[Fix #8132] Fix handling of names like _ and i with Naming/MethodName…

… and EnforcedStyle: camelCase (#8140)

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ### Bug fixes
 
+* [#8132](https://github.com/rubocop-hq/rubocop/issues/8132): Fix the problem with `Naming/MethodName: EnforcedStyle: camelCase` and `_` or `i` variables. ([@avrusanov][])
 * [#8115](https://github.com/rubocop-hq/rubocop/issues/8115): Fix false negative for `Lint::FormatParameterMismatch` when argument contains formatting. ([@andrykonchin][])
 * [#8131](https://github.com/rubocop-hq/rubocop/pull/8131): Fix false positive for `Style/RedundantRegexpEscape` with escaped delimiters. ([@owst][])
 * [#8124](https://github.com/rubocop-hq/rubocop/issues/8124): Fix a false positive for `Lint/FormatParameterMismatch` when using named parameters with escaped `%`. ([@koic][])
@@ -4586,3 +4587,4 @@
 [@ric2b]: https://github.com/ric2b
 [@burnettk]: https://github.com/burnettk
 [@andrykonchin]: https://github.com/andrykonchin
+[@avrusanov]: https://github.com/avrusanov

lib/rubocop/cop/mixin/configurable_naming.rb

@@ -9,7 +9,7 @@ module ConfigurableNaming
 
       FORMATS = {
         snake_case: /^@{0,2}[\da-z_]+[!?=]?$/,
-        camelCase:  /^@{0,2}_?[a-z][\da-zA-Z]+[!?=]?$/
+        camelCase:  /^@{0,2}(?:_|_?[a-z][\da-zA-Z]*)[!?=]?$/
       }.freeze
     end
   end

spec/rubocop/cop/naming/variable_name_spec.rb

@@ -17,6 +17,14 @@
     it 'accepts assignment with indexing of self' do
       expect_no_offenses('self[:a] = b')
     end
+
+    it 'accepts local variables marked as unused' do
+      expect_no_offenses('_ = 1')
+    end
+
+    it 'accepts one symbol size local variables' do
+      expect_no_offenses('i = 1')
+    end
   end
 
   context 'when configured for snake_case' do