[libcamera-devel] [PATCH 2/2] utils: checkstyle.py: Support single line hunks

[Kieran Bingham]

Hi Laurent,

On 07/01/2020 15:58, Laurent Pinchart wrote:
> Hi Kieran,
> 
> Thank you for the patch.
> 
> On Tue, Jan 07, 2020 at 03:44:41PM +0000, Kieran Bingham wrote:
>> The checkstyle script expects hunks to be declared with a start line and
>> line count, however the unified diff format [0] declares that a single
>> line hunk will only have the start line:
>>
>>> If a hunk contains just one line, only its start line number appears.
>>> Otherwise its line numbers look like ‘start,count’. An empty hunk is
>>> considered to start at the line that follows the hunk.
>>
>> [0] https://www.gnu.org/software/diffutils/manual/html_node/Detailed-Unified.html#Detailed-Unified
>>
>> Attempting to parse a single line hunk results in the following error:
>>
>>   File "./utils/checkstyle.py", line 110, in __init__
>>     raise RuntimeError("Malformed diff hunk header '%s'" % line)
>>   RuntimeError: Malformed diff hunk header '@@ -1 +1,2 @@
>>
>> The DiffHunk class only makes use of the start line, and does not
>> utilise the line count, thus update the regex to make the unused
>> groups optional, along with its comma separator.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>> ---
>>  utils/checkstyle.py | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/utils/checkstyle.py b/utils/checkstyle.py
>> index 41cd3371e81e..ab3b977358c7 100755
>> --- a/utils/checkstyle.py
>> +++ b/utils/checkstyle.py
>> @@ -102,7 +102,7 @@ class DiffHunkSide(object):
>>  
>>  
>>  class DiffHunk(object):
>> -    diff_header_regex = re.compile(r'@@ -([0-9]+),([0-9]+) \+([0-9]+),([0-9]+) @@')
>> +    diff_header_regex = re.compile(r'@@ -([0-9]+)(,[0-9]+)? \+([0-9]+)(,?[0-9]+)? @@')
> 
> How about
> 
>     diff_header_regex = re.compile(r'@@ -([0-9]+),?([0-9]+)? \+([0-9]+),?([0-9]+)? @@')
> 
> so that the count will be correctly captured, in case we need it later ?

That could be better, but it doesn't make the ',' invalid in the case of
 @@ -1, +1,12 @@

That likely shouldn't happen, and perhaps isn't an issue. Are you happy
for the ',' to be allowed when no digits follow?

I don't think I can come up with either a reason for how this string
might end up occurring, or how it would be a problem if we parsed it as
such.. (until we make use of the hunk length at least).

If you're happy, I'll update the string (and commit message) and push.
--
Kieran


> 
>>      def __init__(self, line):
>>          match = DiffHunk.diff_header_regex.match(line)
> 

-- 
Regards
--
Kieran