merge revision(s) 391abc543cea118a9cd7d6310acadbfa352668ef,e86c1f6fc53433ef5c82ed2b7a4cc9a12c153e4c,f6539202c52a051a4e6946a318a1d9cd29002990: [Backport #12052]

	Scan the coderange in the given encoding

	---
	 ext/-test-/string/enc_str_buf_cat.c       | 14 ++++++++++++++
	 string.c                                  | 32 ++++++++++++++++++++++---------
	 test/-ext-/string/test_enc_str_buf_cat.rb |  9 +++++++++
	 3 files changed, 46 insertions(+), 9 deletions(-)

	Work around issue transcoding issue with non-ASCII compatible
	 encodings and xml escaping

	When using a non-ASCII compatible source and destination encoding
	and xml escaping (the :xml option to String#encode), the resulting
	string was broken, as it used the correct non-ASCII compatible
	encoding, but contained data that was ASCII-compatible instead of
	compatible with the string's encoding.

	Work around this issue by detecting the case where both the
	source and destination encoding are non-ASCII compatible, and
	transcoding the source string from the non-ASCII compatible
	encoding to UTF-8. The xml escaping code will correctly handle
	the UTF-8 source string and the return the correctly encoded
	and escaped value.

	Fixes [Bug #12052]

	Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
	---
	 test/ruby/test_transcode.rb | 19 +++++++++++++++++++
	 transcode.c                 |  6 ++++++
	 2 files changed, 25 insertions(+)

	=?UTF-8?q?-=20add=20regression=20tests=20for=20U+6E7F=20(?=
	 =?UTF-8?q?=E6=B9=BF)=20in=20ISO-2022-JP?=
	MIME-Version: 1.0
	Content-Type: text/plain; charset=UTF-8
	Content-Transfer-Encoding: 8bit

	  In ISO-2022-JP, the bytes use to code are the same as those for "<>".
	  This adds regression tests to make sure that these bytes, when representing
	  湿, are NOT　escaped with encode("ISO-2022-JP, xml: :text) or similar.
	  These are additional regression tests for #12052.
	---
	 test/ruby/test_transcode.rb | 3 +++
	 1 file changed, 3 insertions(+)

6 files changed, 75 insertions, 10 deletions

diff --git a/ext/-test-/string/enc_str_buf_cat.c b/ext/-test-/string/enc_str_buf_cat.c
index 9ac4a298be..4c1b262e1e 100644
--- a/ext/-test-/string/enc_str_buf_cat.c
+++ b/ext/-test-/string/enc_str_buf_cat.c
@@ -7,8 +7,22 @@ enc_str_buf_cat(VALUE str, VALUE str2)
     return rb_enc_str_buf_cat(str, RSTRING_PTR(str2), RSTRING_LEN(str2), rb_enc_get(str2));
 }
 
+static VALUE
+str_conv_enc_opts(VALUE str, VALUE from, VALUE to, VALUE ecflags, VALUE ecopts)
+{
+    rb_encoding *from_enc = NIL_P(from) ? NULL : rb_to_encoding(from);
+    rb_encoding *to_enc = NIL_P(to) ? NULL : rb_to_encoding(to);
+    int flags = NUM2INT(ecflags);
+    if (!NIL_P(ecopts)) {
+        Check_Type(ecopts, T_HASH);
+        OBJ_FREEZE(ecopts);
+    }
+    return rb_str_conv_enc_opts(str, from_enc, to_enc, flags, ecopts);
+}
+
 void
 Init_string_enc_str_buf_cat(VALUE klass)
 {
     rb_define_method(klass, "enc_str_buf_cat", enc_str_buf_cat, 1);
+    rb_define_method(klass, "str_conv_enc_opts", str_conv_enc_opts, 4);
 }
diff --git a/string.c b/string.c
index c2919abeee..ed101187ab 100644
--- a/string.c
+++ b/string.c
@@ -698,6 +698,18 @@ rb_enc_cr_str_exact_copy(VALUE dest, VALUE src)
     ENC_CODERANGE_SET(dest, ENC_CODERANGE(src));
 }
 
+static int
+enc_coderange_scan(VALUE str, rb_encoding *enc, int encidx)
+{
+    if (rb_enc_mbminlen(enc) > 1 && rb_enc_dummy_p(enc) &&
+	rb_enc_mbminlen(enc = get_actual_encoding(encidx, str)) == 1) {
+	return ENC_CODERANGE_BROKEN;
+    }
+    else {
+	return coderange_scan(RSTRING_PTR(str), RSTRING_LEN(str), enc);
+    }
+}
+
 int
 rb_enc_str_coderange(VALUE str)
 {
@@ -706,14 +718,7 @@ rb_enc_str_coderange(VALUE str)
     if (cr == ENC_CODERANGE_UNKNOWN) {
 	int encidx = ENCODING_GET(str);
 	rb_encoding *enc = rb_enc_from_index(encidx);
-	if (rb_enc_mbminlen(enc) > 1 && rb_enc_dummy_p(enc) &&
-            rb_enc_mbminlen(enc = get_actual_encoding(encidx, str)) == 1) {
-	    cr = ENC_CODERANGE_BROKEN;
-	}
-	else {
-	    cr = coderange_scan(RSTRING_PTR(str), RSTRING_LEN(str),
-                                enc);
-	}
+	cr = enc_coderange_scan(str, enc, encidx);
         ENC_CODERANGE_SET(str, cr);
     }
     return cr;
@@ -955,6 +960,15 @@ static VALUE str_cat_conv_enc_opts(VALUE newstr, long ofs, const char *ptr, long
 				   rb_encoding *from, rb_encoding *to,
 				   int ecflags, VALUE ecopts);
 
