[PATCH] checkpatch: Add exception to return then else test

From: Joe Perches
Date: Thu Sep 25 2014 - 01:04:01 EST


Add an exception to the return before else warning
when the line following it is also a return like:

if (foo)
return bar;
else
return baz;

This form of a test then return is at least as readable as

if (foo)
return bar;
return baz;

so don't emit a warning on the first form.

Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
> > Just what makes the replacement easier to follow?
> > if (foo)
> > return bar;
> > else
> > return baz;
> > is no less idiomatic than
> > if (foo)
> > return bar;
> > return baz;
> >
> > Al, really annoyed by how the words "coding style issue" are getting used as
> > a magic incantation...
>
> I agree.
>
> I'll see about updating checkpatch to avoid warning on it

scripts/checkpatch.pl | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 74bba23..52a223e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2641,10 +2641,14 @@ sub process {
next if ($realfile !~ /\.(h|c)$/);

# 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...
if ($sline =~ /^\+([\t]+)(?:}[ \t]*)?else(?:[ \t]*{)?\s*$/) {
my $tabs = length($1) + 1;
- if ($prevline =~ /^\+\t{$tabs,$tabs}(?:break|return)\b/) {
+ 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);
}


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