[123/156] checkpatch: add test for comma use that should be semicolon

Commit Message

Andrew Morton Oct. 16, 2020, 2:48 a.m. UTC

From: Joe Perches <[e-mail]>
Subject: checkpatch: add test for comma use that should be semicolon

There are commas used as statement terminations that should typically have
used semicolons instead.  Only direct assignments or use of a single
function or value on a single line are detected by this test.

e.g.:
	foo = bar(),		/* typical use is semicolon not comma */
	bar = baz();

Add an imperfect test to detect these comma uses.

No false positives were found in testing, but many types of false
negatives are possible.

e.g.:
	foo = bar() + 1,	/* comma use, but not direct assignment */
	bar = baz();

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Joe Perches <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 scripts/checkpatch.pl |   11 +++++++++++
 1 file changed, 11 insertions(+)

Patch

--- a/scripts/checkpatch.pl~checkpatch-add-test-for-comma-use-that-should-be-semicolon
+++ a/scripts/checkpatch.pl
@@ -4940,6 +4940,17 @@  sub process {
 			}
 		}
 
+# check if a statement with a comma should be two statements like:
+#	foo = bar(),	/* comma should be semicolon */
+#	bar = baz();
+		if (defined($stat) &&
+		    $stat =~ /^\+\s*(?:$Lval\s*$Assignment\s*)?$FuncArg\s*,\s*(?:$Lval\s*$Assignment\s*)?$FuncArg\s*;\s*$/) {
+			my $cnt = statement_rawlines($stat);
+			my $herectx = get_stat_here($linenr, $cnt, $here);
+			WARN("SUSPECT_COMMA_SEMICOLON",
+			     "Possible comma where semicolon could be used\n" . $herectx);
+		}
+
 # return is not a function
 		if (defined($stat) && $stat =~ /^.\s*return(\s*)\(/s) {
 			my $spacing = $1;