Fix an infinite loop for Style/RaiseArgs with `EnforcedStyle: compa…

…ct` when passing than 2 arguments to `raise`

The following test caused the loop: https://github.com/rubocop/rubocop/blob/5ee786dcadfa3c91096d9e81dcd16e4776ca6186/spec/rubocop/cop/style/raise_args_spec.rb#L130-L140

This changes `expect_no_corrections`  to always raise if there are correctors. In this case, the corrector replaced nothing, resulting in the same cop
being invocted again for the same reason.

The source assertion is left in because it produces nice diffs if there are actually changes.

changelog/fix_infinite_loop_for_style_raise_args.md

@@ -0,0 +1 @@
+* [#12774](https://github.com/rubocop/rubocop/pull/12774): Fix an infinite loop for `Style/RaiseArgs` with `EnforcedStyle: compact` when passing more than 2 arguments to `raise`. ([@earlopain][])

lib/rubocop/cop/style/raise_args.rb

@@ -80,7 +80,7 @@ def correction_compact_to_exploded(node)
 
         def correction_exploded_to_compact(node)
           exception_node, *message_nodes = *node.arguments
-          return node.source if message_nodes.size > 1
+          return if message_nodes.size > 1
 
           argument = message_nodes.first.source
           exception_class = exception_node.receiver&.source || exception_node.source

lib/rubocop/rspec/expect_offense.rb

@@ -169,12 +169,13 @@ def expect_no_corrections
 
         return if @last_corrector.empty?
 
-        # In order to print a nice diff, e.g. what source got corrected to,
-        # we need to run the actual corrections
-
+        # This is just here for a pretty diff if the source actually got changed
         new_source = @last_corrector.rewrite
-
         expect(new_source).to eq(@processed_source.buffer.source)
+
+        # There is an infinite loop if a corrector is present that did not make
+        # any changes. It will cause the same offense/correction on the next loop.
+        raise RuboCop::Runner::InfiniteCorrectionLoop.new(@processed_source.path, [@offenses])
       end
 
       def expect_no_offenses(source, file = nil)