ast.c: Fix to raise `SyntaxError`

* ast.c: Fix to raise `SyntaxError` when `RubyVM::AST.parse`
  or `RubyVM::AST.parse_file` fail to parse input.
* test/ruby/test_ast.rb: Add test cases for invalid syntax.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63602 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 31 insertions, 4 deletions

diff --git a/ast.c b/ast.c
index 1f0fde4bb1..d295ff9157 100644
--- a/ast.c
+++ b/ast.c
@@ -58,10 +58,13 @@ rb_ast_s_parse(VALUE module, VALUE str)
     const VALUE parser = rb_parser_new();
 
     str = rb_check_string_type(str);
-    rb_parser_set_context(parser, NULL, 1);
+    rb_parser_set_context(parser, NULL, 0);
     ast = rb_parser_compile_string_path(parser, rb_str_new_cstr("no file name"), str, 1);
 
-    if (!ast->body.root) return Qnil;
+    if (!ast->body.root) {
+        rb_ast_dispose(ast);
+        rb_exc_raise(GET_EC()->errinfo);
+    }
 
     obj = ast_new_internal(ast, (NODE *)ast->body.root);
 
@@ -80,12 +83,15 @@ rb_ast_s_parse_file(VALUE module, VALUE path)
     FilePathValue(path);
     f = rb_file_open_str(path, "r");
     rb_funcall(f, rb_intern("set_encoding"), 2, rb_enc_from_encoding(enc), rb_str_new_cstr("-"));
-    rb_parser_set_context(parser, NULL, 1);
+    rb_parser_set_context(parser, NULL, 0);
     ast = rb_parser_compile_file_path(parser, path, f, 1);
 
     rb_io_close(f);
 
-    if (!ast->body.root) return Qnil;
+    if (!ast->body.root) {
+        rb_ast_dispose(ast);
+        rb_exc_raise(GET_EC()->errinfo);
+    }
 
     obj = ast_new_internal(ast, (NODE *)ast->body.root);
 
diff --git a/test/ruby/test_ast.rb b/test/ruby/test_ast.rb
index 5a9bded19b..4696472965 100644
--- a/test/ruby/test_ast.rb
+++ b/test/ruby/test_ast.rb
@@ -150,4 +150,25 @@ class TestAst < Test::Unit::TestCase
     assert_equal(0, node.first_column)
     assert_equal(5, node.last_column)
   end
+
+  def test_parse_raises_syntax_error
+    assert_raise(SyntaxError) { RubyVM::AST.parse("end") }
+  end
+
+  def test_parse_file_raises_syntax_error
+    Tempfile.create(%w"test_ast .rb") do |f|
+      f.puts "end"
+      f.close
+      path = f.path
+      assert_in_out_err(%W[- #{path}], "#{<<-"begin;"}\n#{<<-"end;"}", /keyword_end/, [], success: true)
+      begin;
+        path = ARGV[0]
+        begin
+          RubyVM::AST.parse_file(path)
+        rescue SyntaxError => e
+          puts e.message
+        end
+      end;
+    end
+  end
 end