linux-kernel - Re: [PATCH 25/26] rv/rvgen: fix isinstance check in Variable.expand()

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Message-ID: <87wm19hcds.fsf@yellow.woof>
Date: Thu, 22 Jan 2026 16:53:51 +0100
From: Nam Cao <namcao@...utronix.de>
To: Wander Lairson Costa <wander@...hat.com>, Steven Rostedt
 <rostedt@...dmis.org>, Gabriele Monaco <gmonaco@...hat.com>, Wander
 Lairson Costa <wander@...hat.com>, open list
 <linux-kernel@...r.kernel.org>, "open list:RUNTIME VERIFICATION (RV)"
 <linux-trace-kernel@...r.kernel.org>
Subject: Re: [PATCH 25/26] rv/rvgen: fix isinstance check in Variable.expand()

Wander Lairson Costa <wander@...hat.com> writes:
> The Variable.expand() method in ltl2ba.py performs contradiction
> detection by checking if a negated variable already exists in the
> graph node's old set. However, the isinstance check was incorrectly
> testing the ASTNode wrapper instead of the wrapped operator, causing
> the check to always return False.
>
> The old set contains ASTNode instances which wrap LTL operators via
> their .op attribute. The fix changes isinstance(f, NotOp) to
> isinstance(f.op, NotOp) to correctly examine the wrapped operator
> type. This follows the established pattern used elsewhere in the
> file, such as the iteration at lines 572-574 which accesses
> o.op.is_temporal() on items from node.old.
>
> Signed-off-by: Wander Lairson Costa <wander@...hat.com>

These isinstance() usages deserve to be buried. But I'm not sure yet how
to replace them. So, for now:

Reviewed-by: Nam Cao <namcao@...utronix.de>