Add compile time errors reporting (#3)

Co-authored-by: Sergei Shuvatov <rconv@odem.su>

.github/workflows/erlang.yml

@@ -23,4 +23,4 @@ jobs:
     - name: Compile
       run: rebar3 compile
     - name: Run tests
-      run: rebar3 as test do xref, dialyzer, eunit
+      run: rebar3 as test do xref, dialyzer, eunit -c, ct -c, cover -v

README.md

@@ -9,7 +9,7 @@ Usage
 Add dependency to your rebar.config
 ```erlang
     {deps, [
-        {rconv, {git, "git@github.com:Yozhig/rconv.git", {tag, "0.1.0"}}},
+        {rconv, {git, "https://github.com/Yozhig/rconv.git", {tag, "0.1.0"}}},
     ]}
 ```
 and compile option for parse transform at the top of the source file

rebar.config

@@ -14,12 +14,17 @@
         unknown
     ]},
     {plt_apps, all_deps},
-    {plt_extra_apps, [eunit]}
+    {plt_extra_apps, [common_test, compiler, eunit]}
 ]}.
 
 {xref_ignores, [
     {rconv, to_map, 2},
     {rconv, to_clean_map, 3},
     {rconv, from_map, 2},
-    {rconv, parse_transform, 2}
+    {rconv, parse_transform, 2},
+    {rconv, format_error, 1}
+]}.
+
+{eunit_tests, [
+    {module, rconv_test}
 ]}.

src/rconv.erl

@@ -6,21 +6,12 @@
     from_map/2
 ]).
 
--export([parse_transform/2]).
-
--type record_name() :: atom().
--type field_name() :: atom().
-% type of a default value may differ from declared field type
-% we only need to know the type of a default value to properly construct a record
--type default_value_type() :: atom().
--type default_value() :: term().
+-export([
+    parse_transform/2,
+    format_error/1
+]).
 
--record(state, {
-    records = #{} :: #{record_name() => [{field_name(), default_value_type(), default_value()}]}
-}).
-
-% -define(log(F, A), io:format(standard_error, "~n=======~n" F "~n=======~n", A)).
--define(log(F, A), ok).
+%% API stubs
 
 %% @doc Constructs a map from a provided record.
 -spec to_map(tuple(), atom()) -> map().
@@ -43,10 +34,40 @@ to_clean_map(_Record, _RecordName, _FilterFun) ->
 from_map(_Map, _RecordName) ->
     erlang:nif_error(<<"Add `-compile([{parse_transform, rconv}]).` to your module">>).
 
+%%     _____                    __
+%%    |_   _|                  / _|
+%%      | |_ __ __ _ _ __  ___| |_ ___  _ __ _ __ ___
+%%      | | '__/ _` | '_ \/ __|  _/ _ \| '__| '_ ` _ \
+%%      | | | | (_| | | | \__ \ || (_) | |  | | | | | |
+%%      \_/_|  \__,_|_| |_|___/_| \___/|_|  |_| |_| |_|
+%%
+
+-type record_name() :: atom().
+-type field_name() :: atom().
+% type of a default value may differ from declared field type
+% we only need to know the type of a default value to properly construct a record
+-type default_value_type() :: atom().
+-type default_value() :: term().
+
+-record(state, {
+    records = #{} :: #{record_name() => [{field_name(), default_value_type(), default_value()}]},
+    errors = [] :: [{error, erl_parse:error_info()}]
+}).
+
+% -define(log(F, A), io:format(standard_error, "~n=======~n" F "~n=======~n", A)).
+-define(log(F, A), ok).
+
 parse_transform(Ast, _Opts) ->
-    % ?log("Ast: ~n~p", [Ast]),
-    {NewAst, _} = traverse(fun search_and_replace/2, #state{}, Ast),
-    NewAst.
+    ?log("Ast: ~n~p", [Ast]),
+    {NewAst, #state{errors = Errors}} = traverse(fun search_and_replace/2, #state{}, Ast),
+    Errors ++ NewAst.
+
+format_error({record_not_found, RecName}) ->
+    io_lib:format("record '~p' not found", [RecName]);
+format_error(bad_record_name) ->
+    "record name argument should be an atom".
+
+%% Internals
 
