From 876416dbdb80d2d4d5f1a10ea5c70b35e711db0c Mon Sep 17 00:00:00 2001
From: Mark Lundin <mlundin@snapchat.com>
Date: Mon, 16 Sep 2024 16:50:35 +0100
Subject: [PATCH] Fix type validation error in tag-utils.js

---
 src/utils/tag-utils.js           | 44 ++++++++++++++++++++------------
 test/fixtures/program.valid.js   |  8 ++++--
 test/tests/valid/program.test.js |  1 +
 3 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/src/utils/tag-utils.js b/src/utils/tag-utils.js
index ace641e..937d5e3 100644
--- a/src/utils/tag-utils.js
+++ b/src/utils/tag-utils.js
@@ -35,31 +35,41 @@ export function parseTag(input = '') {
 
 /**
  * Validates that a tag value matches the expected type
- * @throws {Error} - If the tag value is not the expected type
- *
- * @param {String} value - The string representation of the value to type check
- * @param {string} typeAnnotation - The expected type
- * @param {import('@typescript/vfs').VirtualTypeScriptEnvironment} env - The environment to validate in
- * @returns {boolean} - Whether the tag value is valid
+ * 
+ * @param value - The value to be validated.
+ * @param typeAnnotation - The TypeScript type annotation as a string.
+ * @param env - The environment containing the language service and file creation utilities.
+ * @throws Will throw an error if the value does not conform to the typeAnnotation.
+ * @returns `true` if validation passes without type errors.
  */
 export function validateTag(value, typeAnnotation, env) {
-
+    const virtualFileName = "/___virtual__.ts";
     const sourceText = `let a: ${typeAnnotation} = ${value};`;
-    env.createFile('/___virtual__.ts', sourceText);
 
-    // Get the program and check for semantic errors
-    const program = env.languageService.getProgram();
-    const errors = program.getSemanticDiagnostics();
+    // Create or overwrite the virtual file with the new source text
+    env.createFile(virtualFileName, sourceText);
+
+    // Retrieve the language service from the environment
+    const languageService = env.languageService;
+
+    // Fetch semantic diagnostics only for the virtual file
+    const errors = languageService.getSemanticDiagnostics(virtualFileName);
 
-    // Filter against the type errors we're concerned with
-    const typeErrors = errors.filter(error => error.category === 1 && error.code === 2322);
+    // Filter for type assignment errors (Error Code 2322: Type 'X' is not assignable to type 'Y')
+    const typeErrors = errors.filter(
+        error => error.code === 2322 && error.category === ts.DiagnosticCategory.Error
+    );
 
-    // return first error
-    const typeError = typeErrors[0];
+    // If any type error is found, throw an error with the diagnostic message
+    if (typeErrors.length > 0) {
+        // TypeScript's messageText can be a string or a DiagnosticMessageChain
+        const errorMessage = typeErrors[0].messageText instanceof ts.DiagnosticMessageChain
+            ? flattenDiagnosticMessageText(typeErrors[0].messageText, "\n")
+            : typeErrors[0].messageText.toString();
 
-    if (typeError) {
-        throw new Error(`${typeError.messageText}`);
+        throw new Error(`Type Validation Error: ${errorMessage}`);
     }
 
+    // If no type errors are found, return true indicating successful validation
     return true;
 }
diff --git a/test/fixtures/program.valid.js b/test/fixtures/program.valid.js
index 2cb91ed..6ff593d 100644
--- a/test/fixtures/program.valid.js
+++ b/test/fixtures/program.valid.js
@@ -8,13 +8,17 @@ export const MyEnum = { value: 0 };
 class Example extends Script {
     /**
      * @attribute
-     * @type {boolean}
+     * @precision 1
+     * @type {number}
      */
-    a = false;
+    a;
 
     initialize() {
         confetti();
         new TWEEN.Tween({ x: 0 }).to({ x: 100 }, 1000).start();
+
+        // This is an intentional type error, but the parser should ignore these
+        this.a = 'string';
     }
 }
 
diff --git a/test/tests/valid/program.test.js b/test/tests/valid/program.test.js
index 427b4d7..0d03ea3 100644
--- a/test/tests/valid/program.test.js
+++ b/test/tests/valid/program.test.js
@@ -13,5 +13,6 @@ describe('VALID: Program ', function () {
         expect(data).to.exist;
         expect(data[0]).to.not.be.empty;
         expect(data[1]).to.be.empty;
+        expect(data[0].example.errors).to.be.empty;
     });
 });