If I understand correctly: •

pact_ffi

advertises that it will accept

"pact:generator:type": "ProviderState"

. • Pact specification mentions that the

ProviderState

generator is expressed like

{type": "ProviderState", "expression": "/api/user/${id}"}

Is it then safe to assume that a potentially new

FromProviderState

matcher, used in the context

...
        .withResponseJsonBody( Object( {
                { "assetId",      FromProviderState( "${id}, "someAssetId" ) },
...

should generate

{ "value": "someAssetId, "pact:generator:type": "ProviderState", "expression": "${id}" }

? Should there be a

type

matcher inserted as well? I can see for example that in

pact-js

, the

fromProviderState

method "Sets a type matcher and a provider state generator." I.e.:

{ "value": "someAssetId, "pact:matcher:type":"type", "pact:generator:type": "ProviderState", "expression": "${id}" }

You’re right, the

ProviderState

generator is not a matcher, so if you need it to also constrain the types, you need to combine matching rules: https://docs.pact.io/implementation_guides/rust/pact_ffi/integrationjson#supporting-multiple-matching-rules