BoundaryML/baml · error

compilation failed: {e:?}

Error message

compilation failed: {e:?}

What it means

During `baml generate`, after building the compiler database and symbol pool, the CLI fetches the compiled program bytecode via `db.get_bytecode(package)`. If the compiler produces any diagnostics/errors, they are formatted with `{e:?}` and wrapped in this "compilation failed" anyhow error.

Source

Thrown at baml_language/crates/baml_cli/src/generate.rs:350

                eprintln!("add a generator section to `baml.toml`, for example:");
                eprintln!();
                eprintln!("  [generator.my_client]");
                eprintln!("  output_type = \"python/pydantic\"");
                eprintln!("  output_dir = \"../python\"");
                eprintln!("  naming_convention = \"preserve-case\"");
            }
            return Ok(crate::ExitCode::Other);
        }

        let embedded_baml_toml = build_embedded_baml_toml(&from)?;

        // Build the codegen SymbolPool from the compiler database.
        let pool = baml_ide::build_symbol_pool(&db);

        reporter.spin("Compiling", format!("{} file(s)", source_files.len()));
        let program = db
            .get_bytecode(package)
            .map_err(|e| anyhow!("compilation failed: {e:?}"))?;
        let baml_bytecode = baml_artifact::encode(baml_artifact::ArtifactKind::Program, &program)
            .map_err(|e| anyhow!("failed to serialize BAML bytecode: {e}"))?;
        let source_root = from.join("baml_src");
        let user_baml_files = source_files
            .iter()
            .map(|source_file| {
                let path = source_file.path(&db);
                let relative_path = path
                    .strip_prefix(&source_root)
                    .or_else(|_| path.strip_prefix(&from))
                    .with_context(|| {
                        format!(
                            "BAML source {} is outside project root {}",
                            path.display(),
                            from.display()
                        )
                    })?;
                Ok((

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Read the detailed diagnostics after 'compilation failed:' and fix the reported BAML errors.
2. Run `baml-cli fmt` / open the file in an editor with BAML LSP to locate the offending lines.
3. Verify your generator block and clients in baml_src compile (e.g. via the VS Code BAML extension's diagnostics).
4. Update the CLI if the errors mention unsupported syntax/features (version mismatch).

Example fix

// before (baml_src/generator.baml)
generator ClientGenerator { ... provider "baml-openai" }  // typo'd provider
// after
generator ClientGenerator { ... provider "openai" }

match baml_generate() {
  Err(e) if e.to_string().starts_with("compilation failed") => {
    eprintln!("Fix BAML diagnostics before generating: {e:#}");
    std::process::exit(1);
  }
  Err(e) => return Err(e),
  Ok(_) => {}
}

When it happens

Trigger: `baml generate` on a project whose baml_src contains BAML source that does not compile — syntax errors, type errors, unresolved functions/clients, invalid generator config in baml.toml.

Common situations: A recent edit to a .baml file introduced an error; a generator block references a missing client; baml.toml and baml_src are out of sync; using new language features with an older CLI.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• {bail_context}
• compilation failed: {e:?}
• compilation failed: {e:?}
• no `.baml` files found in {}
• could not find packaged playground assets. For local debuggi

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/5c91301923cdc73d. Report an issue: GitHub.