From 041c59e7ebf99dc4bcff4b8f94142a04d99e4ed2 Mon Sep 17 00:00:00 2001
From: Igor Novokshonov <gogainda@yandex.ru>
Date: Thu, 8 Apr 2021 21:31:31 +0200
Subject: [PATCH 1/2] Fix rpartition result when regexp doesn't match

---
 spec/ruby/core/string/rpartition_spec.rb |  8 ++++++++
 src/main/ruby/truffleruby/core/string.rb | 10 +++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/spec/ruby/core/string/rpartition_spec.rb b/spec/ruby/core/string/rpartition_spec.rb
index c6428636f6a1..6979114d5632 100644
--- a/spec/ruby/core/string/rpartition_spec.rb
+++ b/spec/ruby/core/string/rpartition_spec.rb
@@ -11,6 +11,14 @@
     "hello".rpartition("hello").should == ["", "hello", ""]
   end
 
+  it "returns original string if regexp doesn't match" do
+    "hello".rpartition("/x/").should == ["", "", "hello"]
+  end
+
+  it "returns new object if doesn't match" do
+    "hello".rpartition("/no_match/").last.object_id.should_not eql("hello".object_id)
+  end
+
   it "accepts regexp" do
     "hello!".rpartition(/l./).should == ["hel", "lo", "!"]
   end
diff --git a/src/main/ruby/truffleruby/core/string.rb b/src/main/ruby/truffleruby/core/string.rb
index 883d4c2ed2a9..bdf489d527cf 100644
--- a/src/main/ruby/truffleruby/core/string.rb
+++ b/src/main/ruby/truffleruby/core/string.rb
@@ -205,7 +205,7 @@ def rpartition(pattern)
     if pattern.kind_of? Regexp
       if m = Truffle::RegexpOperations.search_region(pattern, self, 0, size, false)
         Primitive.regexp_last_match_set(Primitive.caller_special_variables, m)
-        [m.pre_match, m[0], m.post_match]
+        return [m.pre_match, m[0], m.post_match]
       end
     else
       pattern = StringValue(pattern)
@@ -217,11 +217,11 @@ def rpartition(pattern)
                 pattern.dup,
                 Primitive.string_substring(self, post_start, post_len)]
       end
-
-      # Nothing worked out, this is the default.
-      empty = String.new(encoding: encoding)
-      [empty, empty.dup, self]
     end
+
+    # Nothing worked out, this is the default.
+    empty = String.new(encoding: encoding)
+    [empty, empty.dup, self.dup]
   end
 
   def rstrip

From abfe81768787e5d8c40ec83d3b6f223369fb31e3 Mon Sep 17 00:00:00 2001
From: Igor Novokshonov <gogainda@yandex.ru>
Date: Fri, 9 Apr 2021 17:39:48 +0200
Subject: [PATCH 2/2] Fix multibyte handling

---
 CHANGELOG.md                             | 1 +
 spec/ruby/core/string/rpartition_spec.rb | 4 ++++
 src/main/ruby/truffleruby/core/string.rb | 2 +-
 test/mri/excludes/TestString.rb          | 1 -
 4 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f459df230003..6d9f7c19b3d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ Bug fixes:
 Compatibility:
 
 * Make interpolated strings frozen for compatibility with Ruby 2.7 (#2304, @kirs).
+* Make rpartition compatible with Ruby 2.7 (#2320, @gogainda).
 
 Performance:
 
diff --git a/spec/ruby/core/string/rpartition_spec.rb b/spec/ruby/core/string/rpartition_spec.rb
index 6979114d5632..b2f5e54ee776 100644
--- a/spec/ruby/core/string/rpartition_spec.rb
+++ b/spec/ruby/core/string/rpartition_spec.rb
@@ -19,6 +19,10 @@
     "hello".rpartition("/no_match/").last.object_id.should_not eql("hello".object_id)
   end
 
+  it "handles multibyte string correctly" do
+    "ユーザ@ドメイン".rpartition(/@/).should == ["ユーザ", "@", "ドメイン"]
+  end
+
   it "accepts regexp" do
     "hello!".rpartition(/l./).should == ["hel", "lo", "!"]
   end
diff --git a/src/main/ruby/truffleruby/core/string.rb b/src/main/ruby/truffleruby/core/string.rb
index bdf489d527cf..c8622599d600 100644
--- a/src/main/ruby/truffleruby/core/string.rb
+++ b/src/main/ruby/truffleruby/core/string.rb
@@ -203,7 +203,7 @@ def partition(pattern=nil)
 
   def rpartition(pattern)
     if pattern.kind_of? Regexp
-      if m = Truffle::RegexpOperations.search_region(pattern, self, 0, size, false)
+      if m = Truffle::RegexpOperations.search_region(pattern, self, 0, bytesize, false)
         Primitive.regexp_last_match_set(Primitive.caller_special_variables, m)
         return [m.pre_match, m[0], m.post_match]
       end
diff --git a/test/mri/excludes/TestString.rb b/test/mri/excludes/TestString.rb
index 2ca455e5d399..5c754197c3e8 100644
--- a/test/mri/excludes/TestString.rb
+++ b/test/mri/excludes/TestString.rb
@@ -14,7 +14,6 @@
 exclude :test_lines, "needs investigation"
 exclude :test_partition, "needs investigation"
 exclude :test_respond_to, "needs investigation"
-exclude :test_rpartition, "needs investigation"
 exclude :test_rstrip, "needs investigation"
 exclude :test_rstrip_bang, "needs investigation"
 exclude :test_setter, "needs investigation"