refactor(utils): share shell argv tokenizer

src/infra/exec-approvals-analysis.ts

@@ -2,6 +2,7 @@ import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import type { ExecAllowlistEntry } from "./exec-approvals.js";
+import { splitShellArgs } from "../utils/shell-argv.js";
 
 export const DEFAULT_SAFE_BINS = ["jq", "grep", "cut", "sort", "uniq", "head", "tail", "tr", "wc"];
 
@@ -582,75 +583,6 @@ export function isWindowsPlatform(platform?: string | null): boolean {
   return normalized.startsWith("win");
 }
 
-function tokenizeShellSegment(segment: string): string[] | null {
-  const tokens: string[] = [];
-  let buf = "";
-  let inSingle = false;
-  let inDouble = false;
-  let escaped = false;
-
-  const pushToken = () => {
-    if (buf.length > 0) {
-      tokens.push(buf);
-      buf = "";
-    }
-  };
-
-  for (let i = 0; i < segment.length; i += 1) {
-    const ch = segment[i];
-    if (escaped) {
-      buf += ch;
-      escaped = false;
-      continue;
-    }
-    if (!inSingle && !inDouble && ch === "\\") {
-      escaped = true;
-      continue;
-    }
-    if (inSingle) {
-      if (ch === "'") {
-        inSingle = false;
-      } else {
-        buf += ch;
-      }
-      continue;
-    }
-    if (inDouble) {
-      const next = segment[i + 1];
-      if (ch === "\\" && isDoubleQuoteEscape(next)) {
-        buf += next;
-        i += 1;
-        continue;
-      }
-      if (ch === '"') {
-        inDouble = false;
-      } else {
-        buf += ch;
-      }
-      continue;
-    }
-    if (ch === "'") {
-      inSingle = true;
-      continue;
-    }
-    if (ch === '"') {
-      inDouble = true;
-      continue;
-    }
-    if (/\s/.test(ch)) {
-      pushToken();
-      continue;
-    }
-    buf += ch;
-  }
-
-  if (escaped || inSingle || inDouble) {
-    return null;
-  }
-  pushToken();
-  return tokens;
-}
-
 function parseSegmentsFromParts(
   parts: string[],
   cwd?: string,
@@ -658,7 +590,7 @@ function parseSegmentsFromParts(
 ): ExecCommandSegment[] | null {
   const segments: ExecCommandSegment[] = [];
   for (const raw of parts) {
-    const argv = tokenizeShellSegment(raw);
+    const argv = splitShellArgs(raw);
     if (!argv || argv.length === 0) {
       return null;
     }

src/utils/shell-argv.test.ts

@@ -0,0 +1,19 @@
+import { describe, expect, it } from "vitest";
+import { splitShellArgs } from "./shell-argv.js";
+
+describe("splitShellArgs", () => {
+  it("splits whitespace and respects quotes", () => {
+    expect(splitShellArgs(`qmd --foo "bar baz"`)).toEqual(["qmd", "--foo", "bar baz"]);
+    expect(splitShellArgs(`qmd --foo 'bar baz'`)).toEqual(["qmd", "--foo", "bar baz"]);
+  });
+
+  it("supports backslash escapes inside double quotes", () => {
+    expect(splitShellArgs(String.raw`echo "a\"b"`)).toEqual(["echo", `a"b`]);
+    expect(splitShellArgs(String.raw`echo "\$HOME"`)).toEqual(["echo", "$HOME"]);
+  });
+
+  it("returns null for unterminated quotes", () => {
+    expect(splitShellArgs(`echo "oops`)).toBeNull();
+    expect(splitShellArgs(`echo 'oops`)).toBeNull();
+  });
+});

src/utils/shell-argv.ts

@@ -1,3 +1,9 @@
+const DOUBLE_QUOTE_ESCAPES = new Set(["\\", '"', "$", "`", "\n", "\r"]);
+
+function isDoubleQuoteEscape(next: string | undefined): next is string {
+  return Boolean(next && DOUBLE_QUOTE_ESCAPES.has(next));
+}
+
 export function splitShellArgs(raw: string): string[] | null {
   const tokens: string[] = [];
   let buf = "";
@@ -32,6 +38,12 @@ export function splitShellArgs(raw: string): string[] | null {
       continue;
     }
     if (inDouble) {
+      const next = raw[i + 1];
+      if (ch === "\\" && isDoubleQuoteEscape(next)) {
+        buf += next;
+        i += 1;
+        continue;
+      }
       if (ch === '"') {
         inDouble = false;
       } else {