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From:   Daniel Latypov <dlatypov@google.com>
Date:   Fri, 20 May 2022 15:35:13 -0700
Message-ID: <CAGS_qxpF338dvbB+6QW1n8_agddeS10+nkTQNmT+0UcvoE1gBw@mail.gmail.com>
Subject: Re: [PATCH] kunit: tool: refactor internal kconfig handling, allow overriding
To:     David Gow <davidgow@google.com>
Cc:     Brendan Higgins <brendanhiggins@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        KUnit Development <kunit-dev@googlegroups.com>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        Shuah Khan <skhan@linuxfoundation.org>
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On Fri, May 20, 2022 at 3:13 PM Daniel Latypov <dlatypov@google.com> wrote:
> Talking offline with David, we've come up with a small example.
>
> If we add this kconfig somewhere
> +config X
> +       bool "X"
> +       default y
> +
> +config Y
> +       bool "Y"
> +       default y
> +       depends on X
> +
>
> Then running this will fail
> $ ./tools/testing/kunit/kunit.py config --kunitconfig xy_kunitconfig
> --kconfig_add=CONFIG_X=n --kconfig_add=CONFIG_Y=n
>
> It will fail with this
> This is probably due to unsatisfied dependencies.
> Missing: # CONFIG_Y is not set
>
> The problem is that kunit.py is looking for an explicit line saying
> CONFIG_Y is not set.
> But CONFIG_Y's dependencies are not met, so Kconfig doesn't write it out.
>
> I assume we can treat the absence of it in the file as proof that it's not set.
> I.e. the bug lies in the is_subset() logic we have in kunit.py?

Ah no, this is just me trying to be clever and avoid a call to this logic.
I tried to use set_diff() and check if that's empty as an alternative.
But the set_diff() logic is not aware of how to treat the absence of
options properly.

I'll send a v2 w/ a fix.