Re: [PATCH] checkpatch: warn if <foo.h> is already included

[Joe Perches <joe@perches.com>]

On Thu, 2016-11-24 at 22:45 +0800, Geliang Tang wrote:
> Some headers are included twice. Emit a warning when they occur.
> For example:
> $ ./scripts/checkpatch.pl -f drivers/of/overlay.c
> WARNING: Do not use #include <linux/string.h>, this header is already included
> +#include <linux/string.h>
> 
> WARNING: Do not use #include <linux/string.h>, this header is already included
> +#include <linux/string.h>
> 
> total: 0 errors, 4 warnings, 589 lines checked

There already is a script that looks for duplicate #include
uses so I think this isn't particularly useful or necessary.
see: scripts/checkincludes.h

Also, this doesn't work when reordering #include lines.
.
> Signed-off-by: Geliang Tang <geliangtang@gmail.com>
> ---
>  scripts/checkpatch.pl | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 1579230..a0792d6 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -4749,6 +4749,18 @@ sub process {
>  			}
>  		}
>  
> +# warn if <foo.h> is already #included
> +		if ($tree && $rawline =~ m{^.\s*\#\s*include\s*\<(.*)\.h\>}) {
> +			my $file = "$1.h";
> +			if (-f "$root/$realfile") {
> +				my $asminclude = `grep -Ec "#include\\s+<$file>" $root/$realfile`;
> +				if ($asminclude > 1) {
> +					WARN("INCLUDE_LINUX",
> +					     "Do not use #include <$file>, this header is already included\n" . $herecurr);
> +				}
> +			}
> +		}
> +
>  # multi-statement macros should be enclosed in a do while loop, grab the
>  # first statement and ensure its the whole macro if its not enclosed
>  # in a known good container