Rework flag protection

src/internal/win/powershell.js

@@ -112,6 +112,6 @@ export function getQuoteFunction() {
  * @returns {function(string): string} A function to protect against flag injection.
  */
 export function getFlagProtectionFunction() {
-  const leadingHyphensAndSlashes = new RegExp(/^(?:`?-+|\/+)/);
+  const leadingHyphensAndSlashes = new RegExp(/^(?:-+|\/+)/);
   return (arg) => arg.replace(leadingHyphensAndSlashes, "");
 }

test/fixtures/win.js

@@ -4304,6 +4304,32 @@ export const flag = {
         expected: { unquoted: "a=b", quoted: "'a=b'" },
       },
     ],
+    "hyphen (-) + backtick (`)": [
+      {
+        input: "`-a",
+        expected: { unquoted: "`-a", quoted: "'`-a'" },
+      },
+      {
+        input: "`-a=b",
+        expected: { unquoted: "`-a=b", quoted: "'`-a=b'" },
+      },
+      {
+        input: "`--a",
+        expected: { unquoted: "`--a", quoted: "'`--a'" },
+      },
+      {
+        input: "`--a=b",
+        expected: { unquoted: "`--a=b", quoted: "'`--a=b'" },
+      },
+      {
+        input: "`---a",
+        expected: { unquoted: "`---a", quoted: "'`---a'" },
+      },
+      {
+        input: "`---a=b",
+        expected: { unquoted: "`---a=b", quoted: "'`---a=b'" },
+      },
+    ],
     "forward slash (/)": [
       {
         input: "/a",