VS Code initially added the PublishDiagnosticsCapabilities#tagSupport as boolean in the vscode-language-client implementation, but without adding it to the LSP spec. In LSP 3.15 it was finally speced out as being of type DiagnosticsTagSupport and the client implementation was adapted in version 6.0.0.
So all clients relying on vscode-language-client < 6.0.0 will fail to connect to a lsp4j server as it cannot parse their initialize request. Unfortunately, that includes the monaco-language-client, and thereby all extensions to Eclipse Theia. It's unlikely this can be fixed within the next weeks.
For the time being, I'd propose to change the type of PublishDiagnosticsCapabilities#tagSupport to Either<Boolean, DiagnosticsTagSupport>.
VS Code initially added the
PublishDiagnosticsCapabilities#tagSupportas boolean in thevscode-language-clientimplementation, but without adding it to the LSP spec. In LSP 3.15 it was finally speced out as being of typeDiagnosticsTagSupportand the client implementation was adapted in version 6.0.0.So all clients relying on
vscode-language-client< 6.0.0 will fail to connect to a lsp4j server as it cannot parse their initialize request. Unfortunately, that includes themonaco-language-client, and thereby all extensions to Eclipse Theia. It's unlikely this can be fixed within the next weeks.For the time being, I'd propose to change the type of
PublishDiagnosticsCapabilities#tagSupporttoEither<Boolean, DiagnosticsTagSupport>.