(GH-327) Format on save code action

This adds a code action to format a file based on the `editor.codeActionsOnSave` setting. This can either be a global setting or one specific to the terraform language.

internal/langserver/handlers/code_action.go

@@ -0,0 +1,57 @@
+package handlers
+
+import (
+	"context"
+
+	lsp "github.com/hashicorp/terraform-ls/internal/protocol"
+)
+
+func (h *logHandler) TextDocumentCodeAction(ctx context.Context, params lsp.CodeActionParams) ([]lsp.CodeAction, error) {
+	ca := make([]lsp.CodeAction, 0)
+
+	h.logger.Printf("got %+v", params)
+
+	for _, action := range params.Context.Only {
+		c := getCodeAction(action)
+		ca = append(ca, c)
+	}
+
+	return ca, nil
+}
+
+func getCodeAction(action lsp.CodeActionKind) lsp.CodeAction {
+	switch action {
+	case lsp.Source:
+		return lsp.CodeAction{
+			Title:       "Format Document",
+			Kind:        lsp.SourceFixAll,
+			IsPreferred: false,
+			Command: &lsp.Command{
+				Title:   "Format Document",
+				Command: "editor.action.formatDocument",
+			},
+		}
+	case lsp.SourceFixAll:
+		return lsp.CodeAction{
+			Title:       "Format Document",
+			Kind:        lsp.SourceFixAll,
+			IsPreferred: false,
+			Command: &lsp.Command{
+				Title:   "Format Document",
+				Command: "editor.action.formatDocument",
+			},
+		}
+	// case "formatModified":
+	// 	return lsp.CodeAction{
+	// 		Title:       "Format Modified",
+	// 		Kind:        "formatModified",
+	// 		IsPreferred: false,
+	// 		Command: &lsp.Command{
+	// 			Title:   "Format Modified",
+	// 			Command: "editor.action.formatChanges",
+	// 		},
+	// 	}
+	default:
+		return lsp.CodeAction{}
+	}
+}

internal/langserver/handlers/initialize.go

@@ -25,6 +25,15 @@ func (svc *service) Initialize(ctx context.Context, params lsp.InitializeParams)
 				ResolveProvider:   false,
 				TriggerCharacters: []string{".", "["},
 			},
+			CodeActionProvider: lsp.CodeActionOptions{
+				CodeActionKinds: []lsp.CodeActionKind{
+					lsp.Source,
+					lsp.SourceFixAll,
+				},
+
+				ResolveProvider:         false,
+				WorkDoneProgressOptions: lsp.WorkDoneProgressOptions{},
+			},
 			DeclarationProvider:        lsp.DeclarationOptions{},
 			DefinitionProvider:         true,
 			CodeLensProvider:           lsp.CodeLensOptions{},

internal/langserver/handlers/service.go

@@ -231,6 +231,18 @@ func (svc *service) Assigner() (jrpc2.Assigner, error) {
 
 			return handle(ctx, req, lh.TextDocumentHover)
 		},
+		"textDocument/codeAction": func(ctx context.Context, req *jrpc2.Request) (interface{}, error) {
+			err := session.CheckInitializationIsConfirmed()
+			if err != nil {
+				return nil, err
+			}
+
+			ctx = lsctx.WithClientCapabilities(ctx, cc)
+			ctx = lsctx.WithDocumentStorage(ctx, svc.fs)
+			ctx = lsctx.WithModuleFinder(ctx, svc.modMgr)
+
+			return handle(ctx, req, lh.TextDocumentCodeAction)
+		},
 		"textDocument/codeLens": func(ctx context.Context, req *jrpc2.Request) (interface{}, error) {
 			err := session.CheckInitializationIsConfirmed()
 			if err != nil {