Re: Why these dot chars in scripts/checkpatch.pl?

Previous thread: Linux 2.4 usage statistics by Willy Tarreau on Monday, April 28, 2008 - 4:24 pm. (7 messages)

Next thread: 2.6.25-git12 sysfs panic by Badari Pulavarty on Monday, April 28, 2008 - 4:36 pm. (2 messages)
To: Andy Whitcroft <apw@...>
Cc: <linux-kernel@...>
Date: Monday, April 28, 2008 - 4:31 pm

Andy,

Perhaps I'm loosing my magic regex pixie dust, but the dot '.' char
in the pattern "/^.#" in the following lines looks wrong to me, as if
one were trying to match pre-processor directives that were set in by
one character:

The command:

grep '^[^#].*\/\^\.#' scripts/checkpatch.pl

displays:

if ($res =~ /^.#\s*include\s+\<(.*)\>/) {
} elsif ($res =~ /^.#\s*(?:error|warning)\s+(.*)\b/) {
if ($line =~ /(.*)\b((?:if|while|for|switch)\s*\(|do\b|else\b)/ && $line !~ /^.#/) {
if ($line =~ /^.#\s*if\s+0\b/) {
if ($line =~ /^.#\s*(ifdef|ifndef|elif)\s\s+/) {
$line !~ /^.#\s*if\b.*\bNR_CPUS\b/ &&
$line !~ /^.#\s*define\b.*\bNR_CPUS\b/ &&

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.940.382.4214
--

To: Paul Jackson <pj@...>
Cc: <linux-kernel@...>
Date: Monday, April 28, 2008 - 7:02 pm

This is because we always are dealing with diff lines, not real lines.
So there is always a ' ', '+', or '-' in character 0 of the line (within
a diff hunk). In some tests we may be looking at either context ' '
or new lines '+' and so its handy to use '.' over '[ \+]', and I have

-apw
--

To: Paul Jackson <pj@...>
Cc: Andy Whitcroft <apw@...>, <linux-kernel@...>
Date: Monday, April 28, 2008 - 4:47 pm

Perhaps it is because checkpatch.pl is supposed to check *patches*,
which are typically indented by one character (+- )?

Rogan

--

To: Rogan Dawes <lists@...>
Cc: Paul Jackson <pj@...>, Andy Whitcroft <apw@...>, <linux-kernel@...>
Date: Monday, April 28, 2008 - 6:10 pm

Even so, the regexes are not entirely accurate.
Patch below.

===
commit e08a94e334d67ac5f2437c8aba4c6ffbb058d7db
Author: Jan Engelhardt <jengelh@medozas.de>
Date: Tue Apr 29 00:06:42 2008 +0200

checkpatch: fix recognition of preprocessor directives

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 58a9494..22df611 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -355,12 +355,12 @@ sub sanitise_line {
}

# The pathname on a #include may be surrounded by '<' and '>'.
- if ($res =~ /^.#\s*include\s+\<(.*)\>/) {
+ if ($res =~ /^.\s*#\s*include\s+\<(.*)\>/) {
my $clean = 'X' x length($1);
$res =~ s@\<.*\>@<$clean>@;

# The whole of a #error is a string.
- } elsif ($res =~ /^.#\s*(?:error|warning)\s+(.*)\b/) {
+ } elsif ($res =~ /^.\s*#\s*(?:error|warning)\s+(.*)\b/) {
my $clean = 'X' x length($1);
$res =~ s@(#\s*(?:error|warning)\s+).*@$1$clean@;
}
@@ -1194,7 +1194,7 @@ sub process {

# if/while/etc brace do not go on next line, unless defining a do while loop,
# or if that brace on the next line is for something else
- if ($line =~ /(.*)\b((?:if|while|for|switch)\s*\(|do\b|else\b)/ && $line !~ /^.#/) {
+ if ($line =~ /(.*)\b((?:if|while|for|switch)\s*\(|do\b|else\b)/ && $line !~ /^.\s*#/) {
my $pre_ctx = "$1$2";

my ($level, @ctx) = ctx_statement_level($linenr, $realcnt, 0);
@@ -1877,7 +1877,7 @@ sub process {
}

# warn about #if 0
- if ($line =~ /^.#\s*if\s+0\b/) {
+ if ($line =~ /^.\s*#\s*if\s+0\b/) {
CHK("if this code is redundant consider removing it\n" .
$herecurr);
}
@@ -1891,14 +1891,14 @@ sub process {
}

# warn about #ifdefs in C files
-# if ($line =~ /^.#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {
+# if ($line =~ /^.\s*#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {
# print "#ifdef in C files should be avoided\n";
# print "$here...

To: Jan Engelhardt <jengelh@...>
Cc: Rogan Dawes <lists@...>, Paul Jackson <pj@...>, <linux-kernel@...>
Date: Monday, April 28, 2008 - 7:06 pm

Yeah I was under the missaprehension that whitespace was allowed after
the # but not before. That seems to be flawed. Thanks for the patch.

"Preprocessing directives are lines in your program that start with `#'.
--

To: Andy Whitcroft <apw@...>
Cc: Paul Jackson <pj@...>, Rogan Dawes <lists@...>, Jan Engelhardt <jengelh@...>, <linux-kernel@...>
Date: Tuesday, April 29, 2008 - 5:51 am

It is true for K&R C (so with -traditional cpp mode), but indeed
false for ISO C.

Segher

--

To: Rogan Dawes <lists@...>
Cc: <apw@...>, <linux-kernel@...>
Date: Monday, April 28, 2008 - 4:51 pm

You're a genius. It's an honor to be of the same species.

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.940.382.4214
--

Previous thread: Linux 2.4 usage statistics by Willy Tarreau on Monday, April 28, 2008 - 4:24 pm. (7 messages)

Next thread: 2.6.25-git12 sysfs panic by Badari Pulavarty on Monday, April 28, 2008 - 4:36 pm. (2 messages)