From 958dbf41f3b8f00c18e2e01ae1c6c818e0738c1b Mon Sep 17 00:00:00 2001
From: Roman Sandler <5535625+sandlerr@users.noreply.github.com>
Date: Mon, 26 Dec 2022 23:19:01 +1100
Subject: [PATCH 1/9] Initial Ractor support

---
 ext/sqlite3/extconf.rb          |  3 ++
 ext/sqlite3/sqlite3.c           |  6 +++
 lib/sqlite3.rb                  |  5 ++
 sqlite3.gemspec                 |  1 +
 test/helper.rb                  |  1 +
 test/test_integration_ractor.rb | 87 +++++++++++++++++++++++++++++++++
 6 files changed, 103 insertions(+)
 create mode 100644 test/test_integration_ractor.rb

diff --git a/ext/sqlite3/extconf.rb b/ext/sqlite3/extconf.rb
index 733e22d5..9152f471 100644
--- a/ext/sqlite3/extconf.rb
+++ b/ext/sqlite3/extconf.rb
@@ -115,6 +115,9 @@ def configure_extension
         # Functions defined in 2.1 but not 2.0
         have_func("rb_integer_pack")
 
+        # Functions defined in 3.0 but not 2.7
+        have_func("rb_ext_ractor_safe")
+
         # These functions may not be defined
         have_func("sqlite3_initialize")
         have_func("sqlite3_backup_init")
diff --git a/ext/sqlite3/sqlite3.c b/ext/sqlite3/sqlite3.c
index c0672a06..b7bdd729 100644
--- a/ext/sqlite3/sqlite3.c
+++ b/ext/sqlite3/sqlite3.c
@@ -91,6 +91,12 @@ init_sqlite3_constants(void)
     VALUE mSqlite3Constants;
     VALUE mSqlite3Open;
 
+#ifdef HAVE_RB_EXT_RACTOR_SAFE
+    if (sqlite3_threadsafe()) {
+        rb_ext_ractor_safe(true);
+    }
+#endif
+
     mSqlite3Constants = rb_define_module_under(mSqlite3, "Constants");
 
     /* sqlite3_open_v2 flags for Database::new */
diff --git a/lib/sqlite3.rb b/lib/sqlite3.rb
index 790fd754..9fab21e7 100644
--- a/lib/sqlite3.rb
+++ b/lib/sqlite3.rb
@@ -14,4 +14,9 @@ module SQLite3
   def self.threadsafe?
     threadsafe > 0
   end
+
+  # Is the gem's C extension marked as Ractor-safe?
+  def self.ractor_safe?
+    threadsafe? && !defined?(Ractor).nil?
+  end
 end
diff --git a/sqlite3.gemspec b/sqlite3.gemspec
index d0746454..183dcc2a 100644
--- a/sqlite3.gemspec
+++ b/sqlite3.gemspec
@@ -83,6 +83,7 @@ Gem::Specification.new do |s|
     "test/test_integration_aggregate.rb",
     "test/test_integration_open_close.rb",
     "test/test_integration_pending.rb",
+    "test/test_integration_ractor.rb",
     "test/test_integration_resultset.rb",
     "test/test_integration_statement.rb",
     "test/test_pragmas.rb",
diff --git a/test/helper.rb b/test/helper.rb
index 5ea6da11..930858b6 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -9,6 +9,7 @@
 puts "info: sqlite version: #{SQLite3::SQLITE_VERSION}/#{SQLite3::SQLITE_LOADED_VERSION}"
 puts "info: sqlcipher?: #{SQLite3.sqlcipher?}"
 puts "info: threadsafe?: #{SQLite3.threadsafe?}"
+puts "info: ractor_safe?: #{SQLite3.ractor_safe?}"
 
