Make Style/GuardClause a bit more lenient when the replacement would make the code more verbose

changelog/change_make_styleguardclause_a_bit_more_lenient.md

@@ -0,0 +1 @@
+* [#10740](https://github.com/rubocop/rubocop/pull/10740): Make `Style/GuardClause` a bit more lenient when the replacement would make the code more verbose. ([@dvandersluis][])

config/default.yml

@@ -3703,7 +3703,7 @@ Style/GuardClause:
   StyleGuide: '#no-nested-conditionals'
   Enabled: true
   VersionAdded: '0.20'
-  VersionChanged: '1.28'
+  VersionChanged: '<<next>>'
   # `MinBodyLength` defines the number of lines of the a body of an `if` or `unless`
   # needs to have to trigger this cop
   MinBodyLength: 1

lib/rubocop/cop/style/guard_clause.rb

@@ -110,7 +110,7 @@ def on_if(node)
           kw = if guard_clause_in_if
                  node.loc.keyword.source
                else
-                 opposite_keyword(node)
+                 node.inverse_keyword
                end
 
           register_offense(node, guard_clause_source(guard_clause), kw)
@@ -123,7 +123,7 @@ def check_ending_if(node)
           return if allowed_consecutive_conditionals? &&
                     consecutive_conditionals?(node.parent, node)
 
-          register_offense(node, 'return', opposite_keyword(node))
+          register_offense(node, 'return', node.inverse_keyword)
         end
 
         def consecutive_conditionals?(parent, node)
@@ -134,14 +134,12 @@ def consecutive_conditionals?(parent, node)
           end
         end
 
-        def opposite_keyword(node)
-          node.if? ? 'unless' : 'if'
-        end
-
         def register_offense(node, scope_exiting_keyword, conditional_keyword)
           condition, = node.node_parts
           example = [scope_exiting_keyword, conditional_keyword, condition.source].join(' ')
           if too_long_for_single_line?(node, example)
+            return if trivial?(node)
+
             example = "#{conditional_keyword} #{condition.source}; #{scope_exiting_keyword}; end"
           end
 
@@ -167,6 +165,10 @@ def accepted_form?(node, ending: false)
           accepted_if?(node, ending) || node.condition.multiline? || node.parent&.assignment?
         end
 
+        def trivial?(node)
+          node.branches.one? && !node.if_branch.if_type? && !node.if_branch.begin_type?
+        end
+
         def accepted_if?(node, ending)
           return true if node.modifier_form? || node.ternary?
 

spec/rubocop/cop/style/guard_clause_spec.rb

@@ -407,15 +407,47 @@ def func
   end
 
   context 'with Metrics/MaxLineLength enabled' do
-    it 'registers an offense with non-modifier example code if too long for single line' do
-      expect_offense(<<~RUBY)
-        def test
-          if something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line
-          ^^ Use a guard clause (`unless something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line; return; end`) instead of wrapping the code inside a conditional expression.
-            work
-          end
+    context 'when the correction is too long for a single line' do
+      context 'with a trivial body' do
+        it 'does not register an offense' do
+          expect_no_offenses(<<~RUBY)
+            def test
+              if something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line
+                work
+              end
+            end
+          RUBY
         end
-      RUBY
+      end
+
+      context 'with a nested `if` node' do
+        it 'does registers an offense' do
+          expect_offense(<<~RUBY)
+            def test
+              if something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line
+              ^^ Use a guard clause (`unless something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line; return; end`) instead of wrapping the code inside a conditional expression.
+                if something_else
+                  work
+                end
+              end
+            end
+          RUBY
+        end
+      end
+
+      context 'with a nested `begin` node' do
+        it 'does registers an offense' do
+          expect_offense(<<~RUBY)
+            def test
+              if something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line
+              ^^ Use a guard clause (`unless something && something_that_makes_the_guard_clause_too_long_to_fit_on_one_line; return; end`) instead of wrapping the code inside a conditional expression.
+                work
+                more_work
+              end
+            end
+          RUBY
+        end
+      end
     end
   end