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Date:   Thu, 12 May 2022 12:26:33 -0500
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Subject: Re: [RFC] KTAP spec v2: prefix to KTAP data
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To:     Daniel Latypov <dlatypov@google.com>
Cc:     David Gow <davidgow@google.com>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Kees Cook <keescook@chromium.org>, Tim.Bird@sony.com,
        Brendan Higgins <brendanhiggins@google.com>,
        Jonathan Corbet <corbet@lwn.net>, rmr167@gmail.com,
        guillaume.tucker@collabora.com, kernelci@groups.io,
        kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
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From:   Frank Rowand <frowand.list@gmail.com>
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On 5/12/22 10:25, Daniel Latypov wrote:
> On Wed, May 11, 2022 at 11:01 PM Frank Rowand <frowand.list@gmail.com> wrote:
>> ================================================================================
>> #### discussion notes:
>>
>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>> PRO: minimally invasive to specification.
>>
>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>> CON:
>>
>> KTAP does not include any mechanism to describe the value of <prefix string>
>> to test harnesses and test output processing programs.  The test output
>> processing programs must infer the value of <prefix string> by detecting
>> the <prefix string> in the "Version lines".
>>
>> The detection of a "Version lines" might be a match of the regex:
>>
>>    "^.*KTAP version 2$"
>>
>> This risks falsely detecting a "Version lines", but the risk is small???
> 
> Agree this is a risk and also think it's probably small, but it's hard to say.
> I think the $ anchoring the regex is probably safe enough.
> 
> As noted earlier, this tracks with what kunit.py already does.
> That was necessitated by dynamic prefixes such as timestamps, etc.f

That is a good observation.  I nearly always have the prefix timestamp
on my console output, and thus remove the timestamp with a regex when
processing the data.

-Frank

> So I think this is probably a fine risk to take.
> 
> I imagine we could add constraints of prefix string, e.g. must have []
> around it, etc. if we want to try and minimize this risk.
> But I don't know if it's necessarily worth it, given what we know right now.
> 
> Along those lines, I think I like this approach (Alternative 1) more
> than Alternative 2/2b.
> I'm not sure we need a structured way to specify metadata in KTAP yet?
> The prefix seems like a reasonable candidate, but do others have ideas
> of other bits of metadata we'd want to be able to declare?
> 
> Daniel