[Fix #468] Add include_dirs/1 to elvis_config

README.md

@@ -103,6 +103,7 @@ in the root directory:
    [
     {config,
      [#{dirs => ["src"],
+        include_dirs => ["include"],
         filter => "*.erl",
         ruleset => erl_files
        },
@@ -130,6 +131,9 @@ in the root directory:
 ].
 ```
 
+The `include_dirs` key is just a list of folders (`[string()]`) where to search for
+header files.
+
 The `dirs` key is a list that indicates where `elvis` should look for the
 files that match `filter`, which will be run through each of the default rules
 in the specified `ruleset`, which is an *atom*. If you want to override the

src/elvis_config.erl

@@ -8,6 +8,7 @@
          normalize/1,
          %% Geters
          dirs/1,
+         include_dirs/1,
          ignore/1,
          filter/1,
          files/1,
@@ -27,6 +28,7 @@
 -define(DEFAULT_CONFIG_PATH, "./elvis.config").
 -define(DEFAULT_REBAR_CONFIG_PATH, "./rebar.config").
 -define(DEFAULT_FILTER, "*.erl").
+-define(DEFAULT_INCLUDE_DIRS, ["include"]).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Public
@@ -116,6 +118,15 @@ dirs(_RuleGroup = #{dirs := Dirs}) ->
 dirs(#{}) ->
     [].
 
+% Only get `include_dirs' value for erl files RuleGroup, discard other ones.
+-spec include_dirs(Config::config() | map()) -> [string()].
+include_dirs(Config) when is_list(Config) ->
+    lists:flatmap(fun include_dirs/1, Config);
+include_dirs(_RuleGroup = #{include_dirs := IDirs})->
+    IDirs;
+include_dirs(_) ->
+    ?DEFAULT_INCLUDE_DIRS.
+
 -spec ignore(config() | map()) -> [string()].
 ignore(Config) when is_list(Config) ->
     lists:flatmap(fun ignore/1, Config);