From 912bdd18681d46fd255aa7523fe426d51bdf2511 Mon Sep 17 00:00:00 2001
From: Dinika Saxena <dinikasaxenas@gmail.com>
Date: Thu, 5 Dec 2024 12:48:07 +0100
Subject: [PATCH] Throw error for numeric positional arg after yargs-parser has
 parsed args

Signed-off-by: Dinika Saxena <dinikasaxenas@gmail.com>
---
 lib/cli/options.js                 | 66 +++++++++++++++++++++---------
 test/node-unit/cli/options.spec.js |  8 ++++
 2 files changed, 55 insertions(+), 19 deletions(-)

diff --git a/lib/cli/options.js b/lib/cli/options.js
index 8ef5a28c6b..26199093be 100644
--- a/lib/cli/options.js
+++ b/lib/cli/options.js
@@ -103,6 +103,44 @@ const nargOpts = types.array
   .concat(types.string, types.number)
   .reduce((acc, arg) => Object.assign(acc, {[arg]: 1}), {});
 
+/**
+ * Throws either "UNSUPPORTED" error or "INVALID_ARG_TYPE" error for numeric positional arguments.
+ * @param {string[]} allArgs - Stringified args passed to mocha cli
+ * @param {number} numericArg - Numeric positional arg for which error must be thrown
+ * @param {Object} parsedResult - Result from `yargs-parser`
+ * @private
+ * @ignore
+ */
+const createErrorForNumericPositionalArg = (
+  allArgs,
+  numericArg,
+  parsedResult
+) => {
+  // A flag for `numericArg` exists if:
+  // 1. A mocha flag immediately preceeded the numericArg in `allArgs` array and
+  // 2. `numericArg` value could not be assigned to this flag by `yargs-parser` because of incompatible datatype.
+  const flag = allArgs.find((arg, index) => {
+    const normalizedArg = arg.replace(/^--?/, '');
+    return (
+      isMochaFlag(arg) &&
+      allArgs[index + 1] === String(numericArg) &&
+      parsedResult[normalizedArg] !== numericArg
+    );
+  });
+
+  if (flag) {
+    throw createInvalidArgumentTypeError(
+      `Mocha flag '${flag}' given invalid option: '${numericArg}'`,
+      numericArg,
+      expectedTypeForFlag(flag)
+    );
+  } else {
+    throw createUnsupportedError(
+      `Option ${numericArg} is unsupported by the mocha cli`
+    );
+  }
+};
+
 /**
  * Wrapper around `yargs-parser` which applies our settings
  * @param {string|string[]} args - Arguments to parse
@@ -120,25 +158,6 @@ const parse = (args = [], defaultValues = {}, ...configObjects) => {
   // 4. we can then reapply the values after yargs-parser is done.
   const allArgs = Array.isArray(args) ? args : args.split(' ');
   const nodeArgs = allArgs.reduce((acc, arg, index, allArgs) => {
-    const maybeFlag = allArgs[index - 1];
-
-    if (isNumeric(arg) && (!maybeFlag || !isMochaFlag(maybeFlag))) {
-      throw createUnsupportedError(
-        `Option ${arg} is unsupported by the mocha cli`
-      );
-    }
-    if (
-      isNumeric(arg) &&
-      isMochaFlag(maybeFlag) &&
-      expectedTypeForFlag(maybeFlag) !== 'number'
-    ) {
-      throw createInvalidArgumentTypeError(
-        `Mocha flag '${maybeFlag}' given invalid option: '${arg}'`,
-        Number(arg),
-        expectedTypeForFlag(maybeFlag)
-      );
-    }
-
     const pair = arg.split('=');
     let flag = pair[0];
     if (isNodeFlag(flag, false)) {
@@ -165,6 +184,15 @@ const parse = (args = [], defaultValues = {}, ...configObjects) => {
     process.exit(1);
   }
 
+  const numericPositionalArg = result.argv._.find(arg => isNumeric(arg));
+  if (numericPositionalArg) {
+    createErrorForNumericPositionalArg(
+      allArgs,
+      numericPositionalArg,
+      result.argv
+    );
+  }
+
   // reapply "=" arg values from above
   nodeArgs.forEach(([key, value]) => {
     result.argv[key] = value;
diff --git a/test/node-unit/cli/options.spec.js b/test/node-unit/cli/options.spec.js
index 2b6200fbcc..cb456869ae 100644
--- a/test/node-unit/cli/options.spec.js
+++ b/test/node-unit/cli/options.spec.js
@@ -771,6 +771,14 @@ describe('options', function () {
           'not to throw'
         );
       });
+
+      it('does not throw error if numeric value is passed to string flag', function () {
+        expect(() => loadOptions(`--grep ${numericArg}`), 'not to throw');
+      });
+
+      it('does not throw error if numeric value is passed to an array flag', function () {
+        expect(() => loadOptions(`--spec ${numericArg}`), 'not to throw');
+      });
     });
   });
 });