is not a directory (expected a directory containing BAML…

Error message

{dir:#?} is not a directory (expected a directory containing BAML files)

What it means

As a final shape check, baml_src_files() requires the path to actually be a directory (dir.is_dir()). This branch handles exotic cases where a path exists, is not a file, but is also not a directory — e.g. special files, sockets, FIFOs, or device nodes. It ensures the walker below only ever runs against a real directory.

Solutions

Remove the special file at that path and restore a real baml_src directory (`mkdir baml_src` and restore your .baml files)
Check where the path points with `ls -la` / `stat baml_src` and fix the symlink or mount
Correct the configured baml_src path if it points at a runtime artifact (socket/pipe) instead of the source folder

Example fix

// before (path is a socket/fifo)
$ stat baml_src  # Type: socket

// after
$ rm baml_src
$ mkdir baml_src && mv *.baml baml_src/

Defensive patterns

Strategy: validation

Validate before calling

import fs from 'fs';
const st = fs.lstatSync(dir);
if (!st.isDirectory()) throw new Error(`${dir} exists but is not a regular directory (${st.mode}); fix symlinks/mounts`);

Try / catch

try {
  bamlSrcFiles(dir);
} catch (e) {
  if (/is not a directory/i.test(e.message)) {
    console.error(`${dir} is a special file/socket/broken symlink; restore a real directory there`);
  }
  throw e;
}

Prevention

Use ls -la / stat to inspect the baml_src path if it behaves oddly
Avoid bind-mounting sockets or devices into your source tree
Restore directories after failed container volume mounts

When it happens

Trigger: Calling baml_src_files with a path that exists but is neither a file nor a directory: a Unix socket, FIFO, symlink to a special file, or device node at the baml_src location.

Common situations: Rare in practice: a broken symlink resolution creating a special file where baml_src/ should be; a bind-mount or container volume mapping a socket/device to that path; corrupted build outputs.

Related errors

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/e23f06054ed8f82c. Report an issue: GitHub.

Appendix: source

Thrown at engine/baml-runtime/src/lib.rs:2252

    }
}

#[cfg(not(target_arch = "wasm32"))]
pub fn baml_src_files(dir: &std::path::PathBuf) -> Result<Vec<PathBuf>> {
    static VALID_EXTENSIONS: [&str; 1] = ["baml"];

    log::trace!("Reading files from {:#}", dir.to_string_lossy());

    if !dir.exists() {
        anyhow::bail!("{dir:#?} does not exist (expected a directory containing BAML files)",);
    }
    if dir.is_file() {
        return Err(anyhow::anyhow!(
            "{dir:#?} is a file, not a directory (expected a directory containing BAML files)",
        ));
    }
    if !dir.is_dir() {
        return Err(anyhow::anyhow!(
            "{dir:#?} is not a directory (expected a directory containing BAML files)",
        ));
    }

    let src_files = walkdir::WalkDir::new(dir)
        .into_iter()
        .filter_map(|e| match e {
            Ok(e) => Some(e),
            Err(e) => {
                log::error!("Error while reading files from {dir:#?}: {e}");
                None
            }
        })
        .filter(|e| e.file_type().is_file())
        .filter(|e| {
            let Some(ext) = e.path().extension() else {
                return false;
            };

View on GitHub (pinned to bd85ce9dee)