linux-kernel - Re: scripts/checkpatch: Concatenated strings should use spaces between elements

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Message-ID: <88fabf5b-7240-8f89-2c46-38cf29010aa2@gmx.de>
Date:   Wed, 18 Oct 2017 08:32:19 +0200
From:   Heinrich Schuchardt <xypron.glpk@....de>
To:     Joe Perches <joe@...ches.com>, Andy Whitcroft <apw@...onical.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: scripts/checkpatch: Concatenated strings should use spaces
 between elements

On 10/18/2017 02:35 AM, Joe Perches wrote:
> On Wed, 2017-10-18 at 00:58 +0200, Heinrich Schuchardt wrote:
>> On 10/18/2017 12:43 AM, Joe Perches wrote:
>>> On Tue, 2017-10-17 at 23:17 +0200, Heinrich Schuchardt wrote:
>>>> This patch creates a warning (CHECK)
>>>> "Concatenated strings should use spaces between elements"
> []
>>>> +void foo(void)
>>>> +{
>>>> +	test(L"\"");
>>>
>>> In this case, L must be a constant string and you
>>> are concatenating L and "\""
>>>
>>>
>>
>> See ISO/IEC 9899:1999
>>
>> 6.4.5 String literals
>>
>> <cite>
>> A character string literal is a sequence of zero or more multibyte
>> characters enclosed in double-quotes, as in "xyz"
>> A wide  string  literal is  the  same, except prefixed by the
>> letter L.
>> </cite>
>>
>> L"foo" is a literal of type wchar_t * and not two strings.
>> L is a qualifier and not a constant string.
>>
>> Just like ULL in 10ULL.
> 
> How about trying this:
> 
>>>From 99bd0ab78a810f537e18a24be42379a6af9d5045 Mon Sep 17 00:00:00 2001
> Message-Id: <99bd0ab78a810f537e18a24be42379a6af9d5045.1508286849.git.joe@...ches.com>
> From: Joe Perches <joe@...ches.com>
> Date: Tue, 17 Oct 2017 17:11:14 -0700
> Subject: [PATCH] checkpatch: Support wide strings
> 
> Allow prefixing typical strings with L for wide strings
> 
> Signed-off-by: Joe Perches <joe@...ches.com>
> ---
>  scripts/checkpatch.pl | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 359c02b0954e..9f04f803e96b 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -393,7 +393,7 @@ our $Binary	= qr{(?i)0b[01]+$Int_type?};
>  our $Hex	= qr{(?i)0x[0-9a-f]+$Int_type?};
>  our $Int	= qr{[0-9]+$Int_type?};
>  our $Octal	= qr{0[0-7]+$Int_type?};
> -our $String	= qr{"[X\t]*"};
> +our $String	= qr{(?:\bL)?"[X\t]*"};
>  our $Float_hex	= qr{(?i)0x[0-9a-f]+p-?[0-9]+[fl]?};
>  our $Float_dec	= qr{(?i)(?:[0-9]+\.[0-9]*|[0-9]*\.[0-9]+)(?:e-?[0-9]+)?[fl]?};
>  our $Float_int	= qr{(?i)[0-9]+e-?[0-9]+[fl]?};
> @@ -5262,13 +5262,14 @@ sub process {
>  		}
>  
>  # concatenated string without spaces between elements
> -		if ($line =~ /$String[A-Z_]/ || $line =~ /[A-Za-z0-9_]$String/) {
> +		if ($line =~ /$String[A-Z_]/ ||
> +		    ($line =~ /([A-Za-z0-9_]+)$String/ && $1 !~ /^L$/)) {
>  			CHK("CONCATENATED_STRING",
>  			    "Concatenated strings should use spaces between elements\n" . $herecurr);
>  		}
>  
>  # uncoalesced string fragments
> -		if ($line =~ /$String\s*"/) {
> +		if ($line =~ /$String\s*L?"/) {
>  			WARN("STRING_FRAGMENTS",
>  			     "Consecutive strings are generally better as a single string\n" . $herecurr);
>  		}
> -- 
> 2.10.0.rc2.1.g053435c
> 
> 
The patch solves my problem.

Thank you.

Best regards

Heinrich