Hi Damjan,

Thanks for clarifying. When I saw that the initial patchset did not contain
the formatting changes, i thought checkstyle and fixstyle were involved in
adding them. Sorry for the confusion.

-Matt


On Thu, Apr 9, 2026 at 3:12 PM Damjan Marion via lists.fd.io <dmarion=
[email protected]> wrote:

>
> Those cosmetic changes are not happening because of clang-format
> misbehaving,
> they are happening by authors (or authors AI agent) choice.
> Those hunks can easily be reverted and verify job will pass.
> clang-format-diff operates only on lines modified and connected
> neighboring lines.
> I noticed that AI agents tend to mess with formatting.
> Many times so far I reverted this kind of changes before I submitted patch.
>
> Same will happen with code from “gnu indent” era which was touched in same
> way before 80->100 change.
>
> Regarding 80->100 change, even linux kernel folks decided to relax it in
> same way 4 years ago.
> I am also using vim and it works nicely. Code is more readable as there is
> less line-wraps.
>
> —
> Damjan
>
>
> On 09.04.2026., at 17:52, Matthew Smith via lists.fd.io <mgsmith=
> [email protected]> wrote:
>
> Hi,
>
> I was reviewing a patch (https://gerrit.fd.io/r/c/vpp/+/45456) and
> noticed that there were a lot of lines where no code was changed, but they
> were just reformatted to rearrange whitespace. It looked like the maximum
> width of a line was increased to 100. I then noticed that the .clang-format
> file had 'ColumnLimit: 100' added to it recently.
>
> If you look at https://gerrit.fd.io/r/c/vpp/+/45456 and compare Base to
> Patchset 1, the delta of src/vnet/sfdp/sfdp.c is +16 -2 and it's pretty
> easy to see what's being changed. Patchset 1 does not contain all of the
> formatting changes. If you compare Base to Patchset 5, the delta of
> src/vnet/sfdp/sfdp.c is +107 -112 and you have to scroll past a whole lot
> of formatting changes before you find the actual code changes.
>
> I presume that src/vnet/sfdp/sfdp.c was added before the change to
> .clang-format so it was formatted using a line width of 80 chars
> originally. Now that it's being changed, checkstyle is enforcing the new
> 100 char width on the file. I imagine that minor changes made to other
> files will be subject to the same issue - checkstyle will require a bunch
> of superfluous reformatting to increase line width to 100. This seems like
> it has the potential to make it a little harder to review changes that
> people submit since you will have to look very closely at which differences
> actually change behavior of the code and try to filter out a lot of noise
> resulting from formatting changes.
>
> Aside from the reformatting noise, I also usually find code formatted for
> 80 chars easier to read since I often am viewing source files in vim on a
> terminal window that defaults to 80 chars wide. Though I acknowledge that I
> might be in the minority in that regard nowadays.
>
> Does anyone else think this might be a problem?
>
> Thanks,
> -Matt
>
>
>
>
>
>
> 
>
>
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