 module SQLite3
   class TestCase < Minitest::Test
diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
new file mode 100644
index 00000000..e058029d
--- /dev/null
+++ b/test/test_integration_ractor.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+require "helper"
+require "fileutils"
+
+class IntegrationRactorTestCase < SQLite3::TestCase
+  STRESS_DB_NAME = "stress.db"
+
+  def setup
+    teardown
+  end
+
+  def teardown
+    FileUtils.rm_rf(Dir.glob("#{STRESS_DB_NAME}*"))
+  end
+
+  def test_ractor_safe
+    skip unless RUBY_VERSION >= "3.0" && SQLite3.threadsafe?
+    assert_predicate SQLite3, :ractor_safe?
+  end
+
+  def test_ractor_share_database
+    skip("Requires Ruby with Ractors") unless SQLite3.ractor_safe?
+
+    db_receiver = Ractor.new do
+      db = Ractor.receive
+      Ractor.yield db.object_id
+      begin
+        db.execute("create table test_table ( b integer primary key)")
+        raise "Should have raised an exception in db.execute()"
+      rescue => e
+        Ractor.yield e
+      end
+    end
+    db_creator = Ractor.new(db_receiver) do |db_receiver|
+      db = SQLite3::Database.open(":memory:")
+      Ractor.yield db.object_id
+      db_receiver.send(db)
+      sleep 0.1
+      db.execute("create table test_table ( a integer primary key)")
+    end
+    first_oid = db_creator.take
+    second_oid = db_receiver.take
+    assert_not_equal first_oid, second_oid
+    ex = db_receiver.take
+    # For now, let's assert that you can't pass database connections around
+    # between different Ractors. Letting a live DB connection exist in two
+    # threads that are running concurrently might expose us to footguns and
+    # lead to data corruption, so we should avoid this possibility and wait
+    # until connections can be given away using `yield` or `send`.
+    assert_equal "prepare called on a closed database", ex.message
+  end
+
+  def test_ractor_stress
+    skip("Requires Ruby with Ractors") unless SQLite3.ractor_safe?
+
+    # Testing with a file instead of :memory: since it can be more realistic
+    # compared with real production use, and so discover problems that in-
+    # memory testing won't find. Trivial example: STRESS_DB_NAME needs to be
+    # frozen to pass into the Ractor, but :memory: might avoid that problem by
+    # using a literal string.
+    db = SQLite3::Database.open(STRESS_DB_NAME)
+    db.execute("PRAGMA journal_mode=WAL") # A little slow without this
+    db.execute("create table stress_test (a integer primary_key, b text)")
+    random = Random.new.freeze
+    ractors = (0..9).map do |ractor_number|
+      Ractor.new(random, ractor_number) do |random, ractor_number|
+        db_in_ractor = SQLite3::Database.open(STRESS_DB_NAME)
+        db_in_ractor.busy_handler do
+          sleep random.rand / 100 # Lots of busy errors happen with multiple concurrent writers
+          true
+        end
+        100.times do |i|
+          db_in_ractor.execute("insert into stress_test(a, b) values (#{ractor_number * 100 + i}, '#{random.rand}')")
+        end
+      end
+    end
+    ractors.each { |r| r.take }
+    final_check = Ractor.new do
+      db_in_ractor = SQLite3::Database.open(STRESS_DB_NAME)
+      res = db_in_ractor.execute("select count(*) from stress_test")
+      Ractor.yield res
+    end
+    res = final_check.take
+    assert_equal 1000, res[0][0]
+  end
+end

From 6ccb27b405f50787e7a1a0c487549fec589c2d05 Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike.dalessio@gmail.com>
Date: Wed, 10 Jan 2024 16:21:39 -0500
Subject: [PATCH 2/9] test: handle Ruby 3.3 behavior around passing unshareable
 objects

---
 test/test_integration_ractor.rb | 43 ++++++++++++++-------------------
 1 file changed, 18 insertions(+), 25 deletions(-)

diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
index e058029d..f4f4d5d0 100644
--- a/test/test_integration_ractor.rb
+++ b/test/test_integration_ractor.rb
@@ -22,33 +22,26 @@ def test_ractor_safe
   def test_ractor_share_database
     skip("Requires Ruby with Ractors") unless SQLite3.ractor_safe?
 
-    db_receiver = Ractor.new do
-      db = Ractor.receive
-      Ractor.yield db.object_id
-      begin
-        db.execute("create table test_table ( b integer primary key)")
-        raise "Should have raised an exception in db.execute()"
-      rescue => e
-        Ractor.yield e
+    db = SQLite3::Database.open(":memory:")
+
+    if RUBY_VERSION >= "3.3"
+      # after ruby/ruby@ce47ee00
+      ractor = Ractor.new do
+        Ractor.receive
       end
+
+      assert_raises(Ractor::Error) { ractor.send(db) }
+    else
+      # before ruby/ruby@ce47ee00 T_DATA objects could be copied
+      ractor = Ractor.new do
+        local_db = Ractor.receive
+        Ractor.yield local_db.object_id
+      end
+      ractor.send(db)
+      copy_id = ractor.take
+
+      assert_not_equal db.object_id, copy_id
     end
-    db_creator = Ractor.new(db_receiver) do |db_receiver|
-      db = SQLite3::Database.open(":memory:")
-      Ractor.yield db.object_id
-      db_receiver.send(db)
-      sleep 0.1
-      db.execute("create table test_table ( a integer primary key)")
-    end
-    first_oid = db_creator.take
-    second_oid = db_receiver.take
-    assert_not_equal first_oid, second_oid
-    ex = db_receiver.take
-    # For now, let's assert that you can't pass database connections around
-    # between different Ractors. Letting a live DB connection exist in two
-    # threads that are running concurrently might expose us to footguns and
-    # lead to data corruption, so we should avoid this possibility and wait
-    # until connections can be given away using `yield` or `send`.
-    assert_equal "prepare called on a closed database", ex.message
   end
 
