Re: [PATCH 01/18] checkpatch: Fix checking of newlines in error messages

[Fabiano Rosas <farosas@suse.de>]

Peter Xu <peterx@redhat.com> writes:

> On Wed, Sep 02, 2026 at 07:15:29PM -0300, Fabiano Rosas wrote:
>> Using newlines in the g_test_message is fine. It automatically adds
>> the '#' required by the TAP protocol to the start of each line.
>
> IIUC we have such check not because TAP, but because all these functions
> will append one newline at the end, hence it's not needed.  IOW, if it
> applies to g_test_message(), I don't see why it doesn't apply to the rest.
> But maybe there're other reasons?
>
> To make it simpler, maybe we just call a few times g_test_message()?
>

Not sure I understand your point, Peter. I want to be able to print nice
messages in patch 9:

 g_test_message("expected vs. found:\n\n%s\n---\n%s:%s", str, t2[match], t2[match + 1]);

 # HMP output mismatch for entry at line 55:
 # expected vs. found:
 #
 # max-bandwidth: 10356305952768 bytes/hour
 # ---
 # max-bandwidth: 10356305952768 bytes/second

What would be the issue of having newlines here?

>> 
>> Relax the regex for this function, but still forbid a trailing newline
>> because it's added automatically and usually not what the user wants.
>> 
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> ---
>>  scripts/checkpatch.pl | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>> 
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
>> index 03f35e75012..fd4534b3a1e 100755
>> --- a/scripts/checkpatch.pl
>> +++ b/scripts/checkpatch.pl
>> @@ -3303,13 +3303,20 @@ sub process {
>>  					 info_vreport|
>>  					 error_report|
>>  					 warn_report|
>> -					 info_report|
>> -					 g_test_message}x;
>> +					 info_report}x;
>>  
>>  		if ($rawline =~ /\b(?:$qemu_error_funcs)\s*\(.*\".*\\n/) {
>>  			ERROR("Error messages should not contain newlines\n" . $herecurr);
>>  		}
>>  
>> +		# No newlines at the end
>> +		my $trail_newline_error_funcs = qr{g_test_message}x;
>> +
>> +		if ($rawline =~ /\b(?:$trail_newline_error_funcs)\(.*\".*\\n\"/) {
>> +		    ERROR("Error messages should not contain trailing " .
>> +			  "newlines\n" . $herecurr);
>> +		}
>> +
>>  		# Continue checking for error messages that contains newlines.
>>  		# This check handles cases where string literals are spread
>>  		# over multiple lines.
>> -- 
>> 2.53.0
>>