From 3f51d2b779e30be00a871163101b261428a0421a Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Wed, 23 Apr 2025 11:22:55 +0900
Subject: [PATCH 1/2] Add Encoding::UNICODE_VERSION constant

---
 enc/unicode.c |  2 --
 encoding.c    | 11 +++++++++++
 inits.c       |  1 +
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/enc/unicode.c b/enc/unicode.c
index 18fba02476af66..cbfc6cdf589681 100644
--- a/enc/unicode.c
+++ b/enc/unicode.c
@@ -801,7 +801,6 @@ onigenc_unicode_case_map(OnigCaseFoldType* flagP,
   return (int )(to - to_start);
 }
 
-#if 0
 const char onigenc_unicode_version_string[] =
 #ifdef ONIG_UNICODE_VERSION_STRING
     ONIG_UNICODE_VERSION_STRING
@@ -817,4 +816,3 @@ const int onigenc_unicode_version_number[3] = {
     0
 #endif
 };
-#endif
diff --git a/encoding.c b/encoding.c
index e6b49ef14557b2..e2aaadb5b98603 100644
--- a/encoding.c
+++ b/encoding.c
@@ -1953,6 +1953,17 @@ Init_Encoding(void)
     rb_marshal_define_compat(rb_cEncoding, Qnil, 0, enc_m_loader);
 }
 
+void
+Init_unicode_version(void)
+{
+    extern const char onigenc_unicode_version_string[];
+
+    VALUE str = rb_usascii_str_new_static(onigenc_unicode_version_string,
+                                          strlen(onigenc_unicode_version_string));
+    OBJ_FREEZE(str);
+    rb_define_const(rb_cEncoding, "UNICODE_VERSION", str);
+}
+
 void
 Init_encodings(void)
 {
diff --git a/inits.c b/inits.c
index 94cec780ad60f5..79683185df3779 100644
--- a/inits.c
+++ b/inits.c
@@ -75,6 +75,7 @@ rb_call_inits(void)
     CALL(ast);
     CALL(shape);
     CALL(Prism);
+    CALL(unicode_version);
 
     // enable builtin loading
     CALL(builtin);

From d05a8fd766c3be4332dfd2660d990e615d58c393 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Wed, 23 Apr 2025 12:58:09 +0900
Subject: [PATCH 2/2] Check Unicode version of the normalization table

---
 lib/unicode_normalize/tables.rb | 3 +++
 template/unicode_norm_gen.tmpl  | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/lib/unicode_normalize/tables.rb b/lib/unicode_normalize/tables.rb
index 98b6ab01c9b377..b5b708defd4b01 100644
--- a/lib/unicode_normalize/tables.rb
+++ b/lib/unicode_normalize/tables.rb
@@ -1,6 +1,9 @@
 # coding: us-ascii
 # frozen_string_literal: true
 
+Encoding::UNICODE_VERSION == "16.0.0" or
+  raise "Unicode version mismatch: 16.0.0 expected but #{Encoding::UNICODE_VERSION}"
+
 # automatically generated by template/unicode_norm_gen.tmpl
 
 module UnicodeNormalize  # :nodoc:
diff --git a/template/unicode_norm_gen.tmpl b/template/unicode_norm_gen.tmpl
index c115e6eef925d3..17505f100e9f8e 100644
--- a/template/unicode_norm_gen.tmpl
+++ b/template/unicode_norm_gen.tmpl
@@ -166,6 +166,9 @@ end
 # frozen_string_literal: true
 %# >
 
+Encoding::UNICODE_VERSION == <%= unicode_version.dump %><%=%> or
+  raise "Unicode version mismatch: <%= unicode_version %> expected but #{Encoding::UNICODE_VERSION}"
+
 # automatically generated by template/unicode_norm_gen.tmpl
 
 module UnicodeNormalize  # :nodoc: