Re: [RFC] KTAP spec v2: prefix to KTAP data

[Daniel Latypov <dlatypov@google.com>]

On Wed, May 11, 2022 at 11:01 PM Frank Rowand <frowand.list@gmail.com> wrote:
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> #### discussion notes:
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> PRO: minimally invasive to specification.
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> CON:
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> 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.
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