   def test_ractor_stress

From 2b0fff51eccb34dd75d07e495b33042468590e47 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Wed, 26 Mar 2025 15:11:30 -0700
Subject: [PATCH 3/9] Allow databases to be shareable but only in full-mutex
 mode

  https://www.sqlite.org/threadsafe.html

"Full mutex" mode is the only time when a SQLite database can be shared
between multiple threads.  Multi-thread mode only means that multiple
threads can have their own instances of a database object that point at
the same file, but multiple threads cannot access the object
concurrently.
---
 ext/sqlite3/database.c          |  4 +++
 lib/sqlite3/database.rb         |  2 +-
 test/test_integration_ractor.rb | 43 +++++++++------------------------
 3 files changed, 16 insertions(+), 33 deletions(-)

diff --git a/ext/sqlite3/database.c b/ext/sqlite3/database.c
index a35ff3a1..885aa3c7 100644
--- a/ext/sqlite3/database.c
+++ b/ext/sqlite3/database.c
@@ -158,6 +158,10 @@ rb_sqlite3_open_v2(VALUE self, VALUE file, VALUE mode, VALUE zvfs)
         ctx->flags |= SQLITE3_RB_DATABASE_READONLY;
     }
 
+    if (flags & SQLITE_OPEN_FULLMUTEX) {
+        FL_SET_RAW(self, RUBY_FL_SHAREABLE);
+    }
+
     return self;
 }
 
diff --git a/lib/sqlite3/database.rb b/lib/sqlite3/database.rb
index efa91a95..e12e81c1 100644
--- a/lib/sqlite3/database.rb
+++ b/lib/sqlite3/database.rb
@@ -181,7 +181,7 @@ def initialize file, options = {}, zvfs = nil
 
       initialize_extensions(options[:extensions])
 
-      ForkSafety.track(self)
+      ForkSafety.track(self) if Ractor.main?
 
       if block_given?
         begin
diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
index f4f4d5d0..cebd112b 100644
--- a/test/test_integration_ractor.rb
+++ b/test/test_integration_ractor.rb
@@ -44,37 +44,16 @@ def test_ractor_share_database
     end
   end
 
-  def test_ractor_stress
-    skip("Requires Ruby with Ractors") unless SQLite3.ractor_safe?
-
-    # Testing with a file instead of :memory: since it can be more realistic
-    # compared with real production use, and so discover problems that in-
-    # memory testing won't find. Trivial example: STRESS_DB_NAME needs to be
-    # frozen to pass into the Ractor, but :memory: might avoid that problem by
-    # using a literal string.
-    db = SQLite3::Database.open(STRESS_DB_NAME)
-    db.execute("PRAGMA journal_mode=WAL") # A little slow without this
-    db.execute("create table stress_test (a integer primary_key, b text)")
-    random = Random.new.freeze
-    ractors = (0..9).map do |ractor_number|
-      Ractor.new(random, ractor_number) do |random, ractor_number|
-        db_in_ractor = SQLite3::Database.open(STRESS_DB_NAME)
-        db_in_ractor.busy_handler do
-          sleep random.rand / 100 # Lots of busy errors happen with multiple concurrent writers
-          true
-        end
-        100.times do |i|
-          db_in_ractor.execute("insert into stress_test(a, b) values (#{ractor_number * 100 + i}, '#{random.rand}')")
-        end
-      end
-    end
-    ractors.each { |r| r.take }
-    final_check = Ractor.new do
-      db_in_ractor = SQLite3::Database.open(STRESS_DB_NAME)
-      res = db_in_ractor.execute("select count(*) from stress_test")
-      Ractor.yield res
-    end
-    res = final_check.take
-    assert_equal 1000, res[0][0]
+  def test_shareable_db
+    # databases are shareable between ractors, but only if they're opened
+    # in "full mutex" mode
+    db = SQLite3::Database.new ":memory:",
+      flags: SQLite3::Constants::Open::FULLMUTEX |
+      SQLite3::Constants::Open::READWRITE |
+      SQLite3::Constants::Open::CREATE
+    assert Ractor.shareable?(db)
+
+    db = SQLite3::Database.new ":memory:"
+    refute Ractor.shareable?(db)
   end
 end

From 46fcc4206972855abea4b16050749ee4d4ead5a4 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Wed, 26 Mar 2025 16:09:28 -0700
Subject: [PATCH 4/9] Fix cop?

