Re: [PATCH 23/46] qapi: Smooth error checking with Coccinelle

From: Eric Blake <eblake@redhat.com>
To: Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, vsementsov@virtuozzo.com,
	berrange@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org,
	pbonzini@redhat.com
Subject: Re: [PATCH 23/46] qapi: Smooth error checking with Coccinelle
Date: Wed, 24 Jun 2020 15:50:38 -0500	[thread overview]
Message-ID: <c1fed52d-ff57-c366-c35d-271a0a1d724c@redhat.com> (raw)
In-Reply-To: <20200624164344.3778251-24-armbru@redhat.com>

On 6/24/20 11:43 AM, Markus Armbruster wrote:
> The previous commit enables conversion of
> 
>      visit_foo(..., &err);
>      if (err) {
> 	...
>      }
> 
> to
> 
>      if (!visit_foo(..., errp)) {
> 	...
>      }
> 
> for visitor functions that now return true / false on success / error.
> Coccinelle script:
> 
>      @@
>      identifier fun =~ "check_list|input_type_enum|lv_start_struct|lv_type_bool|lv_type_int64|lv_type_str|lv_type_uint64|output_type_enum|parse_type_bool|parse_type_int64|parse_type_null|parse_type_number|parse_type_size|parse_type_str|parse_type_uint64|print_type_bool|print_type_int64|print_type_null|print_type_number|print_type_size|print_type_str|print_type_uint64|qapi_clone_start_alternate|qapi_clone_start_list|qapi_clone_start_struct|qapi_clone_type_bool|qapi_clone_type_int64|qapi_clone_type_null|qapi_clone_type_number|qapi_clone_type_str|qapi_clone_type_uint64|qapi_dealloc_start_list|qapi_dealloc_start_struct|qapi_dealloc_type_anything|qapi_dealloc_type_bool|qapi_dealloc_type_int64|qapi_dealloc_type_null|qapi_dealloc_type_number|qapi_dealloc_type_str|qapi_dealloc_type_uint64|qobject_input_check_list|qobject_input_check_struct|qobject_input_start_alternate|qobject_input_start_list|qobject_input_start_struct|qobject_input_type_any|qobject_input_type_bool|qobject_input_type_bool_keyval|qobject_input_type_int64|qobject_input_type_int64_keyval|qobject_input_type_null|qobject_input_type_number|qobject_input_type_number_keyval|qobject_input_type_size_keyval|qobject_input_type_str|qobject_input_type_str_keyval|qobject_input_type_uint64|qobject_input_type_uint64_keyval|qobject_output_start_list|qobject_output_start_struct|qobject_output_type_any|qobject_output_type_bool|qobject_output_type_int64|qobject_output_type_null|qobject_output_type_number|qobject_output_type_str|qobject_output_type_uint64|start_list|visit_check_list|visit_check_struct|visit_start_alternate|visit_start_list|visit_start_struct|visit_type_.*";

Long line. Does coccinelle understand \-newline wrapping?

>      expression list args, args2;
>      typedef Error;
>      Error *err;
>      identifier errp;
>      @@
>      -      fun(args, &err, args2);
>      -      if (err) {
>      +      if (!fun(args, errp, args2)) {
> 	       ... when != err
>      -	   error_propagate(errp, err);
> 	       ...
> 	   }
> 
>      @@
>      identifier fun =~ "check_list|input_type_enum|lv_start_struct|lv_type_bool|lv_type_int64|lv_type_str|lv_type_uint64|output_type_enum|parse_type_bool|parse_type_int64|parse_type_null|parse_type_number|parse_type_size|parse_type_str|parse_type_uint64|print_type_bool|print_type_int64|print_type_null|print_type_number|print_type_size|print_type_str|print_type_uint64|qapi_clone_start_alternate|qapi_clone_start_list|qapi_clone_start_struct|qapi_clone_type_bool|qapi_clone_type_int64|qapi_clone_type_null|qapi_clone_type_number|qapi_clone_type_str|qapi_clone_type_uint64|qapi_dealloc_start_list|qapi_dealloc_start_struct|qapi_dealloc_type_anything|qapi_dealloc_type_bool|qapi_dealloc_type_int64|qapi_dealloc_type_null|qapi_dealloc_type_number|qapi_dealloc_type_str|qapi_dealloc_type_uint64|qobject_input_check_list|qobject_input_check_struct|qobject_input_start_alternate|qobject_input_start_list|qobject_input_start_struct|qobject_input_type_any|qobject_input_type_bool|qobject_input_type_bool_keyval|qobject_input_type_int64|qobject_input_type_int64_keyval|qobject_input_type_null|qobject_input_type_number|qobject_input_type_number_keyval|qobject_input_type_size_keyval|qobject_input_type_str|qobject_input_type_str_keyval|qobject_input_type_uint64|qobject_input_type_uint64_keyval|qobject_output_start_list|qobject_output_start_struct|qobject_output_type_any|qobject_output_type_bool|qobject_output_type_int64|qobject_output_type_null|qobject_output_type_number|qobject_output_type_str|qobject_output_type_uint64|start_list|visit_check_list|visit_check_struct|visit_start_alternate|visit_start_list|visit_start_struct|visit_type_.*";

The same list twice.  Is there a way to write it only once, then refer 
to it by reference in the two halves of the script?

>   46 files changed, 95 insertions(+), 331 deletions(-)

Nice to see the size reduction.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org