Re: [PATCH v3 4/4] Remove extra copies of licenses and license headers

[Julien Grall <julien@xxxxxxx>]

Hi Stefano,

On 08/10/2022 01:15, Stefano Stabellini wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxx>
>
> Remove the extra copy of the GPL license and license copyright headers
> from CONTRIBUTING and the top-level COPYING.
>
> Mention of the LICENSES/ directory and also mention the SPDX tag.
>
> SPDX support is still in progress and COPYING files in subdirectories
> still need to be updated.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
> ---
> Patch new in v3
> ---
>   CONTRIBUTING | 150 ++--------------------
>   COPYING      | 351 +--------------------------------------------------
>   2 files changed, 17 insertions(+), 484 deletions(-)
>
> diff --git a/CONTRIBUTING b/CONTRIBUTING
> index 6ec146baf0..7b6b03fb96 100644
> --- a/CONTRIBUTING
> +++ b/CONTRIBUTING
> @@ -19,10 +19,6 @@ Most notably:
>    - tools/xl           : LGPL v2.1
>    - xen/include/public : MIT license
>   
> -The COMMON COPYRIGHT NOTICES section of this document contains
> -sample copyright notices for the most common licenses used within
> -this repository.
> -
How about replacing this section with something like:

" See LICENSES/ for a list of licenses and SPDX tags currently used."

>   When creating new components, new files, or importing code please follow
>   the conventions outlined below. As a general rule, whenever code using a
>   license other than GPLv2 is introduced, attention must be drawn to the
> @@ -32,20 +28,22 @@ deviation. Any new code must be GPLv2 compatible.
>   New components
>   --------------
>   
> -When creating new components and directories that contain a
> -significant amount of files that are licensed under licenses other
> -than GPLv2 or the license specified in the COPYING file, please
> -create a new COPYING file in that directory containing a copy of the
> -license text and a rationale for using a different license. This helps
> -ensure that the license of this new component/directory is maintained
> -consistently with the original intention.
> +When creating new components and directories that contain a significant
> +amount of files that are licensed under licenses other than GPLv2,
> +please create a new COPYING file in that directory with the rationale
> +for using a different license. This helps ensure that the license of
> +this new component/directory is maintained consistently with the
> +original intention.
I don't understand why the wording "or the license specified in the 
COPYING file" is dropped. To me, the sentence was indicating that it is 
not necessary to create a COPYING file in every sub-directory if the 
license is not GPLv2 and it matches the license of a parent directory.
Do you plan to remove COPYING completely?

>   
>   New files
>   ---------
>   
> -If specific files that differ from the license in a directory are introduced,
This is fine to drop but ...

> -exceptions should be highlighted and discussed in the commit message or cover
> -letter introducing the file.
... I think this should be kept because we want to have justification 
why the license of a file doesn't match the license of the directory.
> +New files should start with a single-line SPDX comment to express the
> +license. The following comment and license are recommended:
Someone reading this may think that a new file in libxl wants to be 
GPLv2. So I would add in parentheses that the license may be different 
in some directory.
Similarly, I think this should be stronger than recommended. The SPDX 
should be a *must* and for the license there are effectively little 
leeway in which one we could use for existing components.
So how about:

"For instance, if the file is GPLv2, the comment would look like:

/* SPDX-License-Identifier... */

The recommended license of a directory will depend on the COPYING file. 
If the new file is using a different license, this should be highlighted 
and discussed in the commit message or cover letter introducing the file.
"

Cheers,

--
Julien Grall