mirror of
https://github.com/python/cpython.git
synced 2024-11-26 11:24:40 +08:00
a6b3ec5b6d
Unconditional forcing of ``CHECKED_HASH`` invalidation was introduced in 3.7.0 in bpo-29708. The change is bad, as it unconditionally overrides *invalidation_mode*, even if it was passed as an explicit argument to ``py_compile.compile()`` or ``compileall``. An environment variable should *never* override an explicit argument to a library function. That change leads to multiple test failures if the ``SOURCE_DATE_EPOCH`` environment variable is set. This changes ``py_compile.compile()`` to only look at ``SOURCE_DATE_EPOCH`` if no explicit *invalidation_mode* was specified. I also made various relevant tests run with explicit control over the value of ``SOURCE_DATE_EPOCH``. While looking at this, I noticed that ``zipimport`` does not work with hash-based .pycs _at all_, though I left the fixes for subsequent commits.
139 lines
5.9 KiB
ReStructuredText
139 lines
5.9 KiB
ReStructuredText
:mod:`py_compile` --- Compile Python source files
|
|
=================================================
|
|
|
|
.. module:: py_compile
|
|
:synopsis: Generate byte-code files from Python source files.
|
|
|
|
.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
|
|
.. documentation based on module docstrings
|
|
|
|
**Source code:** :source:`Lib/py_compile.py`
|
|
|
|
.. index:: pair: file; byte-code
|
|
|
|
--------------
|
|
|
|
The :mod:`py_compile` module provides a function to generate a byte-code file
|
|
from a source file, and another function used when the module source file is
|
|
invoked as a script.
|
|
|
|
Though not often needed, this function can be useful when installing modules for
|
|
shared use, especially if some of the users may not have permission to write the
|
|
byte-code cache files in the directory containing the source code.
|
|
|
|
|
|
.. exception:: PyCompileError
|
|
|
|
Exception raised when an error occurs while attempting to compile the file.
|
|
|
|
|
|
.. function:: compile(file, cfile=None, dfile=None, doraise=False, optimize=-1, invalidation_mode=PycInvalidationMode.TIMESTAMP)
|
|
|
|
Compile a source file to byte-code and write out the byte-code cache file.
|
|
The source code is loaded from the file named *file*. The byte-code is
|
|
written to *cfile*, which defaults to the :pep:`3147`/:pep:`488` path, ending
|
|
in ``.pyc``.
|
|
For example, if *file* is ``/foo/bar/baz.py`` *cfile* will default to
|
|
``/foo/bar/__pycache__/baz.cpython-32.pyc`` for Python 3.2. If *dfile* is
|
|
specified, it is used as the name of the source file in error messages when
|
|
instead of *file*. If *doraise* is true, a :exc:`PyCompileError` is raised
|
|
when an error is encountered while compiling *file*. If *doraise* is false
|
|
(the default), an error string is written to ``sys.stderr``, but no exception
|
|
is raised. This function returns the path to byte-compiled file, i.e.
|
|
whatever *cfile* value was used.
|
|
|
|
If the path that *cfile* becomes (either explicitly specified or computed)
|
|
is a symlink or non-regular file, :exc:`FileExistsError` will be raised.
|
|
This is to act as a warning that import will turn those paths into regular
|
|
files if it is allowed to write byte-compiled files to those paths. This is
|
|
a side-effect of import using file renaming to place the final byte-compiled
|
|
file into place to prevent concurrent file writing issues.
|
|
|
|
*optimize* controls the optimization level and is passed to the built-in
|
|
:func:`compile` function. The default of ``-1`` selects the optimization
|
|
level of the current interpreter.
|
|
|
|
*invalidation_mode* should be a member of the :class:`PycInvalidationMode`
|
|
enum and controls how the generated bytecode cache is invalidated at
|
|
runtime. The default is :attr:`PycInvalidationMode.CHECKED_HASH` if
|
|
the :envvar:`SOURCE_DATE_EPOCH` environment variable is set, otherwise
|
|
the default is :attr:`PycInvalidationMode.TIMESTAMP`.
|
|
|
|
.. versionchanged:: 3.2
|
|
Changed default value of *cfile* to be :PEP:`3147`-compliant. Previous
|
|
default was *file* + ``'c'`` (``'o'`` if optimization was enabled).
|
|
Also added the *optimize* parameter.
|
|
|
|
.. versionchanged:: 3.4
|
|
Changed code to use :mod:`importlib` for the byte-code cache file writing.
|
|
This means file creation/writing semantics now match what :mod:`importlib`
|
|
does, e.g. permissions, write-and-move semantics, etc. Also added the
|
|
caveat that :exc:`FileExistsError` is raised if *cfile* is a symlink or
|
|
non-regular file.
|
|
|
|
.. versionchanged:: 3.7
|
|
The *invalidation_mode* parameter was added as specified in :pep:`552`.
|
|
If the :envvar:`SOURCE_DATE_EPOCH` environment variable is set,
|
|
*invalidation_mode* will be forced to
|
|
:attr:`PycInvalidationMode.CHECKED_HASH`.
|
|
|
|
.. versionchanged:: 3.7.2
|
|
The :envvar:`SOURCE_DATE_EPOCH` environment variable no longer
|
|
overrides the value of the *invalidation_mode* argument, and determines
|
|
its default value instead.
|
|
|
|
|
|
.. class:: PycInvalidationMode
|
|
|
|
A enumeration of possible methods the interpreter can use to determine
|
|
whether a bytecode file is up to date with a source file. The ``.pyc`` file
|
|
indicates the desired invalidation mode in its header. See
|
|
:ref:`pyc-invalidation` for more information on how Python invalidates
|
|
``.pyc`` files at runtime.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
.. attribute:: TIMESTAMP
|
|
|
|
The ``.pyc`` file includes the timestamp and size of the source file,
|
|
which Python will compare against the metadata of the source file at
|
|
runtime to determine if the ``.pyc`` file needs to be regenerated.
|
|
|
|
.. attribute:: CHECKED_HASH
|
|
|
|
The ``.pyc`` file includes a hash of the source file content, which Python
|
|
will compare against the source at runtime to determine if the ``.pyc``
|
|
file needs to be regenerated.
|
|
|
|
.. attribute:: UNCHECKED_HASH
|
|
|
|
Like :attr:`CHECKED_HASH`, the ``.pyc`` file includes a hash of the source
|
|
file content. However, Python will at runtime assume the ``.pyc`` file is
|
|
up to date and not validate the ``.pyc`` against the source file at all.
|
|
|
|
This option is useful when the ``.pycs`` are kept up to date by some
|
|
system external to Python like a build system.
|
|
|
|
|
|
.. function:: main(args=None)
|
|
|
|
Compile several source files. The files named in *args* (or on the command
|
|
line, if *args* is ``None``) are compiled and the resulting byte-code is
|
|
cached in the normal manner. This function does not search a directory
|
|
structure to locate source files; it only compiles files named explicitly.
|
|
If ``'-'`` is the only parameter in args, the list of files is taken from
|
|
standard input.
|
|
|
|
.. versionchanged:: 3.2
|
|
Added support for ``'-'``.
|
|
|
|
When this module is run as a script, the :func:`main` is used to compile all the
|
|
files named on the command line. The exit status is nonzero if one of the files
|
|
could not be compiled.
|
|
|
|
|
|
.. seealso::
|
|
|
|
Module :mod:`compileall`
|
|
Utilities to compile all Python source files in a directory tree.
|