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

[Laurent Pinchart]

Hi Kieran,

On Tue, Jan 07, 2020 at 04:04:00PM +0000, Kieran Bingham wrote:
> On 07/01/2020 15:58, Laurent Pinchart wrote:
> > 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.

It's a good point. I'm happy either way, but if we include the ',' in
the group, does the last group need to have a '?' after the ',' ? i.e.
shouldn't it be

    diff_header_regex = re.compile(r'@@ -([0-9]+)(,[0-9]+)? \+([0-9]+)(,[0-9]+)? @@')

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

-- 
Regards,

Laurent Pinchart