[pull] master from ruby:master

io.c

@@ -4900,7 +4900,7 @@ static VALUE
 rb_io_each_codepoint(VALUE io)
 {
     rb_io_t *fptr;
-    rb_encoding *enc;
+    rb_encoding *enc, *read_enc;
     unsigned int c;
     int r, n;
 
@@ -4914,12 +4914,13 @@ rb_io_each_codepoint(VALUE io)
         r = 1;		/* no invalid char yet */
         for (;;) {
             make_readconv(fptr, 0);
+            read_enc = io_read_encoding(fptr);
             for (;;) {
                 if (fptr->cbuf.len) {
-                    if (fptr->encs.enc)
+                    if (read_enc)
                         r = rb_enc_precise_mbclen(fptr->cbuf.ptr+fptr->cbuf.off,
                                                   fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
-                                                  fptr->encs.enc);
+                                                  read_enc);
                     else
                         r = ONIGENC_CONSTRUCT_MBCLEN_CHARFOUND(1);
                     if (!MBCLEN_NEEDMORE_P(r))
@@ -4931,21 +4932,21 @@ rb_io_each_codepoint(VALUE io)
                 if (more_char(fptr) == MORE_CHAR_FINISHED) {
                     clear_readconv(fptr);
                     if (!MBCLEN_CHARFOUND_P(r)) {
-                        enc = fptr->encs.enc;
+                        enc = read_enc;
                         goto invalid;
                     }
                     return io;
                 }
             }
             if (MBCLEN_INVALID_P(r)) {
-                enc = fptr->encs.enc;
+                enc = read_enc;
                 goto invalid;
             }
             n = MBCLEN_CHARFOUND_LEN(r);
-            if (fptr->encs.enc) {
+            if (read_enc) {
                 c = rb_enc_codepoint(fptr->cbuf.ptr+fptr->cbuf.off,
                                      fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
-                                     fptr->encs.enc);
+                                     read_enc);
             }
             else {
                 c = (unsigned char)fptr->cbuf.ptr[fptr->cbuf.off];

test/ruby/test_io_m17n.rb

@@ -2806,4 +2806,17 @@ def test_each_codepoint_need_more
       flunk failure.join("\n---\n")
     end
   end
+
+  def test_each_codepoint_encoding_with_ungetc
+    File.open(File::NULL, "rt:utf-8") do |f|
+      f.ungetc(%Q[\u{3042}\u{3044}\u{3046}])
+      assert_equal [0x3042, 0x3044, 0x3046], f.each_codepoint.to_a
+    end
+    File.open(File::NULL, "rt:us-ascii") do |f|
+      f.ungetc(%Q[\u{3042}\u{3044}\u{3046}])
+      assert_raise(ArgumentError) do
+        f.each_codepoint.to_a
+      end
+    end
+  end
 end

test/rubygems/test_gem_package_tar_header_ractor.rb

@@ -58,4 +58,4 @@ def test_encode_in_ractor
       assert_headers_equal header_bytes, new_header_bytes
     RUBY
   end
-end
+end unless RUBY_PLATFORM.match?(/mingw|mswin/)

tool/lib/core_assertions.rb

@@ -391,7 +391,6 @@ def assert_separately(args, file = nil, line = nil, src, ignore_stderr: nil, **o
       # Run Ractor-related test without influencing the main test suite
       def assert_ractor(src, args: [], require: nil, require_relative: nil, file: nil, line: nil, ignore_stderr: nil, **opt)
         omit unless defined?(Ractor)
-        omit if windows?
 
         # https://bugs.ruby-lang.org/issues/21262
         shim_value = "class Ractor; alias value take; end" unless Ractor.method_defined?(:value)

tool/sync_default_gems.rb

@@ -61,7 +61,10 @@ def lib((upstream, branch), gemspec_in_subdir: false)
     ])
   end
 
-  # Note: tool/auto_review_pr.rb also depends on this constant.
+  # Note: tool/auto_review_pr.rb also depends on these constants.
+  NO_UPSTREAM = [
+    "lib/unicode_normalize",    # not to match with "lib/un"
+  ]
   REPOSITORIES = {
     "io-console": repo("ruby/io-console", [
       ["ext/io/console", "ext/io/console"],
@@ -295,6 +298,7 @@ def lib((upstream, branch), gemspec_in_subdir: false)
 
   class << Repository
     def find_upstream(file)
+      return if NO_UPSTREAM.any? {|dst| file.start_with?(dst) }
       REPOSITORIES.find do |repo_name, repository|
         if repository.mappings.any? {|_src, dst| file.start_with?(dst) }
           break repo_name

tool/test/test_sync_default_gems.rb

@@ -346,5 +346,20 @@ def test_squash_merge
       assert_equal("[ruby/#@target] Merge commit", subject, out)
       assert_includes(body, "Commit in branch", out)
     end
+
+    def test_no_upstream_file
+      group = SyncDefaultGems::Repository.group(%w[
+          lib/un.rb
+          lib/unicode_normalize/normalize.rb
+          lib/unicode_normalize/tables.rb
+          lib/net/https.rb
+      ])
+      expected = {
+        "un" => %w[lib/un.rb],
+        "net-http" => %w[lib/net/https.rb],
+        nil => %w[lib/unicode_normalize/normalize.rb lib/unicode_normalize/tables.rb],
+      }
+      assert_equal(expected, group)
+    end
   end if /darwin|linux/ =~ RUBY_PLATFORM
 end