 traverse(Fun, State, List) when is_list(List) ->
     lists:mapfoldl(
@@ -75,14 +96,11 @@ search_and_replace(
 search_and_replace( % map construction
     {call, Loc,
         {remote, _, {atom, _, ?MODULE}, {atom, _, to_map}},
-        [RecVal, {atom, _, RecName}]} = Node,
-    #state{records = Records} = St
+        [RecVal, RecNameArg]} = AsIs,
+    State
 ) ->
-    case maps:get(RecName, Records, undefined) of
-        undefined -> % FIXME: emit error at compile time
-            ?log("WARNING: ~p not found", [RecName]),
-            {Node, St};
-        Fields ->
+    case check_record(Loc, RecNameArg, State) of
+        {ok, RecName, Fields} ->
             MapFields = [
                 {map_field_assoc,
                     Loc,
@@ -95,37 +113,34 @@ search_and_replace( % map construction
                 || {F, _Type, _DefValue} <- Fields
             ],
             MapExpr = {map, Loc, MapFields},
-            {MapExpr, St}
+            {MapExpr, State};
+        {error, NewState} ->
+            {AsIs, NewState}
     end;
 search_and_replace( % clean (filtered) map
     {call, Loc,
         {remote, _, {atom, _, ?MODULE}, {atom, _, to_clean_map}},
-        [RecVal, RecNameAtom, FilterFun]} = Node,
-    #state{records = Records} = St
+        [RecVal, RecNameArg, FilterFun]} = AsIs,
+    State
 ) ->
-    {atom, _, RecName} = RecNameAtom,
-    case maps:get(RecName, Records, undefined) of
-        undefined -> % FIXME: emit error at compile time
-            ?log("WARNING: ~p not found", [RecName]),
-            {Node, St};
-        Fields ->
+    case check_record(Loc, RecNameArg, State) of
+        {ok, RecName, Fields} ->
             MapFromList =
                 {call, Loc,
                     {remote, Loc, {atom, Loc, maps}, {atom, Loc, from_list}},
                     [plus(Fields, RecVal, RecName, Loc, FilterFun)]},
-            {MapFromList, St}
+            {MapFromList, State};
+        {error, NewState} ->
+            {AsIs, NewState}
     end;
 search_and_replace( % record construction
     {call, Loc,
         {remote, _, {atom, _, ?MODULE}, {atom, _, from_map}},
-        [MapVal, {atom, _, RecName}]} = Node,
-    #state{records = Records} = St
+        [MapVal, RecNameArg]} = AsIs,
+    State
 ) ->
-    case maps:get(RecName, Records, undefined) of
-        undefined -> % FIXME: emit error at compile time
-            ?log("WARNING: ~p not found", [RecName]),
-            {Node, St};
-        Fields ->
+    case check_record(Loc, RecNameArg, State) of
+        {ok, RecName, Fields} ->
             RecordFields = [
                 {record_field,
                     Loc,
@@ -138,7 +153,9 @@ search_and_replace( % record construction
                 || {F, Type, DefValue} <- Fields
             ],
             RecordExpr = {record, Loc, RecName, RecordFields},
-            {RecordExpr, St}
+            {RecordExpr, State};
+        {error, NewState} ->
+            {AsIs, NewState}
     end;
 search_and_replace(Node, St) ->
     {Node, St}.
@@ -169,3 +186,21 @@ lc({FieldName, _Type, _DefValue}, RecVal, RecName, Loc, FilterFun) ->
             {record_field, Loc, RecVal, RecName, {atom, Loc, FieldName}}
         ]}]
     }.
+
+check_record(_Loc, {atom, RecNameLoc, RecName}, #state{records = Records} = St) ->
+    case maps:get(RecName, Records, undefined) of
+        undefined ->
+            {error, not_found(RecName, RecNameLoc, St)};
+        Fields ->
+            {ok, RecName, Fields}
+    end;
+check_record(Loc, _, St) ->
+    {error, bad_record_name(Loc, St)}.
+
+not_found(RecName, Loc, #state{errors = Errors} = St) ->
+    Error = {error, {Loc, ?MODULE, {record_not_found, RecName}}},
+    St#state{errors = [Error | Errors]}.
+
+bad_record_name(Loc, #state{errors = Errors} = St) ->
+    Error = {error, {Loc, ?MODULE, bad_record_name}},
+    St#state{errors = [Error | Errors]}.

