Clarify license and redistributability of bundled WinSDK headers

[mstorsjo]

The repo contains a toplevel file LICENSE, indicating that the files are covered by the MIT license (allowing redistribution etc).

The repo also contains a number of headers from WinSDK (under generation/WinSDK/RecompiledIdlHeaders). The headers in WinSDK generally aren't redistributable (the WinSDK license doesn't allow redistribution of anything else than specific redistributables). The files here also contain such a license header that don't seem to imply that it's intended to be freely redistributable under the MIT license, e.g. looking at um/winnt.h:

/*++ BUILD Version: 0072     Increment this if a change has global effects
    
Copyright (c) Microsoft Corporation. All rights reserved.     

(Which explicitly says All rights reserved. and nothing about the file being redistributable under any OSS license).

Also as noted in #387, the NuGet package form links to the WinSDK license (which doesn't permit redistribution).

Thus, is it possible to make it clearer that all the included files, including the WinSDK headers, now are redistributable according to the MIT license (which seems to be the intent?), in contrast to when receiving those headers from a regular WinSDK installation?

[danny-laa]

FYI, MIT License includes an All rights reserved. clause too.

[mstorsjo]

FYI, MIT License includes an All rights reserved. clause too.

Hmm, at least my reading of it, at https://opensource.org/licenses/MIT, doesn't contain that phrase in the license itself. But anyway, even if the phrase is used... If it's directly followed by the text granting specific permissions, it's a different thing that when the clause stands on its own with no further grants or even references to other license files.

[riverar]

Mike Battista (@mikebattista) Bubbling this up as it has become quite popular.

[mikebattista]

We haven't changed the license of the original SDK headers. The license in this repo is for the metadata and tooling around it.

[g2p]

This repo contains foundational metadata for various language bindings. The licence files here are clear enough about the licence for the tools, but the metadata is derived from non redistributable headers, and it is not obvious that you relicense it.

[emidoots]

Mike Battista (@mikebattista)

We haven't changed the license of the original SDK headers.

Is this to be interpreted as "the files under generation/WinSDK/RecompiledIdlHeaders in this repository are not open source / MIT licensed"?

[emidoots]

Mike Battista (@mikebattista) Rafael Rivera (@riverar) just curious if you could clarify the above still

[mikebattista]

The headers there have their own clauses that take precedence. We haven't changed the licenses of those headers to the MIT license.

[ChrisDenton]

So win32metadata/generation/WinSDK/RecompiledIdlHeaders/ are not open source?

Are Windows.Win32.winmd and Windows.Win32.Interop.dll MIT licensed, despite the fact they are derived from headers with a restrictive license?

[riverar]

Are Windows.Win32.winmd and Windows.Win32.Interop.dll MIT licensed, despite the fact they are derived from headers with a restrictive license?

Microsoft owns its own headers so there's no issue here.

General guidance here is:

• Metadata assemblies and tooling are MIT, feel free to use!
• Yes, the NuGet is licensed weirdly (Windows SDK license). You can get the same files at https://github.com/microsoft/win32metadata/tree/main/scripts/BaselineWinmd to workaround that until it's changed.
• All the tooling dependencies (e.g. headers, idl, sdk bits, etc.) are licensed separately, don't use them / forget they exist (waves hand over head)

I don't think we're going to get anything more concrete than that without legal involvement (and frankly they're not going to bother here), so closing this issue for now.

[ChrisDenton]

You can get the same files at https://github.com/microsoft/win32metadata/tree/main/scripts/BaselineWinmd to workaround that until it's changed.

It would be nice if this was made explicit somewhere so people know it's safe to create works derived from them even though they are themselves derived from sources that have a restrictive license. This hasn't been clear to people, IMHO.

Actually, it'd be great if your "general guidance" were in the readme or a FAQ to avoid this confusion in the future.