Re: [RFC][PATCH] kconfig: introduce listunknownconfig

From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nicolas Schier <nicolas@fjasle.eu>,
	Jonathan Corbet <corbet@lwn.net>,
	Tomasz Figa <tfiga@chromium.org>,
	linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] kconfig: introduce listunknownconfig
Date: Sun, 20 Aug 2023 11:45:19 +0900	[thread overview]
Message-ID: <20230820024519.GK907732@google.com> (raw)
In-Reply-To: <CAK7LNASJWKSsdzn5ccgWaC35-XvHGU7pnE6C=eZFDbqrrghtdQ@mail.gmail.com>

On (23/08/20 08:19), Masahiro Yamada wrote:
> > Example:
> > Suppose old .config has the following two options which
> > were removed from the recent kernel:
> >
> > $ cat .config
> > CONFIG_DISABLE_BUGS=y
> >
> > Running `make listunknownconfig` produces the following
> > list of unrecognized symbols:
> >
> > .config:6:warning: unknown symbol: DISABLE_BUGS
> > .config:7:warning: unknown unset symbol: ENABLE_WINAPI
> >
> > Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> 
> 
> A new target is not what I like to see.
> 
> 
> We decided to add KCONFIG_VERBOSE, which will be used to
> warn options accidentally disabled or downgraded.

That doesn't seem cover the cases that I'm concerned with. I don't see
anything related to "!sym" in the patch.

What will KCONFIG_VERBOSE do if it reads the following config file?

// assuming that both config options were valid and existed in the old
// kernel, but were removed/renamed in the new kernel

 $ cat .config
 CONFIG_DISABLE_BUGS=y
 # CONFIG_ENABLE_WINAPI is not set

I'd like to see warnings for both lines, even for config that is not
set, because it maybe we set by a build script depending on USE flags
for instance, so that build target may still refer to non-existent
config.