From f4bdc13e492208f4f9cad0ff1c14247dea1cd197 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 1 Dec 2017 17:24:33 -0600 Subject: [PATCH] checkpatch: Enforce proper do/while (0) style Use of a loop construct for code that is not intended to repeat does not make much idiomatic sense, except in one place: it is a common usage in macros in order to wrap arbitrary code with single-statement semantics. But when used in a macro, it is more typical for the caller to supply the trailing ';' when calling the macro. Although qemu coding style frowns on bare: if (cond) statement1; else statement2; where extra semicolons actually cause syntax errors, we still want our macro styles to be easily copied to other projects. Thus, declare it an error if we encounter any form of 'while (0)' with a semicolon in the same line. Signed-off-by: Eric Blake Message-Id: <20171201232433.25193-8-eblake@redhat.com> Signed-off-by: Paolo Bonzini --- scripts/checkpatch.pl | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 3dc27d9656..accba24a31 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -1622,6 +1622,11 @@ sub process { } } +# 'do ... while (0/false)' only makes sense in macros, without trailing ';' + if ($line =~ /while\s*\((0|false)\);/) { + ERROR("suspicious ; after while (0)\n" . $herecurr); + } + # Check relative indent for conditionals and blocks. if ($line =~ /\b(?:(?:if|while|for)\s*\(|do\b)/ && $line !~ /^.\s*#/ && $line !~ /\}\s*while\s*/) { my ($s, $c) = ($stat, $cond);