Re: [PATCH 4/6] cli: intialize crypto structure in show and reply

[Daniel Kahn Gillmor <dkg@fifthhorseman.net>]

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On 05/18/2012 04:20 AM, Jani Nikula wrote:
> We have -Wextra, which enables -Wmissing-field-initializers, which
> requires us to use full initialization of struct fields when doing
> regular, non-designated initialization. The point is that you might
> introduce subtle bugs if you added new struct fields and forgot to check
> the initializations. (This is why we have e.g. { 0, 0, 0, 0, 0 } instead
> of just { 0 } in the initialization of notmuch_opt_desc_t arrays.)

i think we can agree that this is the right choice.  We might even want
to discourage non-designated initializations entirely.

> IMHO the whole point of designated initializers is that the
> initialization is not vulnerable to struct changes, and you can pick
> which fields you choose to initialize explicitly. Also, it has the added
> benefit of documenting the fields that are initialized, without having
> to look at the struct definition.

Agreed.

> Do we now want to initialize all struct fields explicitly, everywhere,
> even when using designated initializers? Isn't that the question then?

I'm not sure it has to be this dramatic and "all or nothing".  For
example, it could be reasonable to explicitly initialize some subobjects
and not others.  For example, the notmuch_crypto_t jamie is proposing
would effectively encode the default setting for the --verify and
--decrypt flags.  I could see wanting to explicitly initialize those
default policy choices, even if they happen to be identical to the
implicit "zero"ing.

> Won't that maintain and promote the misconception that explicit
> initialization is required, when it's really not, failing to educate the
> non-experts and planting a seed of doubt in the experts...?

i see your point here, which is why i'm not arguing that all subobjects
need to be explicitly initialized all the time.

> It's not always clear whether something is a matter of taste, style, or
> language paradigm. If it feels like a paradigm, sticking with it
> ultimately benefits *both* perspectives.

yep, understood.

	--dkg


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