[PATCH v4] devtools: add .clang-format file

[Bruce Richardson]

On Wed, May 15, 2024 at 11:28:33AM +0300, Abdullah Ömer Yamaç wrote:
>    I want to update you.
>    On Mon, May 13, 2024 at 4:08 PM Ferruh Yigit <[1]ferruh.yigit at amd.com>
>    wrote:
> 
>      On 5/8/2024 10:19 PM, Abdullah Ömer Yamaç wrote:
>      > clang-format is a tool to format C/C++/Objective-C code. It can be
>      used
>      > to reformat code to match a given coding style, or to ensure that
>      code
>      > adheres to a specific coding style. It helps to maintain a
>      consistent
>      > coding style across the DPDK codebase.
>      >
>      > .clang-format file overrides the default style options provided by
>      > clang-format and large set of IDEs and text editors support it.
>      >
>      > Signed-off-by: Abdullah Ömer Yamaç <[2]aomeryamac at gmail.com>
>      >
>      Hi Omer,
>      I tried on ethdev.c (clang-format -i ./lib/ethdev/rte_ethdev.c), I
>      will
>      highlight a few issues below (not all of them), I hope it is OK to
>      continue step by step, fixing these issues.
>      1. clang format failed for following options, not sure why, am I
>      using a
>      wrong version:
>      LineEnding: LF
>      InsertNewlineAtEOF: true
>      I commented them out to continue the test.
>      And for 'ColumnLimit', I prefer default 80 with the flexibility to
>      go
>      100 when makes sense, so I will got with 'ColumnLimit: 80'; but I
>      don't
>      want to start this discussion.
> 
>    In the .editorconfig file, 100 is stated as a max_line_length. That's
>    why I prefer 100.
> 

+1 for keeping as 100

>      2. Double tab indentation vs parenthesis align
>               if (iter->bus != NULL &&
>       -                       /* not in middle of rte_eth_dev iteration,
>      */
>       -                       iter->class_device == NULL) {
>       +           /* not in middle of rte_eth_dev iteration, */
>       +           iter->class_device == NULL) {
>      DPDK coding guide suggests double tab, but also accepts alignment by
>      spaces. But as far as I can see most of code has double tab.
>      Majority of the diff caused because of this rule.
> 
>    Still, some discussions are going on
> 

This is one where I don't think we will were reach a consensus, and even if
we did, it would mean massive churn to DPDK. Can we have clang-format NOT
adjust line-continuations in a file?

Thanks,
/Bruce