util: do not treat a dash in a short option group as the terminator

lib/internal/util/parse_args/parse_args.js

@@ -192,11 +192,22 @@ function argsToTokens(args, options) {
   while (remainingArgs.length > 0) {
     const arg = ArrayPrototypeShift(remainingArgs);
     const nextArg = remainingArgs[0];
-    if (groupCount > 0)
+    const isFromGroup = groupCount > 0;
+    if (isFromGroup)
       groupCount--;
     else
       index++;
 
+    if (isFromGroup && arg === '--') {
+      // A '-' inside a short option group, e.g. '-a-b'. It was expanded to
+      // '--' but is not the options terminator, so report it as an option.
+      ArrayPrototypePush(
+        tokens,
+        { kind: 'option', name: findLongOptionForShort('-', options),
+          rawName: '-', index, value: undefined, inlineValue: undefined });
+      continue;
+    }
+
     // Check if `arg` is an options terminator.
     // Guideline 10 in https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html
     if (arg === '--') {

test/parallel/test-parse-args.mjs

@@ -336,6 +336,24 @@ test('unknown option -r in short option group -bar', () => {
   });
 });
 
+test("strict: '-' inside short option group -a-b is an unknown option", () => {
+  const args = ['-a-b'];
+  const options = { a: { type: 'boolean' }, b: { type: 'boolean' } };
+  assert.throws(() => { parseArgs({ args, options }); }, {
+    code: 'ERR_PARSE_ARGS_UNKNOWN_OPTION',
+    message: /Unknown option '-'/,
+  });
+});
+
+test("strict: trailing '-' in short option group -a- is an unknown option", () => {
+  const args = ['-a-'];
+  const options = { a: { type: 'boolean' } };
+  assert.throws(() => { parseArgs({ args, options }); }, {
+    code: 'ERR_PARSE_ARGS_UNKNOWN_OPTION',
+    message: /Unknown option '-'/,
+  });
+});
+
 test('unknown option with explicit value', () => {
   const args = ['--foo', '--bar=baz'];
   const options = { foo: { type: 'boolean' } };
@@ -748,6 +766,26 @@ test('tokens: strict:true complex option group with value after space', () => {
   assert.deepStrictEqual(tokens, expectedTokens);
 });
 
+test("tokens: '-' inside short option group is not an option terminator", () => {
+  // Also positional to check index correct afterwards.
+  const args = ['-a-b', 'pos'];
+  const options = {
+    alpha: { short: 'a', type: 'boolean' },
+    beta: { short: 'b', type: 'boolean' },
+  };
+  const expectedTokens = [
+    { kind: 'option', name: 'alpha', rawName: '-a',
+      index: 0, value: undefined, inlineValue: undefined },
+    { kind: 'option', name: '-', rawName: '-',
+      index: 0, value: undefined, inlineValue: undefined },
+    { kind: 'option', name: 'beta', rawName: '-b',
+      index: 0, value: undefined, inlineValue: undefined },
+    { kind: 'positional', index: 1, value: 'pos' },
+  ];
+  const { tokens } = parseArgs({ strict: false, allowPositionals: true, args, options, tokens: true });
+  assert.deepStrictEqual(tokens, expectedTokens);
+});
+
 test('tokens: strict:true complex option group with inline value', () => {
   // Also positional to check index correct afterwards.
   const args = ['-abc', 'pos'];