Issue #19235: Add new RecursionError exception. Patch by Georg Brandl.

Doc/c-api/exceptions.rst

@@ -683,12 +683,12 @@ recursion depth automatically).
    sets a :exc:`MemoryError` and returns a nonzero value.
 
    The function then checks if the recursion limit is reached.  If this is the
-   case, a :exc:`RuntimeError` is set and a nonzero value is returned.
+   case, a :exc:`RecursionError` is set and a nonzero value is returned.
    Otherwise, zero is returned.
 
    *where* should be a string such as ``" in instance check"`` to be
-   concatenated to the :exc:`RuntimeError` message caused by the recursion depth
-   limit.
+   concatenated to the :exc:`RecursionError` message caused by the recursion
+   depth limit.
 
 .. c:function:: void Py_LeaveRecursiveCall()
 
@@ -800,6 +800,8 @@ the variables:
 +-----------------------------------------+---------------------------------+----------+
 | :c:data:`PyExc_ProcessLookupError`      | :exc:`ProcessLookupError`       |          |
 +-----------------------------------------+---------------------------------+----------+
+| :c:data:`PyExc_RecursionError`          | :exc:`RecursionError`           |          |
++-----------------------------------------+---------------------------------+----------+
 | :c:data:`PyExc_ReferenceError`          | :exc:`ReferenceError`           | \(2)     |
 +-----------------------------------------+---------------------------------+----------+
 | :c:data:`PyExc_RuntimeError`            | :exc:`RuntimeError`             |          |
@@ -829,6 +831,9 @@ the variables:
    :c:data:`PyExc_PermissionError`, :c:data:`PyExc_ProcessLookupError`
    and :c:data:`PyExc_TimeoutError` were introduced following :pep:`3151`.
 
+.. versionadded:: 3.5
+   :c:data:`PyExc_RecursionError`.
+
 
 These are compatibility aliases to :c:data:`PyExc_OSError`:
 
@@ -877,6 +882,7 @@ These are compatibility aliases to :c:data:`PyExc_OSError`:
    single: PyExc_OverflowError
    single: PyExc_PermissionError
    single: PyExc_ProcessLookupError
+   single: PyExc_RecursionError
    single: PyExc_ReferenceError
    single: PyExc_RuntimeError
    single: PyExc_SyntaxError

Doc/library/exceptions.rst

@@ -282,6 +282,16 @@ The following exceptions are the exceptions that are usually raised.
    handling in C, most floating point operations are not checked.
 
 
+.. exception:: RecursionError
+
+   This exception is derived from :exc:`RuntimeError`.  It is raised when the
+   interpreter detects that the maximum recursion depth (see
+   :func:`sys.getrecursionlimit`) is exceeded.
+
+   .. versionadded:: 3.5
+      Previously, a plain :exc:`RuntimeError` was raised.
+
+
 .. exception:: ReferenceError
 
    This exception is raised when a weak reference proxy, created by the

Doc/library/pickle.rst

@@ -425,7 +425,7 @@ The following types can be pickled:
 Attempts to pickle unpicklable objects will raise the :exc:`PicklingError`
 exception; when this happens, an unspecified number of bytes may have already
 been written to the underlying file.  Trying to pickle a highly recursive data
-structure may exceed the maximum recursion depth, a :exc:`RuntimeError` will be
+structure may exceed the maximum recursion depth, a :exc:`RecursionError` will be
 raised in this case.  You can carefully raise this limit with
 :func:`sys.setrecursionlimit`.
 

Doc/whatsnew/3.5.rst

@@ -87,6 +87,8 @@ New built-in features:
 * Generators have new ``gi_yieldfrom`` attribute, which returns the
   object being iterated by ``yield from`` expressions. (Contributed
   by Benno Leslie and Yury Selivanov in :issue:`24450`.)
+* New :exc:`RecursionError` exception. (Contributed by Georg Brandl
+  in :issue:`19235`.)
 
 Implementation improvements: