Re: [PATCH] checkpatch: skip macros when finding missing switch/case break

Re: [PATCH] checkpatch: skip macros when finding missing switch/case break

[Cambda Zhu]

I agree with you. Actually there are some false warnings not mentioned in my patch, such as:

case xxx: {
   if () {
       return;
   } else {
           if () {
               return;
           } else {
               return;
           }
   }
}
case xxx:
   ...

Since compiler can do this now, I think this test should be removed.

Regards,
Cambda

> 在 2020年8月1日，02:05，Joe Perches <joe@perches.com> 写道：
> 
> On Wed, 2020-07-29 at 20:59 +0800, Cambda Zhu wrote:
>> The checkpatch.pl only searches 3 previous lines when finding missing
>> switch/case break, and macros are treated as normal statements. If the
>> cases are surrounded with CONFIG, checkpatch.pl may report false
>> warnings. For example:
> 
> Likely this test should be removed altogether as
> it's never really worked well and now compilers
> find this and emit warnings.

[PATCH] checkpatch: Remove missing switch/case break test

[Joe Perches]

This test doesn't work well and newer compilers are much better
at emitting this warning.

Signed-off-by: Joe Perches <joe@perches.com>
---
> 在 2020年8月1日，02:05，Joe Perches <joe@perches.com> 写道：
> > On Wed, 2020-07-29 at 20:59 +0800, Cambda Zhu wrote:
> > > The checkpatch.pl only searches 3 previous lines when finding missing
> > > switch/case break, and macros are treated as normal statements. If the
> > > cases are surrounded with CONFIG, checkpatch.pl may report false
> > > warnings. For example:
> > 
> > Likely this test should be removed altogether as
> > it's never really worked well and now compilers
> > find this and emit warnings.

 scripts/checkpatch.pl | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index cc5542cc234f..4aa1d9d5e62c 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6541,31 +6541,6 @@ sub process {
 			}
 		}
 
-# check for case / default statements not preceded by break/fallthrough/switch
-		if ($line =~ /^.\s*(?:case\s+(?:$Ident|$Constant)\s*|default):/) {
-			my $has_break = 0;
-			my $has_statement = 0;
-			my $count = 0;
-			my $prevline = $linenr;
-			while ($prevline > 1 && ($file || $count < 3) && !$has_break) {
-				$prevline--;
-				my $rline = $rawlines[$prevline - 1];
-				my $fline = $lines[$prevline - 1];
-				last if ($fline =~ /^\@\@/);
-				next if ($fline =~ /^\-/);
-				next if ($fline =~ /^.(?:\s*(?:case\s+(?:$Ident|$Constant)[\s$;]*|default):[\s$;]*)*$/);
-				$has_break = 1 if ($rline =~ /fall[\s_-]*(through|thru)/i);
-				next if ($fline =~ /^.[\s$;]*$/);
-				$has_statement = 1;
-				$count++;
-				$has_break = 1 if ($fline =~ /\bswitch\b|\b(?:break\s*;[\s$;]*$|exit\s*\(\b|return\b|goto\b|continue\b)/);
-			}
-			if (!$has_break && $has_statement) {
-				WARN("MISSING_BREAK",
-				     "Possible switch case/default not preceded by break or fallthrough comment\n" . $herecurr);
-			}
-		}
-
 # check for /* fallthrough */ like comment, prefer fallthrough;
 		my @fallthroughs = (
 			'fallthrough',