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checkpatch: Adapt the braces check to Zephyr

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scripts/checkpatch.pl was written originally for the Linux kernel, and
its code reflects the kernel's coding style. In particular, it has
checks for unneeded braces around single-statement if/else/for/while
conditions. In Zephyr however, braces are always required, and so the
checks needed modifying to verify the opposite condition.

In order to enable the now-compatible checks, we also remove the
--ignore BRACES statement in .checkpatch.conf.

Limitations: the current code works well if there are not conditional
statements (e.g. #if, #ifdef or #endif) next to the if/else/for/while
conditions. This is rarely the case, but triggers with the Bluetooth
controller in code like this:

```
 #if defined(CONFIG_BT_PERIPHERAL)
        if (!lll->is_hdcd)
 #endif /* CONFIG_BT_PERIPHERAL */
        {
```

```
        } else
 #endif /* CONFIG_BT_CTLR_PRIVACY */
        {

```

```
 #if defined(CONFIG_BT_CTLR_DF_ADV_CTE_TX)
        if (lll->cte_started) {
                radio_switch_complete(phy_s, 0, phy_s, 0);
        } else
 #endif /* CONFIG_BT_CTLR_DF_ADV_CTE_TX */
        {
```

```
 #ifdef DUAL_BANK
        while ((FLASH_STM32_REGS(dev)->SR1 & FLASH_SR_QW) ||
               (FLASH_STM32_REGS(dev)->SR2 & FLASH_SR_QW))
 #else
        while (FLASH_STM32_REGS(dev)->SR1 & FLASH_SR_QW)
 #endif
        {
```

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>
This commit is contained in:
Carles Cufi 2024-12-26 16:45:15 +01:00 • committed by Benjamin Cabé
commit 3c420a4828
3 changed files with 32 additions and 60 deletions
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1
.checkpatch.conf
View file

@ -5,7 +5,6 @@
--min-conf-desc-length=1
--typedefsfile=scripts/checkpatch/typedefsfile
--ignore BRACES
--ignore PRINTK_WITHOUT_KERN_LEVEL
--ignore SPLIT_STRING
--ignore VOLATILE

3
doc/contribute/guidelines.rst
View file

@ -545,8 +545,7 @@ exceptions:
* The line length is 100 columns or fewer. In the documentation, longer lines
for URL references are an allowed exception.
* Add braces to every ``if``, ``else``, ``do``, ``while``, ``for`` and
``switch`` body, even for single-line code blocks. Use the ``--ignore BRACES``
flag to make *checkpatch* stop complaining.
``switch`` body, even for single-line code blocks.
* Use spaces instead of tabs to align comments after declarations, as needed.
* Use C89-style single line comments, ``/* */``. The C99-style single line
comment, ``//``, is not allowed.

88
scripts/checkpatch.pl
View file

@ -5497,8 +5497,9 @@ sub process {
my ($whitespace) = ($cond =~ /^((?:\s*\n[+-])*\s*)/s);
my $offset = statement_rawlines($whitespace) - 1;
$allowed[$allow] = 0;
#print "COND<$cond> whitespace<$whitespace> offset<$offset>\n";
# always allow braces (i.e. require them)
$allowed[$allow] = 1;
#print "COND<$cond> block<$block> whitespace<$whitespace> offset<$offset>\n";
# We have looked at and allowed this specific line.
$suppress_ifbraces{$ln + $offset} = 1;
@ -5507,46 +5508,37 @@ sub process {
$ln += statement_rawlines($block) - 1;
substr($block, 0, length($cond), '');
#print "COND<$cond> block<$block>\n";
# Remove any 0x1C characters. The script replaces
# comments /* */ with those.
$block =~ tr/\x1C//d;
$seen++ if ($block =~ /^\s*{/);
#print "cond<$cond> block<$block> allowed<$allowed[$allow]>\n";
if (statement_lines($cond) > 1) {
#print "APW: ALLOWED: cond<$cond>\n";
$allowed[$allow] = 1;
}
if ($block =~/\b(?:if|for|while)\b/) {
#print "APW: ALLOWED: block<$block>\n";
$allowed[$allow] = 1;
}
if (statement_block_size($block) > 1) {
#print "APW: ALLOWED: lines block<$block>\n";
$allowed[$allow] = 1;
}
$allow++;
}
if ($seen) {
my $sum_allowed = 0;
foreach (@allowed) {
$sum_allowed += $_;
}
if ($sum_allowed == 0) {
WARN("BRACES",
"braces {} are not necessary for any arm of this statement\n" . $herectx);
} elsif ($sum_allowed != $allow &&
$seen != $allow) {
CHK("BRACES",
"braces {} should be used on all arms of this statement\n" . $herectx);
}
my $sum_allowed = 0;
foreach (@allowed) {
$sum_allowed += $_;
}
#print "sum_allowed<$sum_allowed> seen<$seen> allow<$allow>\n";
if ($sum_allowed == 0) {
WARN("BRACES",
"braces {} are not necessary for any arm of this statement\n" . $herectx);
} elsif ($seen != $allow) {
WARN("BRACES",
"braces {} must be used on all arms of this statement\n" . $herectx);
}
}
}
if (!defined $suppress_ifbraces{$linenr - 1} &&
$line =~ /\b(if|while|for|else)\b/) {
my $allowed = 0;
# Check the pre-context.
if (substr($line, 0, $-[0]) =~ /(\}\s*)$/) {
# Check the pre-context for:
# '#': #if
# '}': } while()
if (substr($line, 0, $-[0]) =~ /([\#\}]\s*)$/) {
#print "APW: ALLOWED: pre<$1>\n";
$allowed = 1;
}
@ -5556,39 +5548,21 @@ sub process {
# Check the condition.
my ($cond, $block) = @{$chunks[0]};
#print "CHECKING<$linenr> cond<$cond> block<$block>\n";
#print "level $level CHECKING<$linenr> cond<$cond> block<$block>\n";
if (defined $cond) {
substr($block, 0, length($cond), '');
}
if (statement_lines($cond) > 1) {
#print "APW: ALLOWED: cond<$cond>\n";
$allowed = 1;
}
if ($block =~/\b(?:if|for|while)\b/) {
#print "APW: ALLOWED: block<$block>\n";
$allowed = 1;
}
if (statement_block_size($block) > 1) {
#print "APW: ALLOWED: lines block<$block>\n";
$allowed = 1;
}
# Check the post-context.
if (defined $chunks[1]) {
my ($cond, $block) = @{$chunks[1]};
if (defined $cond) {
substr($block, 0, length($cond), '');
}
if ($block =~ /^\s*\{/) {
#print "APW: ALLOWED: chunk-1 block<$block>\n";
$allowed = 1;
}
}
if ($level == 0 && $block =~ /^\s*\{/ && !$allowed) {
# Remove any 0x1C characters. The script replaces
# comments /* */ with those.
$block =~ tr/\x1C//d;
#print sprintf '%v02X', $block;
#print "\n";
if ($level == 0 && $block !~ /^\s*\{/ && !$allowed) {
my $cnt = statement_rawlines($block);
my $herectx = get_stat_here($linenr, $cnt, $here);
WARN("BRACES",
"braces {} are not necessary for single statement blocks\n" . $herectx);
"braces {} are required around if/while/for/else\n" . $herectx);
}
}