Fix: Added notice for third party licenses

[hishitetsu]

Since Files contains third-party software that is not under the MIT license, it should be clearly stated that a different license applies to them.
I also think it should be added to third party licenses display on the app's settings screen, but first I submit a pull request for the license file.

Edit:
Now LICENSE is unchanged. I have added NOTICE.md to clarify third-party software licenses.

[0x5bfa]

This is invalid Licensing. Please refer to GPL license. If Files has ANY code licensed under the GPL, whole code must be licensed under the GPL. And so, we have to remove code licensed under the GPL(especially FilesLauncher).

This kind declaration is only valid for 'Attribution' such as CC license.

[hishitetsu]

If Files has ANY code licensed under the GPL, whole code must be licensed under the GPL.

This is true if Files links to GPL codes. However, the GPL code is only used for FilesLauncher. Files itself uses no GPL codes, just includes FilesLancher.exe.
So I don't think it is a clear violation of the GPL.

In summary, I think Files can be described as a collection of the following four pieces of software.

• LGPL licensed 7z.dll
• LGPL licensed SevenZipSharp
• GPL licensed FilesLauncher.exe
• All remaining codes which is MIT licensed and can be copyrighted

[yaira2]

FilesLauncher

Most of FilesLauncher is custom built by @gave92, we should look into rewriting the GPL parts.

[hishitetsu]

I have made a few changes. Other than FilesLauncher, this repository also contains LGPL binaries, so it would be bad to simply show only the MIT license.

[0x5bfa]

Let me be clear about Inability to coexist

Excerpt from GPL v3, Section 5, Paragraph c:

  5. Conveying Modified Source Versions.

    c) You must license the entire work, as a whole, under this
    License to anyone who comes into possession of a copy.  This
    License will therefore apply, along with any applicable section 7
    additional terms, to the whole of the work, and all its parts,
    regardless of how they are packaged.  This License gives no
    permission to license the work in any other way, but it does not
    invalidate such permission if you have separately received it.

[hishitetsu]

I think "the entire work" here can be limited to FileLauncher since it is an independent program.
This would be the case shown in the following FAQ.
https://www.gnu.org/licenses/gpl-faq.html.en#GPLCompatInstaller

[0x5bfa]

A lot of articles says 'you must have entire work be under the GPL'. Some of, don't have to. Quite confused...

should write those statements in NOTICE.md

https://github.com/microsoft/terminal/blob/main/NOTICE.md

[hishitetsu]

A lot of articles says 'you must have entire work be under the GPL'.

If so, linux distributions would have to distribute all software under the GPL.
It depends on how we view this FAQ. I think they can be considered two separate programs, not one program with two parts.
https://www.gnu.org/licenses/gpl-faq.html.en#MereAggregation

[hishitetsu]

should write those statements in NOTICE.md

This is a good idea. Once we have a policy in place, I will add NOTICE.md instead of updating LICENSE.

[0x5bfa]

I finally found that MIT and GPL have compatibility and can be coexisted.
I'm wanna talk about that it is ok if we can wrap source codes including GPL License with MIT License in the first place. I think we cannot, so anyway we probably have to remove FilesLauncher.

[hishitetsu]

No. So, ideally, it would be better to move the GPLed code to a separate repository. But It would be okay to just specify which code is MIT-licensed and which is GPL-licensed.

[0x5bfa]

Where do you think we state that? LICENSE file cannot be changed cuz it's template. We probably have to add two-line-license-acknowledgement to all of source code like Microsoft's OSS?

Copyright (c) 2023 Files
Licensed under the MIT License. See the LICENSE file.

[0x5bfa]

which file was the one with GPL code? Are we even using it?

FilesLauncher. One reference in Files.App

Files/src/Files.App/ViewModels/SettingsViewModels/AdvancedViewModel.cs

Lines 253 to 259 in 25deb56

	private bool DetectIsSetAsDefaultFileManager()
	{
	using var subkey = Registry.ClassesRoot.OpenSubKey(@"Folder\shell\open\command");
	var command = (string?)subkey?.GetValue(string.Empty);
	return !string.IsNullOrEmpty(command) && command.Contains("FilesLauncher.exe");
	}

[hishitetsu]

FilesLauncher is used to replace File Explorer. It was introduced in #8684.

[0x5bfa]

The files which have a statement:

// Copyright (C) Explorer++ Project
// SPDX-License-Identifier: GPL-3.0-only
// See LICENSE in the top level directory

There's no license that include this license, though.

• DocumentServiceProvider.cpp
• DocumentServiceProvider.h
• ServiceProviderBase.cpp
• ServiceProviderBase.h
• ShellView.cpp
• ShellView.h
• WebBrowserApp.cpp
• WebBrowserApp.h

[hishitetsu]

We could revert #8684, but that would bring back the problem that was solved by #8684.

[0x5bfa]

We cannot revert. Only we can do is to rewrite/remove those codes in C# or C++. @gave92 created those files so we may ask him if those codes can be replaced/removed with our own C# or C++.

[0x5bfa]

We should open an issue. (Thank you for bringing this discussion)

[yaira2]

The files which have a statement:

// Copyright (C) Explorer++ Project
// SPDX-License-Identifier: GPL-3.0-only
// See LICENSE in the top level directory

There's no license that include this license, though.

• DocumentServiceProvider.cpp
• DocumentServiceProvider.h
• ServiceProviderBase.cpp
• ServiceProviderBase.h
• ShellView.cpp
• ShellView.h
• WebBrowserApp.cpp
• WebBrowserApp.h

I don't believe any of these are actively being used for setting the default file manager, these are for the open file picker which is still a very early work in progress. I think they can be safely removed.

[0x5bfa]

@yaira2 Can I work on?

[0x5bfa]

@hishitetsu My suggestion

• Revert all changes in LICENSE.
• Add NOTICE.md following format

---

# THIRT PARTY NOTICE and ACKNOWLEDGMENTS

**Note: DO NOT localize.**

## 7Zip

**Source code:** https://example.com

### License

\```
\```

THIRT PARTY NOTICE and ACKNOWLEDGMENTS

Note: DO NOT localize.

7Zip

Source code: https://example.com

License

[hishitetsu]

Yes, I will do so.
How about FilesLauncher? Should we include the mention of FilesLauncher in NOTICE.md?

[0x5bfa]

I don't think so. I will immediately delete them at least until this weekend.

[yaira2]

Add NOTICE.md following format

Is it enough to have this in the about page?

[0x5bfa]

It'd prefer both.

[hishitetsu]

For the licenses dialog, we could reuse some code from SecureFolderFS

Thanks for the information!
I mistakenly thought that SecureFolderFS also needs to be added to NOTICE. In any case, I have added a note about any mistakes in NOTICE.

[hishitetsu]

I intend to display NOTICE.md on the about page like this.

Though, we need to decide on the contents of NOTICE.md first.

[yaira2]

I believe @d2dyno1 is working on the one for the about page.

[hishitetsu]

Really? I worked on it too...

[yaira2]

The design @d2dyno1 is working on will have a separate page for licenses so I think we should wait for it. In the meantime, is this PR ready?

[hishitetsu]

In the meantime, is this PR ready?

Yes. Unless pointed out by others.

[0x5bfa]

LGTM.

[0x5bfa]

LGTM

[yaira2]

Thank you