[U-Boot] [PATCH] SPDX: document dual license notation

[Stephen Warren]

On 10/08/2013 01:53 PM, Wolfgang Denk wrote:
> In [1] we discussed how we should deal with dual (or, more generally,
> multiple) licensed files.  Add this to  Licenses/README  so it's
> properly documented.
> 
> [1] http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/166518
> 
> Signed-off-by: Wolfgang Denk <wd at denx.de>
> ---
>  Licenses/README | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/Licenses/README b/Licenses/README
> index 9f61192..6dd7d5b 100644
> --- a/Licenses/README
> +++ b/Licenses/README
> @@ -37,6 +37,18 @@ replaced by a single line:
>  
>  	SPDX-License-Identifier:	GPL-2.0+
>  
> +Ideally, the license terms of all files in the source tree should be
> +defined by such License Identifiers; in no case a file can contain
> +more than one such License Identifier.

I assume "one such License Identifier" here is intended to mean: a
source line prefixed with the words "SPDX-License-Identifier:". However,
to me "one such License Identifier" would actually refer to the
"GPL-2.0+" part of the line, since that's what actually identifies the
license. The other text simply introduces a list of license identifiers.
That would then conflict with the rest of the patch that goes on to
explicitly state that multiple licenses are allowed.

In other words, I think that text can be confusing. I think you need to
add "line", "list" or "set" to the end of the sentence to make it
unambiguous.

> +If a "SPDX-License-Identifier:" line references more than one Unique
> +License Identifier, then this means that the respective file can be
> +used under the terms of either of these licenses, i. e. with
> +
> +	SPDX-License-Identifier:	GPL-2.0+	BSD-3-Clause
> +
> +you can chose between GPL-2.0+ and BSD-3-Clause licensing.