diff options
Diffstat (limited to 'Doc/library/runpy.rst')
| -rw-r--r-- | Doc/library/runpy.rst | 69 |
1 files changed, 41 insertions, 28 deletions
diff --git a/Doc/library/runpy.rst b/Doc/library/runpy.rst index 6919bc0c37..ee9fbcf529 100644 --- a/Doc/library/runpy.rst +++ b/Doc/library/runpy.rst @@ -44,28 +44,22 @@ The :mod:`runpy` module provides two functions: below are defined in the supplied dictionary, those definitions are overridden by :func:`run_module`. - The special global variables ``__name__``, ``__file__``, ``__cached__``, - ``__loader__`` - and ``__package__`` are set in the globals dictionary before the module - code is executed (Note that this is a minimal set of variables - other - variables may be set implicitly as an interpreter implementation detail). + The special global variables ``__name__``, ``__spec__``, ``__file__``, + ``__cached__``, ``__loader__`` and ``__package__`` are set in the globals + dictionary before the module code is executed (Note that this is a + minimal set of variables - other variables may be set implicitly as an + interpreter implementation detail). ``__name__`` is set to *run_name* if this optional argument is not :const:`None`, to ``mod_name + '.__main__'`` if the named module is a package and to the *mod_name* argument otherwise. - ``__file__`` is set to the name provided by the module loader. If the - loader does not make filename information available, this variable is set - to :const:`None`. + ``__spec__`` will be set appropriately for the *actually* imported + module (that is, ``__spec__.name`` will always be *mod_name* or + ``mod_name + '.__main__``, never *run_name*). - ``__cached__`` will be set to ``None``. - - ``__loader__`` is set to the :pep:`302` module loader used to retrieve the - code for the module (This loader may be a wrapper around the standard - import mechanism). - - ``__package__`` is set to *mod_name* if the named module is a package and - to ``mod_name.rpartition('.')[0]`` otherwise. + ``__file__``, ``__cached__``, ``__loader__`` and ``__package__`` are + :ref:`set as normal <import-mod-attrs>` based on the module spec. If the argument *alter_sys* is supplied and evaluates to :const:`True`, then ``sys.argv[0]`` is updated with the value of ``__file__`` and @@ -83,8 +77,13 @@ The :mod:`runpy` module provides two functions: Added ability to execute packages by looking for a ``__main__`` submodule. .. versionchanged:: 3.2 - Added ``__cached__`` global variable (see :PEP:`3147`). + Added ``__cached__`` global variable (see :pep:`3147`). + .. versionchanged:: 3.4 + Updated to take advantage of the module spec feature added by + :pep:`451`. This allows ``__cached__`` to be set correctly for modules + run this way, as well as ensuring the real module name is always + accessible as ``__spec__.name``. .. function:: run_path(file_path, init_globals=None, run_name=None) @@ -108,23 +107,28 @@ The :mod:`runpy` module provides two functions: below are defined in the supplied dictionary, those definitions are overridden by :func:`run_path`. - The special global variables ``__name__``, ``__file__``, ``__loader__`` - and ``__package__`` are set in the globals dictionary before the module - code is executed (Note that this is a minimal set of variables - other - variables may be set implicitly as an interpreter implementation detail). + The special global variables ``__name__``, ``__spec__``, ``__file__``, + ``__cached__``, ``__loader__`` and ``__package__`` are set in the globals + dictionary before the module code is executed (Note that this is a + minimal set of variables - other variables may be set implicitly as an + interpreter implementation detail). ``__name__`` is set to *run_name* if this optional argument is not :const:`None` and to ``'<run_path>'`` otherwise. - ``__file__`` is set to the name provided by the module loader. If the - loader does not make filename information available, this variable is set - to :const:`None`. For a simple script, this will be set to ``file_path``. + If the supplied path directly references a script file (whether as source + or as precompiled byte code), then ``__file__`` will be set to the + supplied path, and ``__spec__``, ``__cached__``, ``__loader__`` and + ``__package__`` will all be set to :const:`None`. - ``__loader__`` is set to the :pep:`302` module loader used to retrieve the - code for the module (This loader may be a wrapper around the standard - import mechanism). For a simple script, this will be set to :const:`None`. + ``__spec__`` will be set to :const:`None` if the supplied path is a + direct path to a script (as source or as precompiled bytecode). - ``__package__`` is set to ``__name__.rpartition('.')[0]``. + If the supplied path is a reference to a valid sys.path entry, then + ``__spec__`` will be set appropriately for the imported ``__main__`` + module (that is, ``__spec__.name`` will always be ``__main__``). + ``__file__``, ``__cached__``, ``__loader__`` and ``__package__`` will be + :ref:`set as normal <import-mod-attrs>` based on the module spec. A number of alterations are also made to the :mod:`sys` module. Firstly, ``sys.path`` may be altered as described above. ``sys.argv[0]`` is updated @@ -141,6 +145,12 @@ The :mod:`runpy` module provides two functions: .. versionadded:: 3.2 + .. versionchanged:: 3.4 + Updated to take advantage of the module spec feature added by + :pep:`451`. This allows ``__cached__`` to be set correctly in the + case where ``__main__`` is imported from a valid sys.path entry rather + than being executed directly. + .. seealso:: :pep:`338` - Executing modules as scripts @@ -149,6 +159,9 @@ The :mod:`runpy` module provides two functions: :pep:`366` - Main module explicit relative imports PEP written and implemented by Nick Coghlan. + :pep:`451` - A ModuleSpec Type for the Import System + PEP written and implemented by Eric Snow + :ref:`using-on-general` - CPython command line details The :func:`importlib.import_module` function |