Add specific empty function name compiler error

This commit adds checks to rjeect functions with empty or whitespace
names. The compiler throws a specific errror when it encounters a
function data object lacking a proper name.

This provides early detection and clear feedback on invalid function
definitions, helping in faster debugging and ensuring script integrity
in the compilation process.

The enhancement aims to provide early detection and clear feedback
on invalid function definitions, aiding in faster debugging and
ensuring script integrity in the compilation process.

when it encounters a function data object lacking a proper name.
It covers scenarios where the function name might be an empty string,
undefined, or solely consist of whitespace.

src/application/Parser/Script/Compiler/Function/SharedFunctionsParser.ts

@@ -98,6 +98,7 @@ function hasCall(data: FunctionData): data is CallFunctionData {
 }
 
 function ensureValidFunctions(functions: readonly FunctionData[]) {
+  ensureNoUnnamedFunctions(functions);
   ensureNoDuplicatesInFunctionNames(functions);
   ensureEitherCallOrCodeIsDefined(functions);
   ensureNoDuplicateCode(functions);
@@ -108,6 +109,16 @@ function printList(list: readonly string[]): string {
   return `"${list.join('","')}"`;
 }
 
+function ensureNoUnnamedFunctions(functions: readonly FunctionData[]) {
+  const functionsWithoutNames = functions.filter(
+    (func) => !func.name || func.name.trim().length === 0,
+  );
+  if (functionsWithoutNames.length) {
+    const invalidFunctions = functionsWithoutNames.map((f) => JSON.stringify(f));
+    throw new Error(`Some function(s) have no names:\n${invalidFunctions.join('\n')}`);
+  }
+}
+
 function ensureEitherCallOrCodeIsDefined(holders: readonly FunctionData[]) {
   // Ensure functions do not define both call and code
   const withBothCallAndCode = holders.filter((holder) => hasCode(holder) && hasCall(holder));

tests/unit/application/Parser/Script/Compiler/Function/SharedFunctionsParser.spec.ts

@@ -26,6 +26,27 @@ describe('SharedFunctionsParser', () => {
   });
   describe('parseFunctions', () => {
     describe('validates functions', () => {
+      it('throws when functions have no names', () => {
+        // arrange
+        const invalidFunctions = [
+          createFunctionDataWithCode()
+            .withCode('test function 1')
+            .withName(' '), // Whitespace,
+          createFunctionDataWithCode()
+            .withCode('test function 2')
+            .withName(undefined as unknown as string), // Undefined
+          createFunctionDataWithCode()
+            .withCode('test function 3')
+            .withName(''), // Empty
+        ];
+        const expectedError = `Some function(s) have no names:\n${invalidFunctions.map((f) => JSON.stringify(f)).join('\n')}`;
+        // act
+        const act = () => new ParseFunctionsCallerWithDefaults()
+          .withFunctions(invalidFunctions)
+          .parseFunctions();
+        // assert
+        expect(act).to.throw(expectedError);
+      });
       it('throws when functions have same names', () => {
         // arrange
         const name = 'same-func-name';