From a18932c148a075d1e43fad1027745271f1d8a5f1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mil=C3=A1n=20B=C3=B3r?= <milanbor40@gmail.com>
Date: Tue, 5 Nov 2024 20:35:37 +0100
Subject: [PATCH] change(export_used_types): don't warn on behaviour callbacks

---
 src/elvis_style.erl                       | 13 ++++++++++++-
 test/examples/pass_export_used_types2.erl | 17 +++++++++++++++++
 test/style_SUITE.erl                      |  6 ++++--
 3 files changed, 33 insertions(+), 3 deletions(-)
 create mode 100644 test/examples/pass_export_used_types2.erl

diff --git a/src/elvis_style.erl b/src/elvis_style.erl
index efa6e197..bc73ffb7 100644
--- a/src/elvis_style.erl
+++ b/src/elvis_style.erl
@@ -1460,13 +1460,15 @@ always_shortcircuit(Config, Target, RuleConfig) ->
                            [elvis_result:item()].
 export_used_types(Config, Target, RuleConfig) ->
     TreeRootNode = get_root(Config, Target, RuleConfig),
+    IgnoredFunctions = get_behaviour_callbacks(TreeRootNode),
     ExportedFunctions = elvis_code:exported_functions(TreeRootNode),
+    FilteredExportedFunctions = lists:subtract(ExportedFunctions, IgnoredFunctions),
     ExportedTypes = elvis_code:exported_types(TreeRootNode),
     SpecNodes =
         elvis_code:find(fun is_spec_attribute/1, TreeRootNode, #{traverse => all, mode => node}),
     ExportedSpecs =
         lists:filter(fun(#{attrs := #{arity := Arity, name := Name}}) ->
-                        lists:member({Name, Arity}, ExportedFunctions)
+                        lists:member({Name, Arity}, FilteredExportedFunctions)
                      end,
                      SpecNodes),
     UsedTypes =
@@ -1492,6 +1494,15 @@ export_used_types(Config, Target, RuleConfig) ->
               end,
               UnexportedUsedTypes).
 
+get_behaviour_callbacks(Root) ->
+    IsBehaviour = fun(Node) -> ktn_code:type(Node) == behaviour end,
+    Behaviours = elvis_code:find(IsBehaviour, Root),
+    BehaviourNames = lists:map(fun(#{attrs := #{value := Behaviour}}) -> Behaviour end, Behaviours),
+
+    lists:append(
+      lists:map(fun(B) -> B:behaviour_info(callbacks) end, BehaviourNames
+    )).
+
 get_type_of_type(#{type := type_attr,
                    node_attrs := #{type := #{attrs := #{name := TypeOfType}}}}) ->
     TypeOfType;
diff --git a/test/examples/pass_export_used_types2.erl b/test/examples/pass_export_used_types2.erl
new file mode 100644
index 00000000..cf7afe72
--- /dev/null
+++ b/test/examples/pass_export_used_types2.erl
@@ -0,0 +1,17 @@
+-module(pass_export_used_types2).
+
+-behaviour(gen_server).
+
+-record(state, {a = field}).
+
+-type state() :: #state{}.
+
+-export([init/1, handle_cast/2, handle_call/3]).
+
+-spec init(_) -> {ok, state()}.
+init(_) -> {ok, #state{}}.
+
+handle_call(_, _, State) -> {State, ok, State}.
+
+-spec handle_cast(_, state()) -> {noreply, state()}.
+handle_cast(_, State) -> {noreply, State}.
diff --git a/test/style_SUITE.erl b/test/style_SUITE.erl
index d6aa6126..1a0ab141 100644
--- a/test/style_SUITE.erl
+++ b/test/style_SUITE.erl
@@ -753,8 +753,7 @@ verify_state_record_and_type_plus_export_used_types(Config) ->
         elvis_core_apply_rule(Config, elvis_style, export_used_types, #{}, PathPassGenStateM),
 
     PathFail = "fail_state_record_and_type_plus_export_used_types." ++ Ext,
-    [] = elvis_core_apply_rule(Config, elvis_style, state_record_and_type, #{}, PathFail),
-    [_] = elvis_core_apply_rule(Config, elvis_style, export_used_types, #{}, PathFail).
+    [] = elvis_core_apply_rule(Config, elvis_style, state_record_and_type, #{}, PathFail).
 
 -spec verify_behaviour_spelling(config()) -> any().
 verify_behaviour_spelling(Config) ->
@@ -1754,6 +1753,9 @@ verify_export_used_types(Config) ->
     PathPass = "pass_export_used_types." ++ Ext,
     [] = elvis_core_apply_rule(Config, elvis_style, export_used_types, #{}, PathPass),
 
+    PathPass2 = "pass_export_used_types2." ++ Ext,
+    [] = elvis_core_apply_rule(Config, elvis_style, export_used_types, #{}, PathPass2),
+
     PathFail = "fail_export_used_types." ++ Ext,
     [#{line_num := 3}] =
         elvis_core_apply_rule(Config, elvis_style, export_used_types, #{}, PathFail).