uv build panicing @ the modal disco in src/commands/build.rs

[anthonycorletti]

Hello!

I experienced an interesting quirk when I was building images on Modal (modal.com). uv build fails during image creation when I define an image like so:

# here's the definition
image = (
    Image.debian_slim()
    .pip_install("uv")
    .copy_local_file("pyproject.toml", "/pyproject.toml")
    .copy_local_file("uv.lock", "/uv.lock")
    .env({"UV_PROJECT_ENVIRONMENT": "/usr/local"})
    .run_commands(
        [
            "uv sync --frozen --compile-bytecode",
            "uv build",
        ]
    )
)

# here's the error 
=> Step 2: RUN uv build
thread 'main' panicked at /home/runner/work/uv/uv/crates/uv/src/commands/build.rs:351:45:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Terminating task due to error: failed to run builder command "uv build"

Caused by:
    container exit status: 101
╭─ Error ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ Image build for im-WkUYKdIswH3MiW8mLDbyFN failed with the exception:                                                                                                                                                      │
│ task exited with failure, status = exit status: 1                                                                                                                                                                         │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

the fix was adding a workdir for modal's image container builder. not sure why.

image = (
    Image.debian_slim()
    .pip_install("uv")
    .workdir("/work") # <= work work work work work
    .copy_local_file("pyproject.toml", "/work/pyproject.toml")
    .copy_local_file("uv.lock", "/work/uv.lock")
    .env({"UV_PROJECT_ENVIRONMENT": "/usr/local"})
    .run_commands(
        [
            "uv sync --frozen --compile-bytecode",
            "uv build",
        ]
    )
)

if you'd like to view some of the example code I was using to test this, ive posted the example code here: https://github.com/anthonycorletti/modal-asgi-lifecycle-example/blob/main/app/_modal.py

not sure if this is recommended. lmk if im doing something incorrectly. thanks for all the work you do!

cc @thundergolfer

[charliermarsh]

We use the current working directory name there, but we can make it robust to that being empty -- it's just for logging / debugging. I'll fix it tomorrow.