From a0cf054a4555933c163d9bff1b5395fa6de484ac Mon Sep 17 00:00:00 2001
From: Suzy Mueller <suzmue@golang.org>
Date: Wed, 14 Aug 2019 15:24:21 -0400
Subject: [PATCH] internal/lsp: initialize CodeActionProvider with supported
 actions

Send the code action kinds that we support, if codeActionLiteralSupport
is specified. Editors may use the CodeActionKinds that we support to
determine UI layout for example.

Change-Id: Iee368aa02c26f4395bb2894593ef38d84d3283b7
Reviewed-on: https://go-review.googlesource.com/c/tools/+/191620
Run-TryBot: Suzy Mueller <suzmue@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
---
 internal/lsp/code_action.go         | 19 +++++++++++++++++++
 internal/lsp/general.go             | 15 ++++++++++++++-
 internal/lsp/protocol/tsprotocol.go |  2 +-
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/internal/lsp/code_action.go b/internal/lsp/code_action.go
index 2c6f065624..6b61894ace 100644
--- a/internal/lsp/code_action.go
+++ b/internal/lsp/code_action.go
@@ -7,6 +7,7 @@ package lsp
 import (
 	"context"
 	"fmt"
+	"sort"
 	"strings"
 
 	"golang.org/x/tools/internal/imports"
@@ -18,6 +19,24 @@ import (
 	errors "golang.org/x/xerrors"
 )
 
+func (s *Server) getSupportedCodeActions() []protocol.CodeActionKind {
+	allCodeActionKinds := make(map[protocol.CodeActionKind]struct{})
+	for _, kinds := range s.supportedCodeActions {
+		for kind := range kinds {
+			allCodeActionKinds[kind] = struct{}{}
+		}
+	}
+
+	var result []protocol.CodeActionKind
+	for kind := range allCodeActionKinds {
+		result = append(result, kind)
+	}
+	sort.Slice(result, func(i, j int) bool {
+		return result[i] < result[j]
+	})
+	return result
+}
+
 func (s *Server) codeAction(ctx context.Context, params *protocol.CodeActionParams) ([]protocol.CodeAction, error) {
 	uri := span.NewURI(params.TextDocument.URI)
 	view := s.session.ViewOf(uri)
diff --git a/internal/lsp/general.go b/internal/lsp/general.go
index b946abe5d4..51f9f438ed 100644
--- a/internal/lsp/general.go
+++ b/internal/lsp/general.go
@@ -77,9 +77,22 @@ func (s *Server) initialize(ctx context.Context, params *protocol.InitializePara
 			return nil, err
 		}
 	}
+
+	var codeActionProvider interface{}
+	if len(params.Capabilities.TextDocument.CodeAction.CodeActionLiteralSupport.CodeActionKind.ValueSet) > 0 {
+		// If the client has specified CodeActionLiteralSupport,
+		// send the code actions we support.
+		//
+		// Using CodeActionOptions is only valid if codeActionLiteralSupport is set.
+		codeActionProvider = &protocol.CodeActionOptions{
+			CodeActionKinds: s.getSupportedCodeActions(),
+		}
+	} else {
+		codeActionProvider = true
+	}
 	return &protocol.InitializeResult{
 		Capabilities: protocol.ServerCapabilities{
-			CodeActionProvider: true,
+			CodeActionProvider: codeActionProvider,
 			CompletionProvider: &protocol.CompletionOptions{
 				TriggerCharacters: []string{"."},
 			},
diff --git a/internal/lsp/protocol/tsprotocol.go b/internal/lsp/protocol/tsprotocol.go
index b9e81ebe20..b7a627e35b 100644
--- a/internal/lsp/protocol/tsprotocol.go
+++ b/internal/lsp/protocol/tsprotocol.go
@@ -1528,7 +1528,7 @@ type ServerCapabilities struct {
 	 * specified if the client states that it supports
 	 * `codeActionLiteralSupport` in its initial `initialize` request.
 	 */
-	CodeActionProvider bool `json:"codeActionProvider,omitempty"` // boolean | CodeActionOptions
+	CodeActionProvider interface{} `json:"codeActionProvider,omitempty"` // boolean | CodeActionOptions
 
 	/*CodeLensProvider defined:
 	 * The server provides code lens.