I am a long-lived wrapper around OTP's :xref cross-reference server.

The previous code in GtBridge.Analysis started a fresh :xref server, added the relevant app's ebin directory, ran one query, and stopped the server — for every call to function_references/3 and module_graph/1. The add_directory step is the expensive part; xref parses every .beam file in the directory to build its edge index. Doing that per-query made interactive paths (C-n, the |> expander) perceptibly slow.

I keep one xref server running for the lifetime of the BEAM. Indexing runs in a background :low-priority Task so it yields to any normal-priority work — eager add_directory on every loaded app contends with the OTP code server enough to cascade GT's startup module_details fan-out into 5s eval timeouts at normal priority. Queries arriving before indexing completes return {:ok, []} rather than blocking. When BeamModuleRecompiled fires (from hot_reload/2 via the event bus), I call :xref.replace_module/3 on just that module — so the index stays consistent with the live BEAM without rebuilding from scratch.

Public API

• q/1 — run an xref query string and return its :xref.q/2 result
• replace/1 — explicitly refresh one module's edges (also called automatically on BeamModuleRecompiled)

Subscriptions

I subscribe to GtBridge.Events.AnyModuleEvent and react to :recompiled events by calling replace/1 on the affected module.