Messages in this thread Patch in this message | | | Date | Mon, 21 Mar 2022 17:39:18 +0200 (EET) | From | Ilpo Järvinen <> | Subject | [PATCH v3 1/1] checkpatch: don't suggest else is not useful with chained if blocks |
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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> ---
v2: - Don't match spuriously to removed lines - Extend check backwards to the first line with the same or lower indent as "else" line
v3: - Add back the check to ensure line is defined
scripts/checkpatch.pl | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index b01c36a15d9d..3ea73155c42b 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -4037,14 +4037,24 @@ 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" 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/)) { - WARN("UNNECESSARY_ELSE", - "else is not generally useful after a break or return\n" . $hereprev); + my $ifline = $linenr - 3; + $tabs--; + while ($ifline >= 1 && + $lines[$ifline] !~ /^[^-]\t{0,$tabs}[^\t]/) { + $ifline--; + } + if (!defined $lines[$ifline] || + $lines[$ifline] !~ /^[\+ ]\t{$tabs,$tabs}(\} *|)else if\s*\(/) { + WARN("UNNECESSARY_ELSE", + "else is not generally useful after a break or return\n" . $hereprev); + } } } -- 2.30.2 | |