[PATCH] checkpatch: Make "return is not a function" test quieter

[PATCH] checkpatch: Make "return is not a function" test quieter

[Joe Perches]

This test is a bit noisy and opinions seem to agree that
it should not warn in a lot more situations.

It seems people agree that:

	return (foo || bar);
and
	return foo || bar;

are both acceptable style and checkpatch should be silent
about them.

For now, it warns on parentheses around a simple constant
or a single function or a ternary.

	return (foo);
	return (foo(bar));
	return (foo ? bar : baz);

The last ternary test may be quieted in the future.

Modify the deparenthesize function to only strip balanced
leading and trailing parentheses.

Signed-off-by: Joe Perches <joe@perches.com>
---
 scripts/checkpatch.pl | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 91308be..be4be81 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -439,9 +439,14 @@ our $FuncArg = qr{$Typecast{0,1}($LvalOrFunc|$Constant)};
 sub deparenthesize {
 	my ($string) = @_;
 	return "" if (!defined($string));
-	$string =~ s@^\s*\(\s*@@g;
-	$string =~ s@\s*\)\s*$@@g;
+
+	while ($string =~ /^\s*\(.*\)\s*$/) {
+		$string =~ s@^\s*\(\s*@@;
+		$string =~ s@\s*\)\s*$@@;
+	}
+
 	$string =~ s@\s+@ @g;
+
 	return $string;
 }
 
@@ -3362,14 +3367,17 @@ sub process {
 			}
 		}
 
-# Return is not a function.
+# return is not a function
 		if (defined($stat) && $stat =~ /^.\s*return(\s*)\(/s) {
 			my $spacing = $1;
 			if ($^V && $^V ge 5.10.0 &&
-			    $stat =~ /^.\s*return\s*$balanced_parens\s*;\s*$/) {
-				ERROR("RETURN_PARENTHESES",
-				      "return is not a function, parentheses are not required\n" . $herecurr);
-
+			    $stat =~ /^.\s*return\s*($balanced_parens)\s*;\s*$/) {
+				my $value = $1;
+				$value = deparenthesize($value);
+				if ($value =~ m/^\s*$FuncArg\s*(?:\?|$)/) {
+					ERROR("RETURN_PARENTHESES",
+					      "return is not a function, parentheses are not required\n" . $herecurr);
+				}
 			} elsif ($spacing !~ /\s+/) {
 				ERROR("SPACING",
 				      "space required before the open parenthesis '('\n" . $herecurr);

Re: [OPW kernel] [PATCH] checkpatch: Make "return is not a function" test quieter

[josh]

On Thu, Feb 27, 2014 at 11:27:10AM -0800, Joe Perches wrote:
> This test is a bit noisy and opinions seem to agree that
> it should not warn in a lot more situations.
> 
> It seems people agree that:
> 
> 	return (foo || bar);
> and
> 	return foo || bar;
> 
> are both acceptable style and checkpatch should be silent
> about them.
> 
> For now, it warns on parentheses around a simple constant
> or a single function or a ternary.
> 
> 	return (foo);
> 	return (foo(bar));
> 	return (foo ? bar : baz);
> 
> The last ternary test may be quieted in the future.
> 
> Modify the deparenthesize function to only strip balanced
> leading and trailing parentheses.
> 
> Signed-off-by: Joe Perches <joe@perches.com>

I'd suggest dropping the warning for parenthesized ternaries as well,
but in any case:

Reviewed-by: Josh Triplett <josh@joshtriplett.org>

>  scripts/checkpatch.pl | 22 +++++++++++++++-------
>  1 file changed, 15 insertions(+), 7 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 91308be..be4be81 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -439,9 +439,14 @@ our $FuncArg = qr{$Typecast{0,1}($LvalOrFunc|$Constant)};
>  sub deparenthesize {
>  	my ($string) = @_;
>  	return "" if (!defined($string));
> -	$string =~ s@^\s*\(\s*@@g;
> -	$string =~ s@\s*\)\s*$@@g;
> +
> +	while ($string =~ /^\s*\(.*\)\s*$/) {
> +		$string =~ s@^\s*\(\s*@@;
> +		$string =~ s@\s*\)\s*$@@;
> +	}
> +
>  	$string =~ s@\s+@ @g;
> +
>  	return $string;
>  }
>  
> @@ -3362,14 +3367,17 @@ sub process {
>  			}
>  		}
>  
> -# Return is not a function.
> +# return is not a function
>  		if (defined($stat) && $stat =~ /^.\s*return(\s*)\(/s) {
>  			my $spacing = $1;
>  			if ($^V && $^V ge 5.10.0 &&
> -			    $stat =~ /^.\s*return\s*$balanced_parens\s*;\s*$/) {
> -				ERROR("RETURN_PARENTHESES",
> -				      "return is not a function, parentheses are not required\n" . $herecurr);
> -
> +			    $stat =~ /^.\s*return\s*($balanced_parens)\s*;\s*$/) {
> +				my $value = $1;
> +				$value = deparenthesize($value);
> +				if ($value =~ m/^\s*$FuncArg\s*(?:\?|$)/) {
> +					ERROR("RETURN_PARENTHESES",
> +					      "return is not a function, parentheses are not required\n" . $herecurr);
> +				}
>  			} elsif ($spacing !~ /\s+/) {
>  				ERROR("SPACING",
>  				      "space required before the open parenthesis '('\n" . $herecurr);
> 
> 
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