Re: [PATCH] checkpatch: prefer = {} initializations to = {0}
From: Joe Perches <joe@perches.com>
Date: 2021-08-05 12:27:34
Also in:
lkml
Subsystem:
checkpatch, the rest · Maintainers:
Andy Whitcroft, Joe Perches, Linus Torvalds
On Thu, 2021-08-05 at 13:43 +0300, Dan Carpenter wrote:
The "= {};" style empty struct initializer is preferred over = {0}.
It avoids the situation where the first struct member is a pointer and
that generates a Sparse warning about assigning using zero instead of
NULL. Also it's just nicer to look at.
Some people complain that {} is less portable but the kernel has
different portability requirements from userspace so this is not a
issue that we care about.[]
quoted hunk ↗ jump to hunk
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
quoted hunk ↗ jump to hunk
@@ -4029,6 +4029,12 @@ sub process {"Using $1 is unnecessary\n" . $herecurr); } +# prefer = {}; to = {0}; + if ($line =~ /= \{ *0 *\}/) {
Have you done a grep and looked at this pattern's actual use in the kernel? I rather doubt it.
+ WARN("ZERO_INITIALIZER",
+ "= {} is preferred over = {0}\n" . $herecurr);
+ }
+
To be much more specific to the actual desired match as stated in
the possible commit log, this should probably be something like:
if (defined($stat) &&
$stat =~ /^\+\s+$Declare\s*$Ident\s*=\s*\{\s*0\s*\}\s*;/) {
and maybe it should be a --strict CHK and not WARN.
And I generally avoid using "we" in a commit message.
Maybe something like:
---
scripts/checkpatch.pl | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 461d4221e4a4a..e3d4aa5f86c46 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl@@ -6911,6 +6911,21 @@ sub process { "externs should be avoided in .c files\n" . $herecurr); } +# check for non-global single initializers with '= {0};', prefer '= {};' +# there is already a GLOBAL_INITIALIZERS test so avoid those too with /^\+\s+/ + if (defined($stat) && + $stat =~ /^\+\s+$Declare\s*$Ident\s*(=\s*\{\s*0\s*\}\s*);/) { + my $match = $1; + my $cnt = statement_rawlines($stat); + my $herectx = get_stat_here($linenr, $cnt, $here); + if (WARN("ZERO_INITIALIZER", + "Prefer '= {}' over '$match'\n" . $herectx) && + $fix && + $cnt == 1) { # can only --fix single line statements + $fixed[$fixlinenr] =~ s/\s*=\s*\{\s*0\s*\}\s*;/ = {};/; + } + } + # check for function declarations that have arguments without identifier names if (defined $stat && $stat =~ /^.\s*(?:extern\s+)?$Type\s*(?:$Ident|\(\s*\*\s*$Ident\s*\))\s*\(\s*([^{]+)\s*\)\s*;/s &&