1 files changed, 39 insertions, 0 deletions
diff --git a/lib/syntax_suggest/ripper_errors.rb b/lib/syntax_suggest/ripper_errors.rb
new file mode 100644
index 0000000000..4e2bc90948
--- /dev/null
+++ b/lib/syntax_suggest/ripper_errors.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module SyntaxSuggest
+  # Capture parse errors from Ripper
+  #
+  # Prism returns the errors with their messages, but Ripper
+  # does not. To get them we must make a custom subclass.
+  #
+  # Example:
+  #
+  #   puts RipperErrors.new(" def foo").call.errors
+  #   # => ["syntax error, unexpected end-of-input, expecting ';' or '\\n'"]
+  class RipperErrors < Ripper
+    attr_reader :errors
+
+    # Comes from ripper, called
+    # on every parse error, msg
+    # is a string
+    def on_parse_error(msg)
+      @errors ||= []
+      @errors << msg
+    end
+
+    alias_method :on_alias_error, :on_parse_error
+    alias_method :on_assign_error, :on_parse_error
+    alias_method :on_class_name_error, :on_parse_error
+    alias_method :on_param_error, :on_parse_error
+    alias_method :compile_error, :on_parse_error
+
+    def call
+      @run_once ||= begin
+        @errors = []
+        parse
+        true
+      end
+      self
+    end
+  end
+end