[License] update license SPDX in all package.json, source file headers

[marcdumais-work]

What it does

update: following Wayne's feedback below, I have updated the description and content of this PR

This PR tweaks the secondary license SPDX short identifier, to use the most precise version that applies. It also restores the original text of secondary license, that was accidentally changed during the recent file split.

Making these changes should make our packages easier to deal-with, from an IP PoV, for adopters and extenders, by making our licenses easier to auto-detect.

For more details see the corresponding issue

Note: Since this PR changes our copyright headers and the stated license in various package.json files, I have created an IP ticket, for the Foundation IP Team to sign-off on these changes: ticket. We should probably wait (timeout: 3 weeks?) for feedback before merging.

The feedback was received and acted-upon. This PR updates the license headers to use the more precise, suggested SPDX:

Before:
SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0

After:
SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0

Fixes #12583

How to test

This PR makes changes to almost 2000 files. As such I have experienced slow load/update times, working in the GitHub PR diff view (Files Changed tab). It might be preferable to review the changes locally. I have split things in separate commits, so that important changes do not go unnoticed, among the mass of license header changes. Please consider looking at the PR commit-by-commit. We can squash into a single commit at the end, before merging.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[marcdumais-work]

This was not an intended change. When I try to change it back locally, the stars ** are automatically removed. I am guessing that using them is against some config we have somewhere. I think I would just leave out these stars, unless there are objections.

[vince-fugnitto]

The changes look good to me 👍

• the splitting looks correct
• the new header snippet works as intended
• the updated eslint rule correctly identifies errors with the header if missing, or mistyped

[marcdumais-work]

Note: I have a little doubt now, that the SPDX might have been correct. I checked on our EF project page, in the Legal Documents Generator page, and the license SPDX that we use is as proposed there. I am not sure if this might be an old way of referring to that license, but I did find several other matches, when searching online. I am not sure why the spdx.org page for this license does not match.

I have added a related comment on the IP ticket - let's see what the IP Team thinks

[waynebeaton]

The current form is actually more correct than the changes in this PR.

The GPL-2.0-with-classpath-exception form is deprecated by SPDX.

The documentation generator is correct. It should be EPL-2.0 OR GPL-2.0-only with Classpath-exception-2.0.

Note that this is different from what you're currently using. The GPL-2.0 form is also deprecated by SPDX.

FWIW, there are two choices for the GPL-2.0: GPL-2.0-only or GPL-2.0-or-later. The second form is, as the name suggests, for cases where you license something under the GPL-2.0 "or any later version" (you'll see that from time-to-time). I believe that GPL-2.0-only is correct for Eclipse Theia.

So... the SPDX-License-Identifier should be EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0.

Note that while changing GPL-2.0 to GPL-2.0-only will make the headers more correct, most SPDX parsers will still be able to make sense of GPL-2.0. That is, the EMO is supportive of this change but considers it low priority.

[marcdumais-work]

I believe that GPL-2.0-only is correct for Eclipse Theia.

Agreed.

The current form is actually more correct than the changes in this PR.

Note that while changing GPL-2.0 to GPL-2.0-only will make the headers more correct, most SPDX parsers will still be able to make sense of GPL-2.0. That is, the EMO is supportive of this change but considers it low priority.

Understood, thanks @waynebeaton!

[vince-fugnitto]

I re-affirm my previous review 👍

[marcdumais-work]

@msujew I wanted to mention that I tested the GitHub detection of our licenses, using my fork (the only consistent way I found was to merge to master and observe how it affected the detection). Doing so, I have confirmed that even with tweaked SPDX, the licenses were not detected correctly when I tried going-back to a single license file. So, I think your split of the single license file, into two files, was the correct move!

[marcdumais-work]

Thanks for the review @vince-fugnitto . I will squash the commits locally and tidy-up the commit message.

[marcdumais-work]

I have just rebased this PR locally to confirm that linting still passes (in case a PR had been merged in the meantime, that used the old SPDX in source header. So, there should be no surprises when we merge. It's possible that there are PRs under review that will need to update new headers - the safest will be to rebase on latest master once this one here is in.

[msujew]

Thank you for the work on this @marcdumais-work, looks good to me as well 👍