test/compile_time_errors_SUITE.erl

@@ -0,0 +1,63 @@
+-module(compile_time_errors_SUITE).
+
+-include_lib("stdlib/include/assert.hrl").
+
+-behaviour(ct_suite).
+-export([
+    all/0
+]).
+
+%% Tests
+-export([
+    norecord/1,
+    format_error/1,
+    success/1
+]).
+
+%% ct_suite callbacks
+
+all() ->
+    [
+        norecord,
+        format_error,
+        success
+    ].
+
+%% Tests
+
+norecord(Config) ->
+    DataDir = proplists:get_value(data_dir, Config),
+    File = filename:join(DataDir, "norecord"),
+    ?assertEqual(
+        {
+            error,
+            [
+                {File ++ ".erl", [
+                    {{15, 23}, rconv, {record_not_found, norecord}},
+                    {{18, 5}, rconv, bad_record_name},
+                    {{22, 29}, rconv, {record_not_found, another_absent_record}},
+                    {{25, 25}, rconv, {record_not_found, norecord}}
+                ]}
+            ],
+            []
+        },
+        compile:file(File, [return])
+    ).
+
+format_error(_Config) ->
+    ?assertEqual(
+        "record 'norecord' not found",
+        lists:flatten(rconv:format_error({record_not_found, norecord}))
+    ),
+    ?assertEqual(
+        "record name argument should be an atom",
+        lists:flatten(rconv:format_error(bad_record_name))
+    ).
+
+success(Config) ->
+    DataDir = proplists:get_value(data_dir, Config),
+    File = filename:join(DataDir, "success"),
+    ?assertEqual(
+        {ok, success, []},
+        compile:file(File, [return])
+    ).

test/compile_time_errors_SUITE_data/norecord.erl

@@ -0,0 +1,25 @@
+%%% This module must not compile and parse transform should emit errors at compile time
+
+-module(norecord).
+
+-compile([{parse_transform, rconv}]).
+
+-export([
+    to_map/1,
+    to_map_bad_arg/1,
+    to_clean_map/1,
+    from_map/1
+]).
+
+to_map(Rec) ->
+    rconv:to_map(Rec, norecord).
+
+to_map_bad_arg(Rec) ->
+    rconv:to_map(Rec, []).
+
+to_clean_map(Rec) ->
+    Filter = fun(V) -> V /= undefined end,
+    rconv:to_clean_map(Rec, another_absent_record, Filter).
+
+from_map(Map) ->
+    rconv:from_map(Map, norecord).

test/compile_time_errors_SUITE_data/success.erl

@@ -0,0 +1,32 @@
+-module(success).
+
+-compile([{parse_transform, rconv}]).
+
+-export([
+    to_map/1,
+    to_clean_map/1,
+    empty_to_clean_map/1,
+    from_map/1
+]).
+
+-record(success, {
+    a :: term(),
+    b = false,
+    c
+}).
+
+-record(empty, {}).
+
+to_map(R) ->
+    rconv:to_map(R, success).
+
+to_clean_map(R) ->
+    Filter = fun(V) -> V /= undefined end,
+    rconv:to_clean_map(R, success, Filter).
+
+empty_to_clean_map(#empty{} = _E) ->
+    % just a strange corner case, not an example
+    rconv:to_clean_map(_E, empty, fun(_) -> true end).
+
+from_map(M) ->
+    rconv:from_map(M, success).