BoundaryML/baml · error

compilation failed: {e:?}

Error message

compilation failed: {e:?}

What it means

In standalone `--file` mode, `baml pack` compiles the single BAML file with baml_compiler2_emit::generate_project_bytecode; if code generation (or compilation) returns an error, it is wrapped with anyhow! as `compilation failed: {e:?}`. This is the CLI's way of reporting that the file could not be turned into bytecode, distinct from diagnostics-level compile errors (which check_diagnostics reports first).

Source

Thrown at baml_language/crates/baml_cli/src/pack_command.rs:275

        }
        Ok(())
    }

    fn resolved_target_triple(&self) -> Result<&str> {
        match self.target_triple.as_deref() {
            Some(target) => validate_release_target_triple(target),
            None => release_host_target_triple(),
        }
    }

    fn load_and_compile(&self, reporter: &Reporter) -> Result<(ProjectDatabase, Program, bool)> {
        if let Some(file) = self.file.as_deref() {
            // Standalone `--file` mode has no project root, so there is no
            // cache seam — always a cold compile, same as `baml run --file`.
            let (db, package, needs_format_hint) = self.load_standalone(file)?;
            check_diagnostics(&db, "cannot pack: compilation errors found", reporter)?;
            let program = baml_compiler2_emit::generate_project_bytecode(&db, package)
                .map_err(|e| anyhow!("compilation failed: {e:?}"))?;
            return Ok((db, program, needs_format_hint));
        }
        self.load_and_compile_project(reporter)
    }

    /// Project-mode load + compile through the bytecode cache — the same warm
    /// flow as `baml run` (`run_command::load_and_compile`): whole-program hit
    /// when nothing changed, per-file unit reuse on a dirty edit, full compile
    /// otherwise. Pack shares run/check's exact cache key space, so a pack
    /// right after a run (or a
    /// re-pack) serves the identical `Program`. The packaged bytecode is
    /// target-independent (the `--target` triple only selects the host binary
    /// bytes), and emit determinism guarantees a reused image is byte-identical
    /// to a fresh compile, so serving from cache never changes the artifact.
    fn load_and_compile_project(
        &self,
        reporter: &Reporter,
    ) -> Result<(ProjectDatabase, Program, bool)> {

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Read the wrapped `{e:?}` detail to identify the failing construct and simplify or fix it in the source file.
2. Fix any diagnostics first with `baml check --file <path>` to rule out ordinary compile errors.
3. Update the baml CLI/compiler to matching latest versions and retry.
4. If the source looks valid, file a bug with the debug-formatted error and a minimal repro file.

Example fix

// before
baml pack --file broken.baml   // compilation failed: <codegen error>

// after: check first, fix the reported construct, then pack
baml check --file broken.baml
baml pack --file broken.baml

# run a check-only compile first
baml check --file path/to/file.baml

match baml_pack_standalone(file) {
    Err(e) if e.to_string().starts_with("compilation failed") => {
        eprintln!("codegen failed: {e:#}");
        // report bug or adjust source
    }
    Err(e) => return Err(e),
    Ok(out) => /* proceed */ (),
}

When it happens

Trigger: Running `baml pack --file <path>` where the file parses cleanly enough to pass check_diagnostics but generate_project_bytecode still fails (e.g. internal codegen errors on constructs it cannot lower).

Common situations: Packing a standalone .baml file that uses a feature the bytecode emitter does not yet support; a compiler bug triggered by unusual code; version mismatch between CLI and compiler crates in a local build.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• compilation failed: {e:?}
• failed to generate Go SDK: {error}
• positional `<TARGET>` and `-f/--function` are mutually exclu
• no target specified. Pass a positional `<TARGET>` to pack on
• no `.baml` files found in {}

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/a1a879eb77d5eff8. Report an issue: GitHub.