Re: [PATCH v4 05/31] scripts: add script to fix error_append_hint/error_prepend usage

[Eric Blake]

On 10/1/19 10:52 AM, Vladimir Sementsov-Ogievskiy wrote:
> error_append_hint and error_prepend will not work, if errp ==
> &fatal_error, as program will exit before error_append_hint or
> error_prepend call. Fix this by use of special macro
> ERRP_AUTO_PROPAGATE.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---

> +++ b/scripts/coccinelle/fix-error-add-info.cocci
> @@ -0,0 +1,28 @@
> +@rule0@
> +// Add invocation to errp-functions
> +identifier fn;
> +@@
> +
> + fn(..., Error **errp, ...)
> + {

When running this script, I get lots of warnings:

init_defs_builtins: /usr/lib64/coccinelle/standard.h
warning: line 6: should errp be a metavariable?
warning: line 11: should errp be a metavariable?
warning: line 13: should errp be a metavariable?
HANDLING: include/block/nbd.h

This means we are trying to patch only an actual variable named 'errp', 
and not a meta-variable representing any variable of type Error ** 
regardless of whether it is named errp or something else.  I think 
that's okay, in part because ERRP_AUTO_PROPAGATE() expects the exact 
name 'errp' to be in scope, so we cannot apply it to other variable 
names).  But I still have to wonder if there is a way to silence the 
warning, or if we have any outliers (other than the intentional Error 
**errp_in in patch 1) using a different name for a parameter of type 
Error **, which should also be tweaked.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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