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Code Issues Projects Releases Packages Wiki Activity Actions 15

Issue #15767: Use ModuleNotFoundError.

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Eric Snow 2016-09-07 16:56:15 -07:00
parent c943265ba5
commit 46f97b85a8
16 changed files with 337 additions and 284 deletions
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Doc/reference/import.rst
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@ -36,7 +36,7 @@ implement import semantics.
When a module is first imported, Python searches for the module and if found,
it creates a module object [#fnmo]_, initializing it. If the named module
cannot be found, an :exc:`ImportError` is raised. Python implements various
cannot be found, an :exc:`ModuleNotFoundError` is raised. Python implements various
strategies to search for the named module when the import machinery is
invoked. These strategies can be modified and extended by using various hooks
described in the sections below.
@ -167,7 +167,7 @@ arguments to the :keyword:`import` statement, or from the parameters to the
This name will be used in various phases of the import search, and it may be
the dotted path to a submodule, e.g. ``foo.bar.baz``. In this case, Python
first tries to import ``foo``, then ``foo.bar``, and finally ``foo.bar.baz``.
If any of the intermediate imports fail, an :exc:`ImportError` is raised.
If any of the intermediate imports fail, an :exc:`ModuleNotFoundError` is raised.
The module cache
@ -186,7 +186,7 @@ object.
During import, the module name is looked up in :data:`sys.modules` and if
present, the associated value is the module satisfying the import, and the
process completes. However, if the value is ``None``, then an
:exc:`ImportError` is raised. If the module name is missing, Python will
:exc:`ModuleNotFoundError` is raised. If the module name is missing, Python will
continue searching for the module.
:data:`sys.modules` is writable. Deleting a key may not destroy the
@ -194,7 +194,7 @@ associated module (as other modules may hold references to it),
but it will invalidate the cache entry for the named module, causing
Python to search anew for the named module upon its next
import. The key can also be assigned to ``None``, forcing the next import
of the module to result in an :exc:`ImportError`.
of the module to result in an :exc:`ModuleNotFoundError`.
Beware though, as if you keep a reference to the module object,
invalidate its cache entry in :data:`sys.modules`, and then re-import the
@ -288,8 +288,8 @@ the named module or not.
If the meta path finder knows how to handle the named module, it returns a
spec object. If it cannot handle the named module, it returns ``None``. If
:data:`sys.meta_path` processing reaches the end of its list without returning
a spec, then an :exc:`ImportError` is raised. Any other exceptions raised
are simply propagated up, aborting the import process.
a spec, then a :exc:`ModuleNotFoundError` is raised. Any other exceptions
raised are simply propagated up, aborting the import process.
The :meth:`~importlib.abc.MetaPathFinder.find_spec()` method of meta path
finders is called with two or three arguments. The first is the fully
@ -298,9 +298,9 @@ The second argument is the path entries to use for the module search. For
top-level modules, the second argument is ``None``, but for submodules or
subpackages, the second argument is the value of the parent package's
``__path__`` attribute. If the appropriate ``__path__`` attribute cannot
be accessed, an :exc:`ImportError` is raised. The third argument is an
existing module object that will be the target of loading later. The
import system passes in a target module only during reload.
be accessed, an :exc:`ModuleNotFoundError` is raised. The third argument
is an existing module object that will be the target of loading later.
The import system passes in a target module only during reload.
The meta path may be traversed multiple times for a single import request.
For example, assuming none of the modules involved has already been cached,
@ -887,7 +887,7 @@ import statements within that module.
To selectively prevent import of some modules from a hook early on the
meta path (rather than disabling the standard import system entirely),
it is sufficient to raise :exc:`ImportError` directly from
it is sufficient to raise :exc:`ModuleNoFoundError` directly from
:meth:`~importlib.abc.MetaPathFinder.find_spec` instead of returning
``None``. The latter indicates that the meta path search should continue,
while raising an exception terminates it immediately.