checkpatch: add a --strict test for comparison to true/false
Comparing to true or false is error prone.
Add tests for the various forms of (foo == true) && (false != bar)
that are only reported with --strict.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index c43be81..c2d223c 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3588,6 +3588,33 @@
"Using yield() is generally wrong. See yield() kernel-doc (sched/core.c)\n" . $herecurr);
}
+# check for comparisons against true and false
+ if ($line =~ /\+\s*(.*?)\b(true|false|$Lval)\s*(==|\!=)\s*(true|false|$Lval)\b(.*)$/i) {
+ my $lead = $1;
+ my $arg = $2;
+ my $test = $3;
+ my $otype = $4;
+ my $trail = $5;
+ my $op = "!";
+
+ ($arg, $otype) = ($otype, $arg) if ($arg =~ /^(?:true|false)$/i);
+
+ my $type = lc($otype);
+ if ($type =~ /^(?:true|false)$/) {
+ if (("$test" eq "==" && "$type" eq "true") ||
+ ("$test" eq "!=" && "$type" eq "false")) {
+ $op = "";
+ }
+
+ CHK("BOOL_COMPARISON",
+ "Using comparison to $otype is error prone\n" . $herecurr);
+
+## maybe suggesting a correct construct would better
+## "Using comparison to $otype is error prone. Perhaps use '${lead}${op}${arg}${trail}'\n" . $herecurr);
+
+ }
+ }
+
# check for semaphores initialized locked
if ($line =~ /^.\s*sema_init.+,\W?0\W?\)/) {
WARN("CONSIDER_COMPLETION",