Bug with Hammox when upgrading Elixir

[epinault]

Hello,

I am upgrading from elixir 1.15 to 1.16.3, OTP version is the same 26.2.5

yet test that were passing in 1.15 are now failing with this error.

any idea what the issue might be?

** (FunctionClauseError) no function clause matching in Hammox.TypeEngine.match_type/2

 The following arguments were given to Hammox.TypeEngine.match_type/2:

     # 1
     %{}

     # 2
     {:type, {87, 25}, :record, [{:atom, {87, 26}, :set}, {:type, {87, 30}, :field_type, [{:atom, {87, 30}, :segs}, {:remote_type, 0, [{:atom, 0, :sets}, {:atom, 0, :segs}, [{:type, {57, 16}, :term, []}]]}]}]}

 Attempted function clauses (showing 10 out of 93):

     def match_type(value, {:type, _, :union, union_types} = union) when is_list(union_types)
     def match_type(_value, {:type, _, :any, []})
     def match_type(value, {:type, _, :none, []} = type)
     def match_type(value, {:type, _, :atom, []}) when is_atom(value)
     def match_type(value, {:type, _, :atom, []} = type)
     def match_type(value, {:type, _, :map, :any}) when is_map(value)
     def match_type(value, {:type, _, :pid, []}) when is_pid(value)
     def match_type(value, {:type, _, :pid, []} = type)
     def match_type(value, {:type, _, :port, []}) when is_port(value)
     def match_type(value, {:type, _, :port, []} = type)
     ...
     (83 clauses not shown)

[kerryb]

I’m getting pretty much the same error (Hammox 0.7.0, Erlang 27.0, Elixir 1.17.2-otp-27). I’m trying to retrofit Hammox to a project that currently uses Mox, so I don’t know whether it would have passed on older versions.

     ** (FunctionClauseError) no function clause matching in Hammox.TypeEngine.match_type/2

     The following arguments were given to Hammox.TypeEngine.match_type/2:

         # 1
         %{}

         # 2
         {:type, {163, 25}, :record, [{:atom, {163, 26}, :set}, {:type, {163, 30}, :field_type, [{:atom, {163, 30}, :segs}, {:remote_type, 0, [{:atom, 0, :sets}, {:atom, 0, :segs}, [{:remote_type, {62, 46}, [{:atom, 0, String}, {:atom, 0, :t}, []]}]]}]}]}

     Attempted function clauses (showing 10 out of 93):

         def match_type(value, {:type, _, :union, union_types} = union) when is_list(union_types)
         def match_type(_value, {:type, _, :any, []})
         def match_type(value, {:type, _, :none, []} = type)
         def match_type(value, {:type, _, :atom, []}) when is_atom(value)
         def match_type(value, {:type, _, :atom, []} = type)
         def match_type(value, {:type, _, :map, :any}) when is_map(value)
         def match_type(value, {:type, _, :pid, []}) when is_pid(value)
         def match_type(value, {:type, _, :pid, []} = type)
         def match_type(value, {:type, _, :port, []}) when is_port(value)
         def match_type(value, {:type, _, :port, []} = type)
         ...
         (83 clauses not shown)

It looks like Hammox is trying to check a record type, which it doesn’t support. I think this may be an issue with typespecs that use MapSet.t(), as MapSet is built on top of Erlang’s :sets, which in turn are defined as records.

[kerryb]

I’ve added a specific issue for MapSet support (I don’t know how big an enhancement it would be). I’m not sure that’s exactly the same problem you have, but hopefully it’ll help narrow things down slightly.