Pact Go verifier provider mismatch / setup error in CI

pact-go drives verification through the shared FFI library and reports failures from VerifyProvider. Failures are either genuine interaction mismatches or setup problems: a missing libpact_ffi shared library or a provider base URL that is not reachable.

What this error means

A Go test fails with "the verification process failed" from VerifyProvider, or the binary cannot load libpact_ffi, so verification never runs.

Pact Go

--- FAIL: TestProvider (0.42s)
    verifier.go: the verification process failed, see output for details
    error while loading shared libraries: libpact_ffi.so: cannot open shared object file

Common causes

The Pact FFI shared library is not installed

pact-go needs the libpact_ffi library available at the expected version; a missing or mismatched library stops verification before it starts.

Interaction mismatch or unreachable provider

The provider response did not match a pact, or ProviderBaseURL pointed at a provider that was not running.

How to fix it

Install the matching FFI library

Run pact-go installer to fetch the FFI library version the client expects.
Confirm the library is on the loader path.
Re-run verification.

Terminal

go install github.com/pact-foundation/pact-go/v2@latest
pact-go -l DEBUG install

Point at a running provider and set state handlers

Set ProviderBaseURL to the booted app and register StateHandlers for each provider state.

provider_test.go

verifier.VerifyProvider(t, provider.VerifyRequest{
  ProviderBaseURL: "http://localhost:8080",
  StateHandlers:   handlers,
})

How to prevent it

Install the pact-go FFI library as a setup step in CI.
Health-check the provider before VerifyProvider runs.
Register state handlers for every provider state.