Windows standalone executable crashes spawning Worker when autoloadDotenv=false and .env exists #27431

What version of Bun is running?

1.3.10-canary.104+32a89c433

What platform is your computer?

Microsoft Windows NT 10.0.22631.0 x64

What steps can reproduce the bug?

Repro repo: https://github.com/Hona/bun1310-minimal-repro

Run this in a directory containing a .env file:

bun repro-short.ts

The script is:

await Bun.write("r.ts", 'new Worker("data:text/javascript,")\n');
await Bun.build({
  entrypoints: ["./r.ts"],
  compile: {
    autoloadDotenv: false,
    target: "bun-windows-x64",
    outfile: "./r.exe",
  },
});
Bun.spawnSync(["./r.exe"], {
  stdin: "inherit",
  stdout: "inherit",
  stderr: "inherit",
});

This reduces to:

• build a standalone executable
• set compile.autoloadDotenv = false
• run the executable in a cwd that contains .env
• have the executable do new Worker(...)

On my machine, removing any one of those stops reproducing.

What is the expected behavior?

The standalone executable should exit cleanly. The presence of a .env file in cwd should not matter when autoloadDotenv is disabled.

What do you see instead?

The compiled executable panics immediately:

panic(thread ...): Internal assertion failure: `ThreadLock` is locked by thread ..., not thread ...
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

One sample crash from this repro:

============================================================
Bun Canary v1.3.10-canary.104 (32a89c43) Windows x64
Windows v.win11_ge
CPU: sse42 avx avx2
Args: "./r.exe"
Features: jsc standalone_executable workers_spawned
Builtins: "bun:main"
Elapsed: 51ms | User: 15ms | Sys: 15ms
RSS: 0.14GB | Peak: 0.14GB | Commit: 0.39GB | Faults: 34252 | Machine: 34.03GB

panic(thread 48292): Internal assertion failure: `ThreadLock` is locked by thread 58860, not thread 48292
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Additional information

Confirmed non-factors in this repro:

• extra exec flags are not required
• custom worker files are not required
• worker contents are not required
• explicit env passing is not required
• process.chdir() is not required

Confirmed sanity checks:

• removing .env avoids the crash
• leaving autoloadDotenv at its default avoids the crash
• removing the Worker avoids the crash