From c8e85b962a58929cc272d966cfc0dd6e2409ed1d Mon Sep 17 00:00:00 2001
From: Naimur Reza <95697060+naimur-reza@users.noreply.github.com>
Date: Tue, 13 Oct 2026 19:46:27 +0600
Subject: [PATCH] fix(javascript): recover child-process options without args
 (#2781)
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* docs: celebrate 180,000 GitHub stars 🎉

* fix(javascript): recover child-process options without args

* fix(javascript): preserve execFile callback overload options

Choose execFile options by the second argument object shape rather than total argument count, preserving callback overloads.

Source inspection and git diff --check; tests/builds/typechecks/CI reruns skipped at explicit user request.

---------

Co-authored-by: morluto <76467478+morluto@users.noreply.github.com>
---
 README.md                                     |  2 +-
 .../childProcessOptionsRegression.test.ts     | 97 +++++++++++++++++++
 .../javascriptSemanticChildProcesses.ts       | 13 ++-
 3 files changed, 107 insertions(+), 5 deletions(-)
 create mode 100644 src/domain/javascript/childProcessOptionsRegression.test.ts

diff --git a/README.md b/README.md
index c4a89bceee..05b4179598 100644
--- a/README.md
+++ b/README.md
@@ -322,7 +322,7 @@ Report vulnerabilities through [SECURITY.md](SECURITY.md).
 
 ## Star history
 
-🎉 **170,000 GitHub stars — thank you!**
+🎉 **180,000 GitHub stars — thank you!**
 
 Thanks to everyone using REA, reporting bugs, requesting features, testing builds, and contributing fixes.
 
diff --git a/src/domain/javascript/childProcessOptionsRegression.test.ts b/src/domain/javascript/childProcessOptionsRegression.test.ts
new file mode 100644
index 0000000000..8c18fe8305
--- /dev/null
+++ b/src/domain/javascript/childProcessOptionsRegression.test.ts
@@ -0,0 +1,97 @@
+import { describe, expect, it } from "vitest";
+import { analyzeJavaScriptSemantics } from "./javascriptSemanticAnalysis.js";
+
+describe("child-process options detection", () => {
+  it("detects options without an args array", () => {
+    const ir = analyzeJavaScriptSemantics(`
+      import { spawn, execFile, fork } from "node:child_process";
+
+      spawn("tool", {
+        env: { A: "1" },
+        stdio: "pipe"
+      });
+
+      execFile("tool", {
+        env: { A: "1" }
+      });
+
+      fork("worker.js", {
+        env: { A: "1" },
+        stdio: ["pipe", "pipe", "pipe", "ipc"]
+      });
+    `);
+
+    expect(
+      ir.childProcessSpawns.map(
+        ({ method, environmentSupplied, stdioMode, resolution }) => ({
+          method,
+          environmentSupplied,
+          stdioMode,
+          resolution,
+        }),
+      ),
+    ).toEqual([
+      {
+        method: "spawn",
+        environmentSupplied: true,
+        stdioMode: "pipe",
+        resolution: "complete",
+      },
+      {
+        method: "execFile",
+        environmentSupplied: true,
+        stdioMode: "default",
+        resolution: "complete",
+      },
+      {
+        method: "fork",
+        environmentSupplied: true,
+        stdioMode: "array",
+        resolution: "complete",
+      },
+    ]);
+  });
+
+  it("preserves behavior with explicit args arrays", () => {
+    const ir = analyzeJavaScriptSemantics(`
+      import { spawn, execFile, fork } from "node:child_process";
+
+      spawn("tool", [], { env: { A: "1" }, stdio: "pipe" });
+      execFile("tool", [], { env: { A: "1" } });
+      fork("worker.js", [], {
+        env: { A: "1" },
+        stdio: ["pipe", "pipe", "pipe", "ipc"]
+      });
+    `);
+
+    expect(
+      ir.childProcessSpawns.map(({ environmentSupplied, stdioMode }) => ({
+        environmentSupplied,
+        stdioMode,
+      })),
+    ).toEqual([
+      { environmentSupplied: true, stdioMode: "pipe" },
+      { environmentSupplied: true, stdioMode: "default" },
+      { environmentSupplied: true, stdioMode: "array" },
+    ]);
+  });
+
+  it("does not invent options when omitted", () => {
+    const ir = analyzeJavaScriptSemantics(`
+      import { spawn, execFile, fork } from "node:child_process";
+
+      spawn("tool");
+      execFile("tool");
+      fork("worker.js");
+    `);
+
+    expect(
+      ir.childProcessSpawns.every(
+        ({ environmentSupplied, stdioMode }) =>
+          environmentSupplied === false && stdioMode === "default",
+      ),
+    ).toBe(true);
+
+    expect(ir.childProcessSpawns).toHaveLength(3);
+  });
+});
diff --git a/src/domain/javascript/javascriptSemanticChildProcesses.ts b/src/domain/javascript/javascriptSemanticChildProcesses.ts
index fe7b5e8022..0fd0c9a35f 100644
--- a/src/domain/javascript/javascriptSemanticChildProcesses.ts
+++ b/src/domain/javascript/javascriptSemanticChildProcesses.ts
@@ -324,13 +324,18 @@ const resolveChildCandidates = (
     ? []
     : (spawnsByBinding.get(binding.bindingId) ?? []);
 };
-
 const spawnOptions = (candidate: SpawnCandidate): t.ObjectExpression | null => {
-  const index = candidate.method === "exec" ? 1 : 2;
-  const value = candidate.node.arguments[index];
+  const args = candidate.node.arguments;
+
+  const value =
+    candidate.method === "exec"
+      ? args[1]
+      : t.isObjectExpression(args[1])
+        ? args[1]
+        : args[2];
+
   return t.isObjectExpression(value) ? value : null;
 };
-
 const spawnArgvCount = (candidate: SpawnCandidate): number | null => {
   if (candidate.method === "exec") return null;
   const args = candidate.node.arguments[1];