Improve byte-compilation in packaging to be independent of -O or -B.

The code I fixed to comply with PEP 3147 still had one bug: When run
under python -O, some paths for pyc files would be pyo, because I called
imp.cache_from_source without explicit debug_override argument in some
places, and under -O that would return .pyo (this is well explained in
the imp docs).  Now all code (util.byte_compile, build_py, install_lib)
can create .pyo files according to options given by users,
without interference from the calling Python’s own optimize mode.

On a related topic, I also removed the code that prevented byte
compilation under python -B.  The rationale is that packaging gives
control over the creation of pyc files to the user with its own explicit
option, and the behavior should not be changed if the calling Python
happens to run with -B for whatever reason.  I will argue that this is a
bug fix and ask to be allowed to backport this change to distutils.

Finally, I moved one nugget of information about the --compile and
--optimize options from the source into the doc.  It clears up a
misunderstanding that I (and maybe other people) had.

1 files changed, 12 insertions, 28 deletions

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 @@ from packaging.errors import PackagingOptionError
 
 
 # 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 @@ class install_lib(Command):
 
     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 @@ class install_lib(Command):
         ]
 
     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 @@ class install_lib(Command):
         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 @@ class install_lib(Command):
         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 @@ class install_lib(Command):
         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 @@ class install_lib(Command):
             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)