fix(spawn): add EBADF fallback using temp files (fixes #3556)

src/process/spawn-utils.ts

@@ -1,5 +1,10 @@
 import type { ChildProcess, SpawnOptions } from "node:child_process";
-import { spawn } from "node:child_process";
+import { spawn, spawnSync } from "node:child_process";
+import { EventEmitter } from "node:events";
+import { PassThrough } from "node:stream";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
 
 export type SpawnFallback = {
   label: string;
@@ -49,12 +54,112 @@ function shouldRetry(err: unknown, codes: string[]): boolean {
   return code.length > 0 && codes.includes(code);
 }
 
+// EBADF workaround: capture output via temp files, use stdio: ignore for spawn
+function createFakeChildFromSync(argv: string[], options: SpawnOptions): ChildProcess {
+  const child = new EventEmitter() as unknown as ChildProcess;
+  const stdout = new PassThrough();
+  const stderr = new PassThrough();
+
+  child.stdout = stdout;
+  child.stderr = stderr;
+  child.stdin = new PassThrough();
+  child.pid = process.pid;
+  child.killed = false;
+  child.kill = () => {
+    child.killed = true;
+    return true;
+  };
+
+  // Extract command from argv (typically [shell, "-c", command])
+  const command = argv.length >= 3 ? argv[2] : argv.join(" ");
+
+  // Create temp files for output capture
+  const tmpDir = os.tmpdir();
+  const id = `clawdbot-ebadf-${Date.now()}-${Math.random().toString(36).slice(2)}`;
+  const stdoutFile = path.join(tmpDir, `${id}.stdout`);
+  const stderrFile = path.join(tmpDir, `${id}.stderr`);
+
+  // Wrap command to redirect output to files
+  const wrappedCommand = `( ${command} ) > "${stdoutFile}" 2> "${stderrFile}"`;
+
+  setImmediate(() => {
+    try {
+      // spawnSync with stdio: ignore - no pipes needed
+      const result = spawnSync("/bin/sh", ["-c", wrappedCommand], {
+        cwd: options.cwd || process.cwd(),
+        timeout: 300000,
+        stdio: "ignore",
+      });
+
+      if (result.error) {
+        // Clean up temp files
+        try {
+          fs.unlinkSync(stdoutFile);
+        } catch {}
+        try {
+          fs.unlinkSync(stderrFile);
+        } catch {}
+        child.emit("error", result.error);
+        return;
+      }
+
+      child.pid = result.pid || process.pid;
+
+      // Read output from temp files
+      try {
+        const stdoutData = fs.readFileSync(stdoutFile, "utf8");
+        if (stdoutData) stdout.write(stdoutData);
+      } catch {}
+
+      try {
+        const stderrData = fs.readFileSync(stderrFile, "utf8");
+        if (stderrData) stderr.write(stderrData);
+      } catch {}
+
+      // Clean up temp files
+      try {
+        fs.unlinkSync(stdoutFile);
+      } catch {}
+      try {
+        fs.unlinkSync(stderrFile);
+      } catch {}
+
+      stdout.end();
+      stderr.end();
+      child.emit("close", result.status, result.signal);
+    } catch (err) {
+      // Clean up temp files
+      try {
+        fs.unlinkSync(stdoutFile);
+      } catch {}
+      try {
+        fs.unlinkSync(stderrFile);
+      } catch {}
+      child.emit("error", err);
+    }
+  });
+
+  // Emit spawn immediately
+  process.nextTick(() => {
+    child.emit("spawn");
+  });
+
+  return child;
+}
+
 async function spawnAndWaitForSpawn(
   spawnImpl: typeof spawn,
   argv: string[],
   options: SpawnOptions,
+  useSyncFallback = false,
 ): Promise<ChildProcess> {
-  const child = spawnImpl(argv[0], argv.slice(1), options);
+  let child: ChildProcess;
+
+  if (useSyncFallback) {
+    child = createFakeChildFromSync(argv, options);
+  } else {
+    child = spawnImpl(argv[0], argv.slice(1), options);
+  }
 
   return await new Promise((resolve, reject) => {
     let settled = false;
@@ -95,19 +200,27 @@ export async function spawnWithFallback(
   const retryCodes = params.retryCodes ?? DEFAULT_RETRY_CODES;
   const baseOptions = { ...params.options };
   const fallbacks = params.fallbacks ?? [];
-  const attempts: Array<{ label?: string; options: SpawnOptions }> = [
+  const attempts: Array<{ label?: string; options: SpawnOptions; useSync?: boolean }> = [
-    { options: baseOptions },
+    { options: baseOptions, useSync: false },
     ...fallbacks.map((fallback) => ({
       label: fallback.label,
       options: { ...baseOptions, ...fallback.options },
+      useSync: false,
     })),
+    // Final EBADF fallback: spawnSync with stdio:ignore + file capture
+    { label: "file-capture", options: baseOptions, useSync: true },
   ];
 
   let lastError: unknown;
   for (let index = 0; index < attempts.length; index += 1) {
     const attempt = attempts[index];
     try {
-      const child = await spawnAndWaitForSpawn(spawnImpl, params.argv, attempt.options);
+      const child = await spawnAndWaitForSpawn(
+        spawnImpl,
+        params.argv,
+        attempt.options,
+        attempt.useSync,
+      );
       return {
         child,
         usedFallback: index > 0,
@@ -115,11 +228,16 @@ export async function spawnWithFallback(
       };
     } catch (err) {
       lastError = err;
-      const nextFallback = fallbacks[index];
+      const nextAttempt = attempts[index + 1];
-      if (!nextFallback || !shouldRetry(err, retryCodes)) {
+      if (!nextAttempt || !shouldRetry(err, retryCodes)) {
         throw err;
       }
-      params.onFallback?.(err, nextFallback);
+      if (nextAttempt.label) {
+        params.onFallback?.(err, {
+          label: nextAttempt.label,
+          options: nextAttempt.options,
+        });
+      }
     }
   }