is a list
     of files to compile; any files that don't end in ".py" are silently
     skipped.  'optimize' must be one of the following:
-      0 - don't optimize (generate .pyc)
+      0 - don't optimize
       1 - normal optimization (like "python -O")
       2 - extra optimization (like "python -OO")
     If 'force' is true, all files are recompiled regardless of
@@ -438,8 +438,9 @@ byte_compile(files, optimize=%r, force=%r,
             #   cfile - byte-compiled file
             #   dfile - purported source filename (same as 'file' by default)
             if optimize >= 0:
+                opt = '' if optimize == 0 else optimize
                 cfile = importlib.util.cache_from_source(
-                    file, debug_override=not optimize)
+                    file, optimization=opt)
             else:
                 cfile = importlib.util.cache_from_source(file)
             dfile = file