Messages in this thread Patch in this message | | | Date | Mon, 21 Mar 2022 11:18:06 +0200 (EET) | From | Ilpo Järvinen <> | Subject | [RFC PATCH 1/1] checkpatch: don't suggest else is not useful with chained |
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When if blocks are chained with "else if" like this:
if (a) c = 0; else if (b) break; else c = 1;
checkpatch recommends removing else:
WARNING: else is not generally useful after a break or return
Removing else will easily introduce logic errors in this situation so it's better to check if the preceding line has "else if" before issuing that warning.
Fixes: 032a4c0f9a77 ("checkpatch: warn on unnecessary else after return or break") Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> ---
I was only able to solve this case for single line if blocks but it would be useful to address also multi-line if blocks but it is beyond my understanding about checkpatch internals.
scripts/checkpatch.pl | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index b01c36a15d9d..8e095b77bfb6 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -4037,14 +4037,17 @@ sub process { # check indentation of any line with a bare else # (but not if it is a multiple line "if (foo) return bar; else return baz;") # if the previous line is a break or return and is indented 1 tab more... +# but don't warn when there is "else if" on before that line to avoid logic errors if ($sline =~ /^\+([\t]+)(?:}[ \t]*)?else(?:[ \t]*{)?\s*$/) { my $tabs = length($1) + 1; - if ($prevline =~ /^\+\t{$tabs,$tabs}break\b/ || - ($prevline =~ /^\+\t{$tabs,$tabs}return\b/ && - defined $lines[$linenr] && - $lines[$linenr] !~ /^[ \+]\t{$tabs,$tabs}return/)) { + if ($linenr >= 3 && + $lines[$linenr - 3] !~ /[} \t]else\s+if\s*\(/ && + ($prevline =~ /^\+\t{$tabs,$tabs}break\b/ || + ($prevline =~ /^\+\t{$tabs,$tabs}return\b/ && + defined $lines[$linenr] && + $lines[$linenr] !~ /^[ \+]\t{$tabs,$tabs}return/))) { WARN("UNNECESSARY_ELSE", - "else is not generally useful after a break or return\n" . $hereprev); + "else is not generally useful after a break or return\n" . $hereprev . "\n"); } } -- 2.30.2 | |