---
 test/test_integration_ractor.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
index cebd112b..fdc5f23a 100644
--- a/test/test_integration_ractor.rb
+++ b/test/test_integration_ractor.rb
@@ -49,8 +49,8 @@ def test_shareable_db
     # in "full mutex" mode
     db = SQLite3::Database.new ":memory:",
       flags: SQLite3::Constants::Open::FULLMUTEX |
-      SQLite3::Constants::Open::READWRITE |
-      SQLite3::Constants::Open::CREATE
+        SQLite3::Constants::Open::READWRITE |
+        SQLite3::Constants::Open::CREATE
     assert Ractor.shareable?(db)
 
     db = SQLite3::Database.new ":memory:"

From 9e64a7ad43ad2cd0118ff05919c33c27fa10778f Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Wed, 26 Mar 2025 16:16:14 -0700
Subject: [PATCH 5/9] remove dead code

---
 test/test_integration_ractor.rb | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
index fdc5f23a..66d707de 100644
--- a/test/test_integration_ractor.rb
+++ b/test/test_integration_ractor.rb
@@ -4,16 +4,6 @@
 require "fileutils"
 
 class IntegrationRactorTestCase < SQLite3::TestCase
-  STRESS_DB_NAME = "stress.db"
-
-  def setup
-    teardown
-  end
-
-  def teardown
-    FileUtils.rm_rf(Dir.glob("#{STRESS_DB_NAME}*"))
-  end
-
   def test_ractor_safe
     skip unless RUBY_VERSION >= "3.0" && SQLite3.threadsafe?
     assert_predicate SQLite3, :ractor_safe?

From c7a24ba7372775cb183d6519bb1c9e94060e6ef4 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Wed, 26 Mar 2025 16:49:06 -0700
Subject: [PATCH 6/9] not all versions of Ruby have Ractor.main?

---
 lib/sqlite3/database.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/sqlite3/database.rb b/lib/sqlite3/database.rb
index c9dc491b..a04338b5 100644
--- a/lib/sqlite3/database.rb
+++ b/lib/sqlite3/database.rb
@@ -183,7 +183,7 @@ def initialize file, options = {}, zvfs = nil
 
       initialize_extensions(options[:extensions])
 
-      ForkSafety.track(self) if Ractor.main?
+      ForkSafety.track(self) if Ractor.main == Ractor.current
 
       if block_given?
         begin

From 90dec0aeeaf44f7b62009a8286ad38e93eb889f6 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Wed, 26 Mar 2025 16:53:22 -0700
Subject: [PATCH 7/9] Check for Ractor constant

TruffleRuby support
---
 lib/sqlite3/database.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/sqlite3/database.rb b/lib/sqlite3/database.rb
index a04338b5..4d3279e8 100644
--- a/lib/sqlite3/database.rb
+++ b/lib/sqlite3/database.rb
@@ -183,7 +183,7 @@ def initialize file, options = {}, zvfs = nil
 
       initialize_extensions(options[:extensions])
 
-      ForkSafety.track(self) if Ractor.main == Ractor.current
+      ForkSafety.track(self) if !defined?(Ractor) || (Ractor.main == Ractor.current)
 
       if block_given?
         begin

From 0d2ee9682c89da22fb9c02831b3d7a94d0df5cab Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Wed, 26 Mar 2025 17:20:45 -0700
Subject: [PATCH 8/9] more TruffleRuby

---
 test/test_integration_ractor.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
index 66d707de..49dee789 100644
--- a/test/test_integration_ractor.rb
+++ b/test/test_integration_ractor.rb
@@ -35,6 +35,8 @@ def test_ractor_share_database
   end
 
   def test_shareable_db
+    skip unless defined?(Ractor)
+
     # databases are shareable between ractors, but only if they're opened
     # in "full mutex" mode
     db = SQLite3::Database.new ":memory:",

From 433c2d3174b9b9c57255e3f8975c71bdcc567890 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <tenderlove@ruby-lang.org>
Date: Thu, 27 Mar 2025 09:36:24 -0700
Subject: [PATCH 9/9] more truffle ruby

---
 test/test_integration_ractor.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/test_integration_ractor.rb b/test/test_integration_ractor.rb
index 49dee789..009d386e 100644
--- a/test/test_integration_ractor.rb
+++ b/test/test_integration_ractor.rb
@@ -6,6 +6,7 @@
 class IntegrationRactorTestCase < SQLite3::TestCase
   def test_ractor_safe
     skip unless RUBY_VERSION >= "3.0" && SQLite3.threadsafe?
+    skip unless defined?(Ractor)
     assert_predicate SQLite3, :ractor_safe?
   end