From 740ffa76c05b9627d8be481e2a7b5869c7b0c46a Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Sun, 29 Jun 2025 16:07:07 +0900
Subject: [PATCH 1/2] Fix OptionParser#program_name not to strip suffix
 unexpectedly

---
 lib/optparse.rb                | 10 +++++++++-
 test/optparse/test_optparse.rb | 12 ++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib/optparse.rb b/lib/optparse.rb
index 9cbd377..7838af7 100644
--- a/lib/optparse.rb
+++ b/lib/optparse.rb
@@ -1294,7 +1294,15 @@ def banner
   # to $0.
   #
   def program_name
-    @program_name || File.basename($0, '.*')
+    @program_name || strip_ext(File.basename($0))
+  end
+
+  private def strip_ext(name)  # :nodoc:
+    exts = /#{
+      require "rbconfig"
+      Regexp.union(RbConfig::CONFIG["EXECUTABLE_EXTS"])
+    }\z/o
+    name.sub(exts, "")
   end
 
   # for experimental cascading :-)
diff --git a/test/optparse/test_optparse.rb b/test/optparse/test_optparse.rb
index d50203b..ae12ae5 100644
--- a/test/optparse/test_optparse.rb
+++ b/test/optparse/test_optparse.rb
@@ -216,4 +216,16 @@ def stdout.tty?; true; end
       end
     end
   end
+
+  def test_program_name
+    program = $0
+    $0 = "rdbg3.5"
+    assert_equal "rdbg3.5", OptionParser.new.program_name
+    RbConfig::CONFIG["EXECUTABLE_EXTS"].split(" ") do |ext|
+      $0 = "rdbg3.5" + ext
+      assert_equal "rdbg3.5", OptionParser.new.program_name
+    end
+  ensure
+    $0 = program
+  end
 end

From 15b2f00b6bed354bf66a98a4759626ed41aedd4b Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Sun, 29 Jun 2025 16:50:09 +0900
Subject: [PATCH 2/2] JRuby does not have EXECUTABLE_EXTS in RbConfg::CONFIG

---
 lib/optparse.rb                | 2 +-
 test/optparse/test_optparse.rb | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/optparse.rb b/lib/optparse.rb
index 7838af7..332aea2 100644
--- a/lib/optparse.rb
+++ b/lib/optparse.rb
@@ -1300,7 +1300,7 @@ def program_name
   private def strip_ext(name)  # :nodoc:
     exts = /#{
       require "rbconfig"
-      Regexp.union(RbConfig::CONFIG["EXECUTABLE_EXTS"])
+      Regexp.union(*RbConfig::CONFIG["EXECUTABLE_EXTS"]&.split(" "))
     }\z/o
     name.sub(exts, "")
   end
diff --git a/test/optparse/test_optparse.rb b/test/optparse/test_optparse.rb
index ae12ae5..ff33400 100644
--- a/test/optparse/test_optparse.rb
+++ b/test/optparse/test_optparse.rb
@@ -221,7 +221,7 @@ def test_program_name
     program = $0
     $0 = "rdbg3.5"
     assert_equal "rdbg3.5", OptionParser.new.program_name
-    RbConfig::CONFIG["EXECUTABLE_EXTS"].split(" ") do |ext|
+    RbConfig::CONFIG["EXECUTABLE_EXTS"]&.split(" ") do |ext|
       $0 = "rdbg3.5" + ext
       assert_equal "rdbg3.5", OptionParser.new.program_name
     end