[Fix rubocop#7885] Consider Layout/IndentationStyle:EnforcedStyle

When calculating how wide the indentation is, we must look at the
`EnforcedStyle` of the `Layout/IndentationStyle` cop. If it's `spaces`, then
the indentation multiplier is 1. If it's `tabs` it's a bit more complicated,
but that part was already handled correctly.

The specs needed to be updated with correct configuration for all cases with
`tabs` indentation.

Whether or not we should consider the `Enabled` parameter is debatable. I've
chosen to not care about `Enabled`, and to use the other parameter settings in
any case.

CHANGELOG.md

@@ -19,6 +19,7 @@
 * [#7905](https://github.com/rubocop-hq/rubocop/pull/7905): Fix an error when running `rubocop --only` or `rubocop --except` options without cop name argument. ([@koic][])
 * [#7903](https://github.com/rubocop-hq/rubocop/pull/7903): Fix an incorrect autocorrect for `Style/HashTransformKeys` and `Style/HashTransformValues` cops when line break before `to_h` method. ([@diogoosorio][], [@koic][])
 * [#7899](https://github.com/rubocop-hq/rubocop/issues/7899): Fix an infinite loop error for `Layout/SpaceAroundOperators` with `Layout/ExtraSpacing` when using `ForceEqualSignAlignment: true`. ([@koic][])
+* [#7885](https://github.com/rubocop-hq/rubocop/issues/7885): Fix `Style/IfUnlessModifier` logic when tabs are used for indentation. ([@jonas054][])
 
 ### Changes
 

lib/rubocop/cop/mixin/statement_modifier.rb

@@ -58,10 +58,11 @@ def max_line_length
       end
 
       def indentation_multiplier
-        return 1 if config.for_cop('Layout/IndentationStyle')['Enabled']
+        indentation_style_config = config.for_cop('Layout/IndentationStyle')
+        return 1 if indentation_style_config['EnforcedStyle'] == 'spaces'
 
         default_configuration = RuboCop::ConfigLoader.default_configuration
-        config.for_cop('Layout/IndentationStyle')['IndentationWidth'] ||
+        indentation_style_config['IndentationWidth'] ||
           config.for_cop('Layout/IndentationWidth')['Width'] ||
           default_configuration
             .for_cop('Layout/IndentationStyle')['IndentationWidth'] ||

spec/rubocop/cop/style/if_unless_modifier_spec.rb

@@ -6,7 +6,11 @@
   subject(:cop) { described_class.new(config) }
 
   let(:config) do
-    RuboCop::Config.new('Layout/LineLength' => line_length_config)
+    RuboCop::Config.new('Layout/LineLength' => line_length_config,
+                        'Layout/IndentationStyle' => {
+                          'Enabled' => true,
+                          'EnforcedStyle' => 'spaces'
+                        })
   end
   let(:line_length_config) do
     {
@@ -517,7 +521,7 @@ def f
     end
   end
 
-  context 'with disabled Layout/IndentationStyle cop' do
+  context 'with tabs used for indentation' do
     shared_examples 'with tabs indentation' do
       let(:source) do
         # Empty lines should make no difference.
@@ -567,7 +571,8 @@ def f
             'Width' => 1
           },
           'Layout/IndentationStyle' => {
-            'Enabled' => false,
+            'Enabled' => true,
+            'EnforcedStyle' => 'tabs',
             'IndentationWidth' => 2
           },
           'Layout/LineLength' => { 'Max' => 10 + 12 } # 12 is indentation
@@ -584,7 +589,8 @@ def f
             'Width' => 1
           },
           'Layout/IndentationStyle' => {
-            'Enabled' => false
+            'Enabled' => false,
+            'EnforcedStyle' => 'tabs'
           },
           'Layout/LineLength' => { 'Max' => 10 + 6 } # 6 is indentation
         )
@@ -597,7 +603,8 @@ def f
       let(:config) do
         RuboCop::Config.new(
           'Layout/IndentationStyle' => {
-            'Enabled' => false
+            'Enabled' => false,
+            'EnforcedStyle' => 'tabs'
           },
           'Layout/LineLength' => { 'Max' => 10 + 12 } # 12 is indentation
         )