Also handle string conversion in Ripper.lex

In `ripper`, both go through the same converion logic.
Needed for rspec, no other failures in their own tests

Author: Earlopain

lib/prism/translation/ripper.rb

@@ -69,7 +69,7 @@ def self.parse(src, filename = "(ripper)", lineno = 1)
       #          [[1, 13], :on_kw,     "end", END      ]]
       #
       def self.lex(src, filename = "-", lineno = 1, raise_errors: false)
-        result = Prism.lex_compat(src, filepath: filename, line: lineno, version: "current")
+        result = Prism.lex_compat(coerce_source(src), filepath: filename, line: lineno, version: "current")
 
         if result.failure? && raise_errors
           raise SyntaxError, result.errors.first.message
@@ -91,6 +91,21 @@ def self.tokenize(...)
         lex(...).map { |token| token[2] }
       end
 
+      # Mirros the various lex_types that ripper supports
+      def self.coerce_source(source) # :nodoc:
+        if source.is_a?(IO)
+          source.read
+        elsif source.respond_to?(:gets)
+          src = +""
+          while line = source.gets
+            src << line
+          end
+          src
+        else
+          source.to_str
+        end
+      end
+
       # This contains a table of all of the parser events and their
       # corresponding arity.
       PARSER_EVENT_TABLE = {
@@ -480,17 +495,7 @@ def self.lex_state_name(state)
 
       # Create a new Translation::Ripper object with the given source.
       def initialize(source, filename = "(ripper)", lineno = 1)
-        if source.is_a?(IO)
-          @source = source.read
-        elsif source.respond_to?(:gets)
-          @source = +""
-          while line = source.gets
-            @source << line
-          end
-        else
-          @source = source.to_str
-        end
-
+        @source = Ripper.coerce_source(source)
         @filename = filename
         @lineno = lineno
         @column = 0

test/prism/ruby/ripper_test.rb

@@ -243,6 +243,14 @@ def string_like.to_str
       end
     end
 
+    def test_lex_coersion
+      string_like = Object.new
+      def string_like.to_str
+        "a"
+      end
+      assert_equal Ripper.lex(string_like), Translation::Ripper.lex(string_like)
+    end
+
     # Check that the hardcoded values don't change without us noticing.
     def test_internals
       actual = Translation::Ripper.constants.select { |name| name.start_with?("EXPR_") }.sort