Re: [PATCH 13/17] qapi: Relax doc string @name: description indentation rules

[Juan Quintela]

Markus Armbruster <armbru@redhat.com> wrote:
> The QAPI schema doc comment language provides special syntax for
> command and event arguments, struct and union members, alternate
> branches, enumeration values, and features: descriptions starting with
> "@name:".
>
> By convention, we format them like this:
>
>     # @name: Lorem ipsum dolor sit amet, consectetur adipiscing elit,
>     #        sed do eiusmod tempor incididunt ut labore et dolore
>     #        magna aliqua.
>
> Okay for names as short as "name", but we have much longer ones.  Their
> description gets squeezed against the right margin, like this:
>
>     # @dirty-sync-missed-zero-copy: Number of times dirty RAM synchronization 
> could
>     #                               not avoid copying dirty pages. This is 
> between
>     #                               0 and @dirty-sync-count * 
> @multifd-channels.
>     #                               (since 7.1)
>
> The description text is effectively just 50 characters wide.  Easy
> enough to read, but can be cumbersome to write.
>
> The awkward squeeze against the right margin makes people go beyond it,
> which produces two undesirables: arguments about style, and descriptions
> that are unnecessarily hard to read, like this one:
>
>     # @postcopy-vcpu-blocktime: list of the postcopy blocktime per vCPU.  
> This is
>     #                           only present when the postcopy-blocktime 
> migration capability
>     #                           is enabled. (Since 3.0)
>
> We could instead format it like
>
>     # @postcopy-vcpu-blocktime:
>     # list of the postcopy blocktime per vCPU.  This is only present
>     # when the postcopy-blocktime migration capability is
>     # enabled. (Since 3.0)
>
> or, since the commit before previous, like
>
>     # @postcopy-vcpu-blocktime:
>     #           list of the postcopy blocktime per vCPU.  This is only present
>     #           when the postcopy-blocktime migration capability is
>     #           enabled. (Since 3.0)
>
> However, I'd rather have
>
>     # @postcopy-vcpu-blocktime: list of the postcopy blocktime per vCPU.
>     #     This is only present when the postcopy-blocktime migration
>     #     capability is enabled.  (Since 3.0)
>
> because this is how rST field and option lists work.
>
> To get this, we need to let the first non-blank line after the
> "@name:" line determine expected indentation.
>
> This fills up the indentation pitfall mentioned in
> docs/devel/qapi-code-gen.rst.  A related pitfall still exists.  Update
> the text to show it.
>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

> ---
>  docs/devel/qapi-code-gen.rst          | 10 ++--
>  scripts/qapi/parser.py                | 73 +++++++--------------------
>  tests/qapi-schema/doc-bad-indent.err  |  2 +-
>  tests/qapi-schema/doc-bad-indent.json |  3 +-

bad order of files

>  tests/qapi-schema/doc-good.json       |  3 +-
>  tests/qapi-schema/doc-good.out        |  3 +-

good order of files

Should we tweak orderfiles so it displays first the json, and the err or
out files. reviewing json and then output makes things (at least to me)
simpler.