+static inline bool
+is_enc_ascii_string(VALUE str, rb_encoding *enc)
+{
+    int encidx = rb_enc_to_index(enc);
+    if (rb_enc_get_index(str) == encidx)
+	return is_ascii_string(str);
+    return enc_coderange_scan(str, enc, encidx) == ENC_CODERANGE_7BIT;
+}
+
 VALUE
 rb_str_conv_enc_opts(VALUE str, rb_encoding *from, rb_encoding *to, int ecflags, VALUE ecopts)
 {
@@ -965,7 +979,7 @@ rb_str_conv_enc_opts(VALUE str, rb_encoding *from, rb_encoding *to, int ecflags,
     if (!to) return str;
     if (!from) from = rb_enc_get(str);
     if (from == to) return str;
-    if ((rb_enc_asciicompat(to) && is_ascii_string(str)) ||
+    if ((rb_enc_asciicompat(to) && is_enc_ascii_string(str, from)) ||
 	to == rb_ascii8bit_encoding()) {
 	if (STR_ENC_GET(str) != to) {
 	    str = rb_str_dup(str);
diff --git a/test/-ext-/string/test_enc_str_buf_cat.rb b/test/-ext-/string/test_enc_str_buf_cat.rb
index 72f903903c..b9a63ec2de 100644
--- a/test/-ext-/string/test_enc_str_buf_cat.rb
+++ b/test/-ext-/string/test_enc_str_buf_cat.rb
@@ -13,4 +13,13 @@ class Test_StringEncStrBufCat < Test::Unit::TestCase
     assert_equal(:unknown, Bug::String.new(cr_unknown_str).coderange, "an assertion for following tests")
     assert_equal(:valid, Bug::String.new(a8_str).enc_str_buf_cat(cr_unknown_str).coderange, Bug6509)
   end
+
+  def test_str_conv_enc
+    str = Bug::String.new("aaa".encode("US-ASCII"))
+    assert_same(str, str.str_conv_enc_opts("UTF-8", "US-ASCII", 0, nil))
+
+    str = Bug::String.new("aaa".encode("UTF-16LE").force_encoding("UTF-8"))
+    assert_predicate(str, :ascii_only?) # cache coderange
+    assert_equal("aaa", str.str_conv_enc_opts("UTF-16LE", "UTF-8", 0, nil))
+  end
 end
diff --git a/test/ruby/test_transcode.rb b/test/ruby/test_transcode.rb
index 04c8248697..c8b0034e06 100644
--- a/test/ruby/test_transcode.rb
+++ b/test/ruby/test_transcode.rb
@@ -126,6 +126,28 @@ class TestTranscode < Test::Unit::TestCase
     assert_equal("D\xFCrst".force_encoding('iso-8859-2'), "D\xFCrst".encode('iso-8859-2', 'iso-8859-1'))
   end
 
+  def test_encode_xml_multibyte
+    encodings = %w'UTF-8 UTF-16LE UTF-16BE UTF-32LE UTF-32BE'
+    encodings.each do |src_enc|
+      encodings.each do |dst_enc|
+        escaped = "<>".encode(src_enc).encode(dst_enc, :xml=>:text)
+        assert_equal("&lt;&gt;", escaped.encode('UTF-8'), "failed encoding #{src_enc} to #{dst_enc} with xml: :text")
+
+        escaped = '<">'.encode(src_enc).encode(dst_enc, :xml=>:attr)
+        assert_equal('"&lt;&quot;&gt;"', escaped.encode('UTF-8'), "failed encoding #{src_enc} to #{dst_enc} with xml: :attr")
+
+        escaped = "<>".encode(src_enc).force_encoding("UTF-8").encode(dst_enc, src_enc, :xml=>:text)
+        assert_equal("&lt;&gt;", escaped.encode('UTF-8'), "failed encoding #{src_enc} to #{dst_enc} with xml: :text")
+
+        escaped = '<">'.encode(src_enc).force_encoding("UTF-8").encode(dst_enc, src_enc, :xml=>:attr)
+        assert_equal('"&lt;&quot;&gt;"', escaped.encode('UTF-8'), "failed encoding #{src_enc} to #{dst_enc} with xml: :attr")
+      end
+    end
+    # regression test; U+6E7F (湿) uses the same bytes in ISO-2022-JP as "<>"
+    assert_equal(  "&lt;&gt;\u6E7F",   "<>\u6E7F".encode("ISO-2022-JP").encode("ISO-2022-JP", :xml=>:text).encode("UTF-8"))
+    assert_equal("\"&lt;&gt;\u6E7F\"", "<>\u6E7F".encode("ISO-2022-JP").encode("ISO-2022-JP", :xml=>:attr).encode("UTF-8"))
+  end
+
   def test_ascii_range
     encodings = [
       'US-ASCII', 'ASCII-8BIT',
diff --git a/transcode.c b/transcode.c
index a72afdc44b..d2abd9e0e5 100644
--- a/transcode.c
+++ b/transcode.c
@@ -2719,6 +2719,12 @@ str_transcode0(int argc, VALUE *argv, VALUE *self, int ecflags, VALUE ecopts)
         }
     }
     else {
+        if (senc && denc && !rb_enc_asciicompat(senc) && !rb_enc_asciicompat(denc)) {
+            rb_encoding *utf8 = rb_utf8_encoding();
+            str = rb_str_conv_enc(str, senc, utf8);
+            senc = utf8;
+            sname = "UTF-8";
+        }
         if (encoding_equal(sname, dname)) {
             sname = "";
             dname = "";
diff --git a/version.h b/version.h
index 0ae26b7a2a..b503513d1d 100644
--- a/version.h
+++ b/version.h
@@ -12,7 +12,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 3
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 109
+#define RUBY_PATCHLEVEL 110
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 7