[ruby/irb] Suppress crashing when EncodingError has occurred without lineno

https://github.com/ruby/irb/commit/13572d8cdc

lib/irb.rb

@@ -554,7 +554,8 @@ module IRB
 
     def handle_exception(exc)
       if exc.backtrace && exc.backtrace[0] =~ /\/irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
-         !(SyntaxError === exc)
+         !(SyntaxError === exc) && !(EncodingError === exc)
+        # The backtrace of invalid encoding hash (ex. {"\xAE": 1}) raises EncodingError without lineno.
         irb_bug = true
       else
         irb_bug = false

lib/irb/ruby-lex.rb

@@ -211,6 +211,8 @@ class RubyLex
       else
         RubyVM::InstructionSequence.compile(code)
       end
+    rescue EncodingError
+      # This is for a hash with invalid encoding symbol, {"\xAE": 1}
     rescue SyntaxError => e
       case e.message
       when /unterminated (?:string|regexp) meets end of file/

test/irb/test_context.rb

@@ -63,6 +63,13 @@ module TestIRB
       assert_not_match(/rescue _\.class/, e.message)
     end
 
+    def test_evaluate_with_encoding_error_without_lineno
+      assert_raise_with_message(EncodingError, /invalid symbol/) {
+        @context.evaluate(%q[{"\xAE": 1}], 1)
+        # The backtrace of this invalid encoding hash doesn't contain lineno.
+      }
+    end
+
     def test_evaluate_with_onigmo_warning
       assert_warning("(irb):1: warning: character class has duplicated range: /[aa]/\n") do
         @context.evaluate('/[aa]/', 1)