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

Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com> (cherry picked from commit 8be7c2b) Co-authored-by: Dave Goncalves <davegoncalves@gmail.com>

Author: miss-islington

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.
 

Doc/reference/datamodel.rst

@@ -2913,7 +2913,8 @@ 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

Doc/reference/expressions.rst

@@ -556,14 +556,27 @@ 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
 
 

Objects/genobject.c

@@ -403,8 +403,11 @@ 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,
@@ -1001,8 +1004,11 @@ 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.");