[Python-checkins] bpo-14911: Corrected generator.throw() documentation (GH-32207)

[miss-islington]

https://github.com/python/cpython/commit/98d57737de73342d33d1b90dc0285f586465d22b
commit: 98d57737de73342d33d1b90dc0285f586465d22b
branch: 3.9
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2022-03-31T07:24:39-07:00
summary:

bpo-14911: Corrected generator.throw() documentation (GH-32207)


Co-authored-by: Andrew Svetlov <andrew.svetlov at gmail.com>
(cherry picked from commit 8be7c2bc5ad5e295f0f855bb31db412eef2c7c92)

Co-authored-by: Dave Goncalves <davegoncalves at gmail.com>

files:
M Doc/howto/functional.rst
M Doc/reference/datamodel.rst
M Doc/reference/expressions.rst
M Objects/genobject.c

diff --git a/Doc/howto/functional.rst b/Doc/howto/functional.rst
index c7f8bc8f17f43..695b9b31a762b 100644
--- a/Doc/howto/functional.rst
+++ b/Doc/howto/functional.rst
@@ -589,7 +589,7 @@ generator function.
 In addition to :meth:`~generator.send`, there are two other methods on
 generators:
 
-* :meth:`throw(type, value=None, traceback=None) <generator.throw>` is used to
+* :meth:`throw(value) <generator.throw>` is used to
   raise an exception inside the generator; the exception is raised by the
   ``yield`` expression where the generator's execution is paused.
 
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index 84320f41f6cae..033d65fd7c90f 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -2854,7 +2854,8 @@ generators, coroutines do not directly support iteration.
    :exc:`StopIteration`, or other exception) is the same as when
    iterating over the :meth:`__await__` return value, described above.
 
-.. method:: coroutine.throw(type[, value[, traceback]])
+.. method:: coroutine.throw(value)
+            coroutine.throw(type[, value[, traceback]])
 
    Raises the specified exception in the coroutine.  This method delegates
    to the :meth:`~generator.throw` method of the iterator that caused
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 4ffb6512107f2..502c022501eff 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -557,14 +557,27 @@ is already executing raises a :exc:`ValueError` exception.
    could receive the value.
 
 
-.. method:: generator.throw(type[, value[, traceback]])
+.. method:: generator.throw(value)
+            generator.throw(type[, value[, traceback]])
 
-   Raises an exception of type ``type`` at the point where the generator was paused,
+   Raises an exception at the point where the generator was paused,
    and returns the next value yielded by the generator function.  If the generator
    exits without yielding another value, a :exc:`StopIteration` exception is
    raised.  If the generator function does not catch the passed-in exception, or
    raises a different exception, then that exception propagates to the caller.
 
+   In typical use, this is called with a single exception instance similar to the
+   way the :keyword:`raise` keyword is used.
+
+   For backwards compatability, however, the second signature is
+   supported, following a convention from older versions of Python.
+   The *type* argument should be an exception class, and *value*
+   should be an exception instance. If the *value* is not provided, the
+   *type* constructor is called to get an instance. If *traceback*
+   is provided, it is set on the exception, otherwise any existing
+   :attr:`~BaseException.__traceback__` attribute stored in *value* may
+   be cleared.
+
 .. index:: exception: GeneratorExit
 
 
diff --git a/Objects/genobject.c b/Objects/genobject.c
index 5ba4de82ea70e..95614729c8fab 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -384,8 +384,11 @@ gen_close(PyGenObject *gen, PyObject *args)
 
 
 PyDoc_STRVAR(throw_doc,
-"throw(typ[,val[,tb]]) -> raise exception in generator,\n\
-return next yielded value or raise StopIteration.");
+"throw(value)\n\
+throw(type[,value[,tb]])\n\
+\n\
+Raise exception in generator, return next yielded value or raise\n\
+StopIteration.");
 
 static PyObject *
 _gen_throw(PyGenObject *gen, int close_on_genexit,
@@ -943,8 +946,11 @@ PyDoc_STRVAR(coro_send_doc,
 return next iterated value or raise StopIteration.");
 
 PyDoc_STRVAR(coro_throw_doc,
-"throw(typ[,val[,tb]]) -> raise exception in coroutine,\n\
-return next iterated value or raise StopIteration.");
+"throw(value)\n\
+throw(type[,value[,traceback]])\n\
+\n\
+Raise exception in coroutine, return next iterated value or raise\n\
+StopIteration.");
 
 PyDoc_STRVAR(coro_close_doc,
 "close() -> raise GeneratorExit inside coroutine.");