* [PATCH v2 1/1] checkpatch: don't suggest else is not useful with chained
@ 2022-03-21 15:30 Ilpo Järvinen
0 siblings, 0 replies; only message in thread
From: Ilpo Järvinen @ 2022-03-21 15:30 UTC (permalink / raw)
To: Joe Perches; +Cc: Andy Whitcroft, Dwaipayan Ray, Lukas Bulwahn, LKML
[-- Attachment #1: Type: text/plain, Size: 2007 bytes --]
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
scripts/checkpatch.pl | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index b01c36a15d9d..ec0d9ac7e555 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4037,14 +4037,23 @@ 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]/) {
+ $ifline--;
+ }
+ if ($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
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