Re: [PATCH v3] coccinelle: add style check for assignment in if

From: Julia Lawall
Date: Tue Feb 23 2016 - 09:00:55 EST




On Mon, 22 Feb 2016, Kris Borer wrote:

> Add a semantic patch for fixing some cases of checkpatch.pl error:
>
> ERROR: do not use assignment in if condition
>
> Signed-off-by: Kris Borer <kborer@xxxxxxxxx>

Acked-by: Julia Lawall <julia.lawall@xxxxxxx>

> ---
> changes since v2
> - added comment warning that changes may not work well with ifdefs
>
> scripts/coccinelle/style/assignment_in_if.cocci | 132 ++++++++++++++++++++++++
> 1 file changed, 132 insertions(+)
> create mode 100644 scripts/coccinelle/style/assignment_in_if.cocci
>
> diff --git a/scripts/coccinelle/style/assignment_in_if.cocci b/scripts/coccinelle/style/assignment_in_if.cocci
> new file mode 100644
> index 0000000..c99cd7e
> --- /dev/null
> +++ b/scripts/coccinelle/style/assignment_in_if.cocci
> @@ -0,0 +1,132 @@
> +/// move assignments out of if conditions
> +///
> +//# This script is designed to correct code where assignments exist in if
> +//# conditions. It is only capable of handling a subset of such problems.
> +//# Ideally it would handle all checkpatch errors of the following type:
> +//# ERROR: do not use assignment in if condition
> +//#
> +//# For example:
> +//# if(result = myfun())
> +//#
> +//# would become:
> +//# result = myfun();
> +//# if(result)
> +//#
> +//# note:
> +//# added braces due to the replacement of an if by multiple statements
> +//# may not interact well with ifdefs
> +//
> +// Confidence: Moderate
> +// Copyright: (C) 2015 Kris Borer. GPLv2.
> +// URL: http://coccinelle.lip6.fr/
> +// Comments:
> +// Options: --no-includes --include-headers
> +
> +virtual patch
> +
> +
> +// if ( (ret = call()) )
> +// if ( (ret = call()) < 0 )
> +@if1@
> +expression i;
> +expression E, E2;
> +statement S1, S2;
> +binary operator b;
> +@@
> +
> ++ i = E;
> + if (
> +(
> +- (i = E)
> ++ i
> +|
> +- (i = E)
> ++ i
> + b ...
> +|
> +- (i = E),
> + E2
> +)
> + ) S1 else S2
> +
> +
> +// if ( ptr->fun && (ret = ptr->fun()) )
> +@if2@
> +expression i2;
> +expression E1, E2;
> +@@
> +
> ++ if( E1 ) {
> ++ i2 = E2;
> ++ if (i2) {
> +- if( E1 && (i2 = E2) ) {
> + ...
> +- }
> ++ }
> ++ }
> +
> +
> +// if ( ptr->fun && (ret = ptr->fun()) < 0 )
> +@if3@
> +expression i2;
> +expression E1, E2;
> +constant c;
> +binary operator b;
> +@@
> +
> ++ if( E1 ) {
> ++ i2 = E2;
> ++ if (i2 b c) {
> +- if( E1 && ((i2 = E2) b c) ) {
> + ...
> +- }
> ++ }
> ++ }
> +
> +
> +// if ( (ret = call()) && ret != -1 )
> +// if ( (ret = call()) < 0 && ret != -1 )
> +@if4@
> +expression i;
> +expression E, E2;
> +statement S1, S2;
> +binary operator b;
> +@@
> +
> ++ i = E;
> + if (
> +(
> +- (i = E)
> ++ i
> +|
> + (
> +- (i = E)
> ++ i
> + b
> + ...)
> +)
> + && E2 ) S1 else S2
> +
> +
> +// if ( (ret = call()) && ret != -1 && ret != -2 )
> +// if ( (ret = call()) < 0 && ret != -1 && ret != -2 )
> +@if5@
> +expression i;
> +expression E, E2, E3;
> +statement S1, S2;
> +binary operator b;
> +@@
> +
> ++ i = E;
> + if (
> +(
> +- (i = E)
> ++ i
> +|
> + (
> +- (i = E)
> ++ i
> + b
> + ...)
> +)
> + && E2 && E3 ) S1 else S2
> --
> 1.9.1
>
>