From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:43476) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gkXM9-00088b-By for qemu-devel@nongnu.org; Fri, 18 Jan 2019 11:50:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gkXM8-0006ep-6x for qemu-devel@nongnu.org; Fri, 18 Jan 2019 11:50:57 -0500 Received: from mail-wr1-x42b.google.com ([2a00:1450:4864:20::42b]:36032) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gkXM8-0006bw-0O for qemu-devel@nongnu.org; Fri, 18 Jan 2019 11:50:56 -0500 Received: by mail-wr1-x42b.google.com with SMTP id u4so15875764wrp.3 for ; Fri, 18 Jan 2019 08:50:55 -0800 (PST) From: Peter Maydell Date: Fri, 18 Jan 2019 16:50:50 +0000 Message-Id: <20190118165050.22270-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v2] checkpatch: Don't emit spurious warnings about block comments List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: patches@linaro.org, Thomas Huth , Eric Blake In checkpatch we attempt to check for and warn about block comments which start with /* or /** followed by a non-blank. Unfortunately a bug in the regex meant that we would incorrectly warn about comments starting with "/**" with no following text: git show 9813dc6ac3954d58ba16b3920556f106f97e1c67|./scripts/checkpatch.pl - WARNING: Block comments use a leading /* on a separate line #34: FILE: tests/libqtest.h:233: +/** The sequence "/\*\*?" was intended to match either "/*" or "/**", but Perl's semantics for '?' allow it to backtrack and try the "matches 0 chars" option if the "matches 1 char" choice leads to a failure of the rest of the regex to match. Switch to "/\*\*?+" which uses what perlre(1) calls the "possessive" quantifier form: this means that if it matches the "/**" string it will not later backtrack to matching just the "/*" prefix. The other end of the regex is also wrong: it is attempting to check for "/* or /** followed by something that isn't just whitespace", but [ \t]*.+[ \t]* will match on pure whitespace. This is less significant but means that a line with just a comment-starter followed by trailing whitespace will generate an incorrect warning about block comment style as well as the correct error about trailing whitespace which a different checkpatch test emits. Reported-by: Thomas Huth Reported-by: Eric Blake Signed-off-by: Peter Maydell --- This comment check is unique to QEMU checkpatch so the bugs don't exist in the Linux version. v1->v2 changes: Add the fix to the other end of the regex pointed out by Eric, so that we don't emit spurious warnings for block comment starters with trailing whitespace. --- scripts/checkpatch.pl | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index d10dddf1be4..88682cb0a9f 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -1624,7 +1624,7 @@ sub process { # Block comments use /* on a line of its own if ($rawline !~ m@^\+.*/\*.*\*/[ \t]*$@ && #inline /*...*/ - $rawline =~ m@^\+.*/\*\*?[ \t]*.+[ \t]*$@) { # /* or /** non-blank + $rawline =~ m@^\+.*/\*\*?+[ \t]*[^ \t]@) { # /* or /** non-blank WARN("Block comments use a leading /* on a separate line\n" . $herecurr); } -- 2.20.1