Respect ERB tag boundaries when detecting magic comments

lib/erb/compiler.rb

@@ -452,7 +452,7 @@ def initialize(trim_mode)
   attr_accessor :content
 
   def detect_magic_comment(s, enc = nil)
-    re = @percent ? /\G(?:<%#(.*)%>|%#(.*)\n)/ : /\G<%#(.*)%>/
+    re = @percent ? /\G(?:<%#(.*?)%>|%#(.*)\n)/ : /\G<%#(.*?)%>/
     frozen = nil
     s.scan(re) do
       comment = $+

test/erb/test_erb.rb

@@ -595,6 +595,13 @@ def test_frozen_string_literal
     end
   end
 
+  def test_frozen_string_literal_after_encoding_comment
+    [nil, '%'].each do |trim_mode|
+      erb = @erb.new("<%# coding: utf-8 %><%# frozen_string_literal: true %><%= ''.frozen? %>", trim_mode: trim_mode)
+      assert_equal("true", erb.result)
+    end
+  end
+
   def test_result_with_hash
     erb = @erb.new("<%= foo %>")
     assert_equal("1", erb.result_with_hash(foo: "1"))

test/erb/test_erb_m17n.rb

@@ -92,6 +92,13 @@ def test_recognize_magic_comment
     assert_equal Encoding::EUC_KR, erb.result.encoding
   end
 
+  def test_ignore_magic_comment_after_code
+    [nil, '%'].each do |trim_mode|
+      erb = ERB.new("<%# hello %><%= 1 %><%# coding: euc-jp %>", trim_mode: trim_mode)
+      assert_equal Encoding::UTF_8, erb.encoding
+    end
+  end
+
   module M; end
   def test_method_with_encoding
     obj = Object.new