Explicitly freeze concatenated-String constants to unbreak on non-main Ractors.

lib/addressable/uri.rb

@@ -37,20 +37,26 @@ class InvalidURIError < StandardError
     ##
     # Container for the character classes specified in
     # <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986</a>.
+    #
+    # Note: Concatenated and interpolated `String`s are not affected by the
+    #       `frozen_string_literal` directive and must be frozen explicitly.
+    #
+    #       Interpolated `String`s *were* frozen this way before Ruby 3.0:
+    #       https://bugs.ruby-lang.org/issues/17104
     module CharacterClasses
       ALPHA = "a-zA-Z"
       DIGIT = "0-9"
       GEN_DELIMS = "\\:\\/\\?\\#\\[\\]\\@"
       SUB_DELIMS = "\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\="
-      RESERVED = GEN_DELIMS + SUB_DELIMS
-      UNRESERVED = ALPHA + DIGIT + "\\-\\.\\_\\~"
-      PCHAR = UNRESERVED + SUB_DELIMS + "\\:\\@"
-      SCHEME = ALPHA + DIGIT + "\\-\\+\\."
-      HOST = UNRESERVED + SUB_DELIMS + "\\[\\:\\]"
-      AUTHORITY = PCHAR + "\\[\\]"
-      PATH = PCHAR + "\\/"
-      QUERY = PCHAR + "\\/\\?"
-      FRAGMENT = PCHAR + "\\/\\?"
+      RESERVED = (GEN_DELIMS + SUB_DELIMS).freeze
+      UNRESERVED = (ALPHA + DIGIT + "\\-\\.\\_\\~").freeze
+      PCHAR = (UNRESERVED + SUB_DELIMS + "\\:\\@").freeze
+      SCHEME = (ALPHA + DIGIT + "\\-\\+\\.").freeze
+      HOST = (UNRESERVED + SUB_DELIMS + "\\[\\:\\]").freeze
+      AUTHORITY = (PCHAR + "\\[\\:\\]").freeze
+      PATH = (PCHAR + "\\/").freeze
+      QUERY = (PCHAR + "\\/\\?").freeze
+      FRAGMENT = (PCHAR + "\\/\\?").freeze
     end
 
     module NormalizeCharacterClasses

spec/addressable/uri_spec.rb

@@ -6667,3 +6667,13 @@ def to_str
     expect(@uri.class).to eq(@uri.join('path').class)
   end
 end
+
+describe Addressable::URI, "when initialized in a non-main `Ractor`" do
+  it "should have the same value as if used in the main `Ractor`" do
+    pending("Ruby 3.0+ for `Ractor` support") unless defined?(Ractor)
+    main = Addressable::URI.parse("http://example.com")
+    expect(
+      Ractor.new { Addressable::URI.parse("http://example.com") }.take
+    ).to eq(main)
+  end
+end