AlexsJones/llmfit · info

OUT_DIR

Error message

OUT_DIR

What it means

The same build.rs reads OUT_DIR (the scratch directory cargo creates per compiled crate) to know where to write the generated web_assets.rs that embeds the dashboard. Cargo guarantees OUT_DIR for build script execution, so this .expect, like the CARGO_MANIFEST_DIR one, only fires when build.rs runs outside the cargo build environment.

Source

Thrown at llmfit-tui/build.rs:12

use std::env;
use std::fs;
use std::path::{Path, PathBuf};

fn main() {
    println!("cargo:rerun-if-changed=build.rs");

    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR"));
    let dist_dir = manifest_dir.join("..").join("llmfit-web").join("dist");
    println!("cargo:rerun-if-changed={}", dist_dir.display());

    let out_dir = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR"));
    let out_file = out_dir.join("web_assets.rs");

    let generated = if dist_dir.exists() {
        let mut files = Vec::new();
        collect_files(&dist_dir, &mut files);
        files.sort();
        for file in &files {
            println!("cargo:rerun-if-changed={}", file.display());
        }
        generate_assets_from_dist(&dist_dir, &files)
    } else {
        println!(
            "cargo:warning=llmfit-web/dist not found. Falling back to placeholder embedded dashboard. Run `npm ci && npm run build` in llmfit-web."
        );
        generate_fallback_assets()
    };

    fs::write(&out_file, generated).expect("failed to write generated web_assets.rs");

View on GitHub (pinned to acc7e40c3a)

Solutions

1. Build via cargo: `cargo build -p llmfit` — OUT_DIR is provided automatically
2. For manual runs, set both CARGO_MANIFEST_DIR and OUT_DIR to writable directories (e.g. under /tmp) before executing the script
3. If you need the generated file for inspection, look under target/debug/build/llmfit-*/out/web_assets.rs after a cargo build instead

Example fix

# before
./target/debug/build/llmfit-*/build-script-main  # panics: OUT_DIR

# after
cargo build -p llmfit
cat target/debug/build/llmfit-*/out/web_assets.rs

// Only relevant if executing build.rs outside cargo:
let out_dir = std::env::var("OUT_DIR")
    .expect("run me via `cargo build`, or export OUT_DIR to a writable dir");
assert!(std::path::Path::new(&out_dir).is_dir(), "OUT_DIR must exist and be writable");

When it happens

Trigger: Directly invoking the compiled build script (`./libllmfit_build-script.out`) without env; a debugging harness that runs build.rs with a partially copied environment; cargo-external integration that forgets OUT_DIR.

Common situations: Build-script debugging sessions; custom build pipelines that try to pre-generate web_assets.rs by hand.

Understand the failure class

Background: "environment variable is not set" and "Missing keys in environment" errors: what missing required env var messages mean and how to fix them — this error's family across 28 libraries.

Related errors

• CARGO_MANIFEST_DIR
• failed to write generated web_assets.rs
• invalid dir entry
• valid MLX suffix regex
• Binary not found at {bin_path}. Expected it to be built for

AI-assisted analysis of AlexsJones/llmfit@acc7e40c3a (2026-08-17). Data as JSON: /api/errors/9af5f4b7657587de. Report an issue: GitHub.