BoundaryML/baml · error

Failed to update runtime after reloading files: {e}

Error message

Failed to update runtime after reloading files: {e}

What it means

After reload reloads files, it rebuilds each project's runtime; a failure updating the runtime (e.g. errors compiling the BAML schema into a runtime) is logged via tracing::error! and surfaced as 'Failed to update runtime after reloading files'. It indicates the reloaded sources are inconsistent or invalid for runtime construction.

Source

Thrown at engine/language_server/src/session.rs:273

                tracing::info!(
                    "Loaded {} files for project root: {:?}",
                    files_map.len(),
                    project_root
                );

                {
                    let default_flags = vec!["beta".to_string()];
                    project.lock().update_runtime(
                        notifier.clone(),
                        self.baml_settings
                            .feature_flags
                            .as_ref()
                            .unwrap_or(&default_flags),
                    )
                }
                .map_err(|e| {
                    tracing::error!("Failed to update runtime after reloading files: {e}");
                    anyhow::anyhow!("Failed to update runtime after reloading files: {e}")
                })?;
                Ok(files_map)
            })
            .collect::<anyhow::Result<Vec<_>>>()?;

        let total_files: usize = project_updates.iter().map(|m| m.len()).sum();
        tracing::info!(
            "Initial reload complete: {} projects, {} total files",
            project_updates.len(),
            total_files
        );

        // Guard no longer used. We can drop now instead of waiting for the end
        // of scope.
        drop(baml_src_projects);

        let files: Vec<(DocumentKey, String)> = project_updates
            .into_iter()

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Read the inner error to find the offending BAML file/diagnostic
2. Fix the BAML syntax/type errors in the reloaded sources
3. Check baml_settings.feature_flags match the current schema version
4. Retry the reload (or restart the server) once sources are valid

Example fix

// before: broken baml on disk
function Foo { prompt #"..." } // malformed
// after: valid definition
function Foo() -> string { client GPT4o prompt #"hi" }

// validate baml files compile (e.g. via CLI) before reload
$ baml-cli validate ./baml_src

try { await triggerReload(); } catch (e) { if (String(e).includes('update runtime')) { showDiagnostics(e.cause); /* fix sources, then */ await triggerReload(); } else throw e; }

When it happens

Trigger: load_files succeeded but update_runtime fails: BAML source with syntax/type errors introduced on disk, inconsistent partial file states mid-reload, or feature-flag configuration incompatible with the new sources.

Common situations: Saving a broken .baml file while the LSP watches the directory; git branch switch leaving transiently invalid sources; feature_flags in settings that no longer match the reloaded schema.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• Failed to load project files: {}
• Could not update runtime: {e}
• {0}
• Notification not supported: {0}
• Request not supported: {0}

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/e1705cdbff4ab468. Report an issue: GitHub.