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Date:   Tue, 10 Oct 2023 18:11:16 +0200 (CEST)
From:   Julia Lawall <julia.lawall@inria.fr>
To:     Anton Eliasson <anton.eliasson@axis.com>
cc:     Nicolas Palix <nicolas.palix@imag.fr>, cocci@inria.fr,
        linux-kernel@vger.kernel.org, kernel@axis.com
Subject: Re: [cocci] [PATCH 2/2] scripts: coccicheck: Separate spatch stdout
 and stderr
In-Reply-To: <5c76da14-e34e-afbd-4265-493c66e0bc60@axis.com>
Message-ID: <b37c26-154a-2db9-4944-26a8aa8af7af@inria.fr>
References: <20231003-coccicheck-v1-0-07d2d900a52a@axis.com> <20231003-coccicheck-v1-2-07d2d900a52a@axis.com> <alpine.DEB.2.22.394.2310072140340.36842@hadrien> <5c76da14-e34e-afbd-4265-493c66e0bc60@axis.com>
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On Tue, 10 Oct 2023, Anton Eliasson wrote:

> On 07/10/2023 21.41, Julia Lawall wrote:
> >
> > On Tue, 3 Oct 2023, Anton Eliasson wrote:
> >
> > > This helps automating coccicheck runs by discarding stderr and only
> > > looking at the output of stdout. In report mode the only remaining
> > > output on stdout is the initial "Please check for false positives"
> > > message followed by each spatch warning found.
> > What is getting dropped is the spatch command lines indicating the
> > semantic patch.  Is this desirable?
> >
> > julia
> It's not ideal but it's the best compromise that I have found. The problem I'm
> trying to solve is to be able to diff the output of two coccicheck runs and
> notify the developer if any new warnings were introduced. That requires the
> output to be stable. spatch is always invoked for each cocci file in the same
> order. However, the output from each spatch invocation is not stable as it
> examines each source file in an arbitrary order.
>
> My workaround is to sort the output before diffing. The line-by-line sorted
> output only makes sense if the input is one line per warning found and that is
> why I try to discard all output except the single line per spatch warning.
> While the terse output doesn't tell which semantic patch file generated the
> warning, it does usually contain the offending file, line number and a summary
> of the issue.

Why does the command line pose a problem for sorting?

julia

>
>
> Anton
> >
> > > Signed-off-by: Anton Eliasson <anton.eliasson@axis.com>
> > > ---
> > >   scripts/coccicheck | 4 ++--
> > >   1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/scripts/coccicheck b/scripts/coccicheck
> > > index 95a312730e98..7e7c44125f47 100755
> > > --- a/scripts/coccicheck
> > > +++ b/scripts/coccicheck
> > > @@ -146,8 +146,8 @@ run_cmd_parmap() {
> > >                   echo $@>>$DEBUG_FILE
> > >                   $@ 2>>$DEBUG_FILE
> > >           else
> > > -                echo $@
> > > -                $@ 2>&1
> > > +                echo $@ >&2
> > > +                $@
> > >   	fi
> > >
> > >   	err=$?
> > >
> > > --
> > > 2.30.2
> > >
> > >
>
>