x/tools/gopls/internal/lsp/protocol: CodeAction.Edit is always serialized

[briandealwis]

protocol.CodeAction can't be used to lazily compute workspace edits with codeAction/resolve as protocol.CodeAction.Edit is a struct value, and not a pointer to a struct, and is thus always serialized even when a zero value:

// The workspace edit this code action performs.
Edit WorkspaceEdit `json:"edit,omitempty"`

I see in serialized output:

I0224 09:15:34.328959      63 conn_opt.go:96] jsonrpc2: <-- result #3: textDocument/codeAction: [{"title":"...","kind":"quickfix","diagnostics":[...],"edit":{},"data":{...}},...]

omitempty is not applied by json.Marshal for zero-value structs (see #11939):

The "omitempty" option specifies that the field should be omitted from the encoding if the field has an empty value, defined as false, 0, a nil pointer, a nil interface value, and any empty array, slice, map, or string.

I think the solution is for {"CodeAction", "edit"} to be marked as wantOptStar:

	{"CodeAction", "edit"}:                                       wantOpt,

cc: @hyangah

[hyangah]

cc @pjweinb

[pjweinb]

Yes, this is a bug. (It was this way for backwards compatibility, but it can now be fixed. There are a lot of these.) I'll try to fix it fairly soon.

…

On Fri, Feb 24, 2023 at 9:25 AM Hyang-Ah Hana Kim ***@***.***> wrote: cc @pjweinb <https://github.com/pjweinb> — Reply to this email directly, view it on GitHub <#58687 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABJIAI725ZXFGBI6T7SYQ5DWZDAGZANCNFSM6AAAAAAVG6UAY4> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[pjweinb]

This was fixed by https://go-review.git.corp.google.com/c/tools/+/472656 .