From 58b3f111767148e9011ccd52660e208f0c834b2a Mon Sep 17 00:00:00 2001 From: Danny Yang Date: Wed, 19 Jun 2024 14:49:00 -0400 Subject: [PATCH] gh-120521: clarify except* documentation to allow tuples (#120523) Co-authored-by: Jelle Zijlstra Co-authored-by: Irit Katriel <1055913+iritkatriel@users.noreply.github.com> --- Doc/reference/compound_stmts.rst | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst index 42cca0664df..8181b975951 100644 --- a/Doc/reference/compound_stmts.rst +++ b/Doc/reference/compound_stmts.rst @@ -245,13 +245,12 @@ handler is started. This search inspects the :keyword:`!except` clauses in turn until one is found that matches the exception. An expression-less :keyword:`!except` clause, if present, must be last; it matches any exception. -For an :keyword:`!except` clause with an expression, -that expression is evaluated, and the clause matches the exception -if the resulting object is "compatible" with the exception. An object is -compatible with an exception if the object is the class or a -:term:`non-virtual base class ` of the exception object, -or a tuple containing an item that is the class or a non-virtual base class -of the exception object. + +For an :keyword:`!except` clause with an expression, the +expression must evaluate to an exception type or a tuple of exception types. +The raised exception matches an :keyword:`!except` clause whose expression evaluates +to the class or a :term:`non-virtual base class ` of the exception object, +or to a tuple that contains such a class. If no :keyword:`!except` clause matches the exception, the search for an exception handler @@ -378,8 +377,10 @@ exception group with an empty message string. :: ... ExceptionGroup('', (BlockingIOError())) -An :keyword:`!except*` clause must have a matching type, -and this type cannot be a subclass of :exc:`BaseExceptionGroup`. +An :keyword:`!except*` clause must have a matching expression; it cannot be ``except*:``. +Furthermore, this expression cannot contain exception group types, because that would +have ambiguous semantics. + It is not possible to mix :keyword:`except` and :keyword:`!except*` in the same :keyword:`try`. :keyword:`break`, :keyword:`continue` and :keyword:`return`