Enable regex for directory directives (#1452)

* Enable regex for directory directives

The code was already ready for that but escaped the potential regexp declared in
the reek configuration, actually disabling regexp.

This commit fixes this by removing the call to escape.

This allows this kind of declaration in the configuration file:

```yaml
---
[...]
  "engines/.*/test/.*":
    InstanceVariableAssumption:
      enabled: false
    UncommunicativeVariableName:
      enabled: false
```

* Support glob like syntax for directory patterns

This is a mix of currently supported patterns and `glob` patterns.

Currently supported patterns assumes that declared directories includes
sub-directories as well.

`glob` like patterns act like Dir.glob, but are actually backed by a
Regexp, this may lead to some different behaviour.

* Add documentation about Dir.glob pattern for `directory` directives

* Escape . characters

This make sure that the directive does not match an arbitrary character
that is not a `.`.

* Fix code alignment

README.md

@@ -309,12 +309,18 @@ detectors:
 # You can configure smells on a per-directory base.
 # E.g. the classic Rails case: controllers smell of NestedIterators (see /docs/Nested-Iterators.md) and
 # helpers smell of UtilityFunction (see docs/Utility-Function.md)
-# Note that we only allow configuration on a directory level, not a file level, so all paths have to point to directories.
+#
+# Note that we only allow configuration on a directory level, not a file level,
+# so all paths have to point to directories.
+# A Dir.glob pattern can be used.
 directories:
   "web_app/app/controllers":
     NestedIterators:
       enabled: false
-  "web_app/app/helpers":
+  "web_app/app/helpers**:
+    UtilityFunction:
+      enabled: false
+  "web_app/lib/**/test/**":
     UtilityFunction:
       enabled: false
 

lib/reek/configuration/directory_directives.rb

@@ -53,10 +53,37 @@ def add(directory_config)
       # @quality :reek:FeatureEnvy
       def best_match_for(source_base_dir)
         keys.
-          select { |pathname| source_base_dir.to_s.match(/#{Regexp.escape(pathname.to_s)}/) }.
+          select { |pathname| source_base_dir.to_s.match(glob_to_regexp(pathname.to_s)) }.
           max_by { |pathname| pathname.to_s.length }
       end
 
+      # Transform a glob pattern to a regexp.
+      #
+      # It changes:
+      # - /** to .*,
+      # - ** to .*,
+      # - * to [^\/]*.
+      #
+      # @quality :reek:FeatureEnvy
+      # @quality :reek:UtilityFunction
+      def glob_to_regexp(glob)
+        is_glob_pattern = glob.include?('*')
+
+        regexp = if is_glob_pattern
+                   glob.
+                     gsub(%r{/\*\*$}, '<<to_eol_wildcards>>').
+                     gsub('**', '<<to_wildcards>>').
+                     gsub('*', '[^/]*').
+                     gsub('.', '\.').
+                     gsub('<<to_eol_wildcards>>', '.*').
+                     gsub('<<to_wildcards>>', '.*')
+                 else
+                   glob + '.*'
+                 end
+
+        Regexp.new("^#{regexp}$", Regexp::IGNORECASE)
+      end
+
       def error_message_for_invalid_smell_type(klass)
         "You are trying to configure smell type #{klass} but we can't find one with that name.\n" \
           "Please make sure you spelled it right. (See 'docs/defaults.reek' in the Reek\n" \

spec/reek/configuration/directory_directives_spec.rb

@@ -44,9 +44,12 @@
   describe '#best_match_for' do
     let(:directives) do
       {
-        Pathname.new('foo/bar/baz') => {},
-        Pathname.new('foo/bar')     => {},
-        Pathname.new('bar/boo')     => {}
+        Pathname.new('foo/bar/baz')    => {},
+        Pathname.new('foo/bar')        => {},
+        Pathname.new('bar/boo')        => {},
+        Pathname.new('bar/**/test/**') => {},
+        Pathname.new('bar/**/spec/*')  => {},
+        Pathname.new('bar/**/.spec/*') => {}
       }.extend(described_class)
     end
 
@@ -62,6 +65,42 @@
       expect(hit.to_s).to eq('foo/bar')
     end
 
+    it 'returns the corresponding directory when source_base_dir matches the Dir.glob like pattern' do
+      source_base_dir = 'bar/something/test'
+      hit = directives.send :best_match_for, source_base_dir
+      expect(hit.to_s).to eq('bar/**/test/**')
+    end
+
+    it 'returns the corresponding directory when source_base_dir is a leaf of the Dir.glob like pattern' do
+      source_base_dir = 'bar/something/test/with/some/subdirectory'
+      hit = directives.send :best_match_for, source_base_dir
+      expect(hit.to_s).to eq('bar/**/test/**')
+    end
+
+    it 'returns the corresponding directory when source_base_dir is a direct leaf of the Dir.glob like pattern' do
+      source_base_dir = 'bar/something/spec/direct'
+      hit = directives.send :best_match_for, source_base_dir
+      expect(hit.to_s).to eq('bar/**/spec/*')
+    end
+
+    it 'returns the corresponding directory when source_base_dir contains a . character' do
+      source_base_dir = 'bar/something/.spec/direct'
+      hit = directives.send :best_match_for, source_base_dir
+      expect(hit.to_s).to eq('bar/**/.spec/*')
+    end
+
+    it 'does not match an arbitrary directory when source_base_dir contains a character that could match the .' do
+      source_base_dir = 'bar/something/aspec/direct'
+      hit = directives.send :best_match_for, source_base_dir
+      expect(hit.to_s).to eq('')
+    end
+
+    it 'returns nil when source_base_dir is a not direct leaf of the Dir.glob one-folder pattern' do
+      source_base_dir = 'bar/something/spec/with/some/subdirectory'
+      hit = directives.send :best_match_for, source_base_dir
+      expect(hit).to be_nil
+    end
+
     it 'returns nil we are on top of the tree and all other directories are below' do
       source_base_dir = 'foo'
       hit = directives.send :best_match_for, source_base_dir