Bug #6487

* io.c (io_strip_bom): check EOF.  [Bug #6487][ruby-core:45203]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35766 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 51 insertions, 0 deletions

diff --git a/test/ruby/test_file.rb b/test/ruby/test_file.rb
index 54983d6deb..f94e4336d7 100644
--- a/test/ruby/test_file.rb
+++ b/test/ruby/test_file.rb
@@ -38,6 +38,57 @@ class TestFile < Test::Unit::TestCase
 
   include TestEOF::Seek
 
+  def test_empty_file_bom
+    bug6487 = '[ruby-core:45203]'
+    f = Tempfile.new(__method__.to_s)
+    f.close
+    assert File.exist? f.path
+    assert_nothing_raised(bug6487) {File.read(f.path, mode: 'r:utf-8')}
+    assert_nothing_raised(bug6487) {File.read(f.path, mode: 'r:bom|utf-8')}
+    f.close(true)
+  end
+
+  def assert_bom(bytes, name)
+    bug6487 = '[ruby-core:45203]'
+
+    f = Tempfile.new(name.to_s)
+    f.sync = true
+    expected = ""
+    result = nil
+    bytes[0...-1].each do |x|
+      f.write x
+      f.write ' '
+      f.pos -= 1
+      expected << x
+      assert_nothing_raised(bug6487) {result = File.read(f.path, mode: 'rb:bom|utf-8')}
+      assert_equal("#{expected} ".force_encoding("utf-8"), result)
+    end
+    f.write bytes[-1]
+    assert_nothing_raised(bug6487) {result = File.read(f.path, mode: 'rb:bom|utf-8')}
+    assert_equal '', result, "valid bom"
+    f.close(true)
+  end
+
+  def test_bom_8
+    assert_bom(["\xEF", "\xBB", "\xBF"], __method__)
+  end
+
+  def test_bom_16be
+    assert_bom(["\xFE", "\xFF"], __method__)
+  end
+
+  def test_bom_16le
+    assert_bom(["\xFF", "\xFE"], __method__)
+  end
+
+  def test_bom_32be
+    assert_bom(["\0", "\0", "\xFE", "\xFF"], __method__)
+  end
+
+  def test_bom_32le
+    assert_bom(["\xFF\xFE\0", "\0"], __method__)
+  end
+
   def test_truncate_wbuf
     f = Tempfile.new("test-truncate")
     f.print "abc"