Code action request from problems view includes additional diagnostics

[suzmue]

Does this issue occur when all extensions are disabled?: No

• VS Code Version: 1.71.1
• OS Version: macOS Monterey version 12.6

Steps to Reproduce:

1. Have a project that has multiple diagnostics for the same range and where each diagnostic has a suggested fix.
2. Open the problems view and hover over one of the diagnostics to get the code actions for that diagnostic.

I would expect to see the code action just for that diagnostic, not all diagnostics in the same range. The LSP textDocument/codeAction request includes all of the diagnostics in that range as the context for the codeAction request, not just the selected one in the problems view.

For example, the two diagnostics below have the same line. Getting the quick fixes for one diagnostic, will send a request with both diagnostics included in the context:

Params: {"textDocument":{"uri":"file:///Users/suzmue/govulncheck-study/module5/go.mod"},"range":{"start":{"line":5,"character":1},"end":{"line":5,"character":32}},"context":{"diagnostics":[{"range":{"start":{"line":5,"character":1},"end":{"line":5,"character":32}},"message":"github.com/tidwall/gjson can be upgraded","severity":3,"source":"upgrade available"},{"range":{"start":{"line":5,"character":1},"end":{"line":5,"character":32}},"message":"Vulnerability found:\nA maliciously crafted path can cause Get and other query functions\nto consume excessive amounts of CPU and time.","code":"GO-2021-0265","codeDescription":{"href":"https://pkg.go.dev/vuln/GO-2021-0265"},"severity":2,"source":"vulncheck"}],"triggerKind":2}}

[DanTup]

@mjbvz can you confirm how this is intended to work? It seems to me like there are two ways of fixing this:

1. when opening the code actions list from a diagnostic, VS Code only includes that diagnostic in the list sent to the server (and the server filters)
2. VS Code filters the list of code actions to only those that have a diagnostic matching the one that's been clicked on

It's not clear to me which is correct. The first one seems to be what's described above, but that makes me wonder why CodeActions would have a diagnostics collection at all. If it's not intended to be used here, what is it for?

[mjbvz]

I think both would fix the issue (and we may want to do both).

I think the first fix is the more important one because it would let extensions / language servers avoid computing code actions for unrelated diagnostics. However the second fix may also be needed for misbehaving extensions that ignore the diagnostics on the code action request