Add symbol tags as proposed for LSP specification (e.g. visibility tags, static, abstract, etc.)

[travkin79]

Adds new symbol tags as proposed in my PR on the LSP specification, for example, adding private, package, protected, and public visibility tags as well as tags like static, final, abstract, read-only, nullable and non-null. Our motivation comes from our wish to add visibility and other symbol details to the outline view (see discussion https://github.com/eclipse/lsp4e/discussions/977), but maybe also to the call hierarchy and to the type hierarchy or to other related features / LSP operations.

The PR on the LSP specification requires at least one implementation in a language server and / or a client. We plan to finish a [first language server implementation in clangd](https://github.com/microsoft/language-server-protocol/pull/2003 and https://github.com/llvm/llvm-project/pull/113669) and a first client implementation in LSP4J, LSP4E, and CDT LSP (which is using clangd).

See https://github.com/microsoft/language-server-protocol/pull/2003 and https://github.com/llvm/llvm-project/pull/113669 and https://github.com/eclipse-lsp4e/lsp4e/pull/1149

[jonahgraham]

@travkin79 your use case is compelling. AFAIK LSP4J hasn't been the first implementation for an LSP feature before. LSP4J has had pre-released features though. It sounds like we have a bit of a chicken-and-egg situation here, and I don't want LSP4J to be what prevents moving us forward.

For pre-release we marked all elements that were not in the official spec with @Beta (com.google.common.annotations.Beta). Lets do that here too and then we can move towards a release with this change in it.

Nothing in the current HEAD has @Beta - but see an old example part of #133 if you want a reference: https://github.com/eclipse-lsp4j/lsp4j/blob/74e880416b16b2a9acf1dbd8a6871de47ef24e7e/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend#L1938

Having the @Beta means we can change around those items easier without as much consideration for API consumers of LSP4J.

[travkin79]

Hi @jonahgraham, Thank you for the hint to the @Beta annotations. I think, I've seen them already somewhere. I'll add them and I think, they are very helpful for explicitly documenting API that is likely to change in near future.

Concerning the chicken-and-egg situation: I think, for getting my LSP specification proposal accepted, we need the following steps in the following order.

1. finish the first clangd language server implementation using the new symbol tags (https://github.com/llvm/llvm-project/pull/113669)
2. finish first language server client implementation that uses the new symbol tags i. Extend LSP4J to support the new symbol tags (#856) ii. Extend LSP4E to use the new symbol tags, e.g. in the outline view (https://github.com/eclipse-lsp4e/lsp4e/pull/1149 and https://github.com/eclipse-lsp4e/lsp4e/discussions/977)
3. Hope for the LSP specification PR to be accepted (https://github.com/microsoft/language-server-protocol/pull/2003)

[travkin79]

Hi @jonahgraham, It took some time, but now, we can go on with this PR and related PRs, since a first language server implementation for this change is now finished (implemented in clangd and the PR is ready to be merged). Could you please take a look at this PR?

I've used the @Beta annotations for the new symbol tags that are proposed to the LSP specification, but are not accepted yet. I've seen the @ProtocolDraft. Could that be a replacement for the @Beta annotations?

Reminder: For the LSP specification proposal to be accepted, we have to provide an exemplary implementation in one language server and one client. We chose clangd, LSP4J, LSP4E (and CDT LSP) for that.

Related work:

• LSP change proposal with new symbol tags (PR): https://github.com/microsoft/language-server-protocol/pull/2003
• First LS implementation, here für C/C++ in clangd (PR): https://github.com/llvm/llvm-project/pull/167536
• Client-side implementation in LSP4E (PR): https://github.com/eclipse-lsp4e/lsp4e/pull/1149

[github-actions[bot]]

Test Results

  500 files  ±0    500 suites  ±0   35s ⏱️ -3s   359 tests ±0    359 ✅ ±0  0 💤 ±0  0 ❌ ±0  4 052 runs  ±0  4 052 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit d66fd192. ± Comparison against base commit b5a8adfa.

:recycle: This comment has been updated with latest results.

[jonahgraham]

@travkin79 This has been merged and is available in maven snapshots + nightly builds, the p2 repo is:

https://download.eclipse.org/lsp4j/builds/main/ (the heavy caching of download.e.o may mean this takes a little while to consistently show the updated version)

You should be able to update this line of your LSP4E PR to point to the above to get it to build. You'll also have to update the version ranges in the various MANIFEST.MFs:

As for the release date of 1.0.0, it is not set yet, but follow https://github.com/eclipse-lsp4j/lsp4j/issues/871 and weigh in on your desires and needs.

[travkin79]

Hi @jonahgraham, Thank you very much for the review and your helpful hints. I'll update my LSP4E PR soon.