Replaced error throw with diagnostic (#861)

Perryvw · web-flow · commit 375e009eb8a5 · 2020-05-09T17:15:37.000+02:00
* Replaced error throw with diagnostic

* Return nil if node is not a statement

* Handle expression case in transformExpression

* Throw error when expression visitor returns nothing

* Moved tests around

* Added error incase superTransform expression visitor returns nothing
diff --git a/src/transformation/context/context.ts b/src/transformation/context/context.ts
@@ -2,6 +2,7 @@ import * as ts from "typescript";
 import { CompilerOptions, LuaTarget } from "../../CompilerOptions";
 import * as lua from "../../LuaAST";
 import { castArray } from "../../utils";
+import { unsupportedNodeKind } from "../utils/diagnostics";
 import { unwrapVisitorResult } from "../utils/lua-ast";
 import { ExpressionLikeNode, ObjectVisitor, StatementLikeNode, VisitorMap } from "./visitors";
 
@@ -46,15 +47,21 @@ export class TransformationContext {
     }
 
     private currentNodeVisitors: Array<ObjectVisitor<ts.Node>> = [];
-    public transformNode(node: ts.Node): lua.Node[] {
+
+    public transformNode(node: ts.Node): lua.Node[];
+    /** @internal */
+    // eslint-disable-next-line @typescript-eslint/unified-signatures
+    public transformNode(node: ts.Node, isExpression?: boolean): lua.Node[];
+    public transformNode(node: ts.Node, isExpression?: boolean): lua.Node[] {
         // TODO: Move to visitors?
         if (node.modifiers?.some(modifier => modifier.kind === ts.SyntaxKind.DeclareKeyword)) {
             return [];
         }
 
         const nodeVisitors = this.visitorMap.get(node.kind);
         if (!nodeVisitors || nodeVisitors.length === 0) {
-            throw new Error(`Unsupported node kind: ${ts.SyntaxKind[node.kind]}.`);
+            this.diagnostics.push(unsupportedNodeKind(node, node.kind));
+            return isExpression ? [lua.createNilLiteral()] : [];
         }
 
         const previousNodeVisitors = this.currentNodeVisitors;
@@ -78,12 +85,22 @@ export class TransformationContext {
     }
 
     public transformExpression(node: ExpressionLikeNode): lua.Expression {
-        const [result] = this.transformNode(node);
+        const [result] = this.transformNode(node, true);
+
+        if (result === undefined) {
+            throw new Error(`Expression visitor for node type ${ts.SyntaxKind[node.kind]} did not return any result.`);
+        }
+
         return result as lua.Expression;
     }
 
     public superTransformExpression(node: ExpressionLikeNode): lua.Expression {
         const [result] = this.superTransformNode(node);
+
+        if (result === undefined) {
+            throw new Error(`Expression visitor for node type ${ts.SyntaxKind[node.kind]} did not return any result.`);
+        }
+
         return result as lua.Expression;
     }
 
diff --git a/src/transformation/utils/diagnostics.ts b/src/transformation/utils/diagnostics.ts
@@ -11,6 +11,10 @@ const createDiagnosticFactory = <TArgs extends any[]>(message: string | ((...arg
         messageText: typeof message === "string" ? message : message(...args),
     }));
 
+export const unsupportedNodeKind = createDiagnosticFactory(
+    (kind: ts.SyntaxKind) => `Unsupported node kind ${ts.SyntaxKind[kind]}`
+);
+
 export const forbiddenForIn = createDiagnosticFactory("Iterating over arrays with 'for ... in' is not allowed.");
 
 export const unsupportedNoSelfFunctionConversion = createDiagnosticFactory((name?: string) => {
diff --git a/test/unit/__snapshots__/statements.spec.ts.snap b/test/unit/__snapshots__/statements.spec.ts.snap
@@ -0,0 +1,8 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Unsupported node adds diagnostic: code 1`] = `
+"a = function()
+end"
+`;
+
+exports[`Unsupported node adds diagnostic: diagnostics 1`] = `"main.ts(3,13): error TSTL: Unsupported node kind LabeledStatement"`;
diff --git a/test/unit/expressions.spec.ts b/test/unit/expressions.spec.ts
@@ -2,15 +2,6 @@ import * as tstl from "../../src";
 import { unsupportedForTarget, unsupportedRightShiftOperator } from "../../src/transformation/utils/diagnostics";
 import * as util from "../util";
 
-// TODO:
-test("Block statement", () => {
-    util.testFunction`
-        let a = 4;
-        { let a = 42; }
-        return a;
-    `.expectToMatchJsResult();
-});
-
 test.each([
     "i++",
     "++i",
diff --git a/test/unit/statements.spec.ts b/test/unit/statements.spec.ts
@@ -0,0 +1,19 @@
+import * as util from "../util";
+import { unsupportedNodeKind } from "../../src/transformation/utils/diagnostics";
+
+test("Block statement", () => {
+    util.testFunction`
+        let a = 4;
+        { let a = 42; }
+        return a;
+    `.expectToMatchJsResult();
+});
+
+// https://github.com/TypeScriptToLua/TypeScriptToLua/issues/860
+test("Unsupported node adds diagnostic", () => {
+    util.testModule`
+        const a = () => {
+            foo: "bar"
+        };
+    `.expectDiagnosticsToMatchSnapshot([unsupportedNodeKind.code]);
+});
