checkpatch: check for if's with unnecessary parentheses

If statements don't need multiple parentheses around tested comparisons like "if ((foo == bar))". An == comparison maybe a sign of an intended assignment, so emit a slightly different message if so. Signed-off-by: Joe Perches <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Cc: Manfred Spraul <[email protected]> Cc: Andy Whitcroft <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
chewitt · Jan 24, 2014 · 189248d · 189248d
1 parent c76f4cb
commit 189248d
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
@@ -3254,6 +3254,20 @@ sub process {
 			}
 		}
 
+# if statements using unnecessary parentheses - ie: if ((foo == bar))
+		if ($^V && $^V ge 5.10.0 &&
+		    $line =~ /\bif\s*((?:\(\s*){2,})/) {
+			my $openparens = $1;
+			my $count = $openparens =~ tr@\(@\(@;
+			my $msg = "";
+			if ($line =~ /\bif\s*(?:\(\s*){$count,$count}$LvalOrFunc\s*($Compare)\s*$LvalOrFunc(?:\s*\)){$count,$count}/) {
+				my $comp = $4;	#Not $1 because of $LvalOrFunc
+				$msg = " - maybe == should be = ?" if ($comp eq "==");
+				WARN("UNNECESSARY_PARENTHESES",
+				     "Unnecessary parentheses$msg\n" . $herecurr);
+			}
+		}
+
 # Return of what appears to be an errno should normally be -'ve
 		if ($line =~ /^.\s*return\s*(E[A-Z]*)\s*;/) {
 			my $name = $1;