merge revision(s) 8ce2fb9bbbaea14737c84385b1573f743a30f773,3a0f6ce1d31eefd8af01b50f3632a64d64e8f8c1: [Backport #19415]

	Only emit circular dependency warning for owned thread shields [Bug
	 #19415]

	If multiple threads attemps to load the same file concurrently
	it's not a circular dependency issue.

	So we check that the existing ThreadShield is owner by the current
	fiber before warning about circular dependencies.
	---
	 internal/thread.h                                     |  1 +
	 load.c                                                |  3 ++-
	 spec/ruby/core/kernel/shared/require.rb               | 11 +++++++++++
	 spec/ruby/fixtures/code/concurrent_require_fixture.rb |  4 ++++
	 test/ruby/test_require.rb                             |  3 ---
	 thread.c                                              | 11 +++++++++++
	 6 files changed, 29 insertions(+), 4 deletions(-)
	 create mode 100644 spec/ruby/fixtures/code/concurrent_require_fixture.rb

	Use Thread.pass until thread.stop? to wait for thread to block

	[Bug #19415]

	It should be more reliable
	---
	 spec/ruby/fixtures/code/concurrent_require_fixture.rb | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)

7 files changed, 30 insertions, 5 deletions

diff --git a/internal/thread.h b/internal/thread.h
index 6394f88d34..c3e54de683 100644
--- a/internal/thread.h
+++ b/internal/thread.h
@@ -29,6 +29,7 @@ VALUE rb_get_coverages(void);
 int rb_get_coverage_mode(void);
 VALUE rb_default_coverage(int);
 VALUE rb_thread_shield_new(void);
+bool rb_thread_shield_owned(VALUE self);
 VALUE rb_thread_shield_wait(VALUE self);
 VALUE rb_thread_shield_release(VALUE self);
 VALUE rb_thread_shield_destroy(VALUE self);
diff --git a/load.c b/load.c
index 282bebdb62..f3d39c2c08 100644
--- a/load.c
+++ b/load.c
@@ -850,7 +850,8 @@ load_lock(rb_vm_t *vm, const char *ftptr, bool warn)
         st_insert(loading_tbl, (st_data_t)ftptr, data);
         return (char *)ftptr;
     }
-    if (warn) {
+
+    if (warn && rb_thread_shield_owned((VALUE)data)) {
         VALUE warning = rb_warning_string("loading in progress, circular require considered harmful - %s", ftptr);
         rb_backtrace_each(rb_str_append, warning);
         rb_warning("%"PRIsVALUE, warning);
diff --git a/spec/ruby/core/kernel/shared/require.rb b/spec/ruby/core/kernel/shared/require.rb
index 666ca15e11..ae814aa317 100644
--- a/spec/ruby/core/kernel/shared/require.rb
+++ b/spec/ruby/core/kernel/shared/require.rb
@@ -237,6 +237,17 @@ describe :kernel_require, shared: true do
       }.should complain(/circular require considered harmful/, verbose: true)
       ScratchPad.recorded.should == [:loaded]
     end
+
+    ruby_bug "#17340", ''...'3.3' do
+      it "loads a file concurrently" do
+        path = File.expand_path "concurrent_require_fixture.rb", CODE_LOADING_DIR
+        ScratchPad.record(@object)
+        -> {
+          @object.require(path)
+        }.should_not complain(/circular require considered harmful/, verbose: true)
+        ScratchPad.recorded.join
+      end
+    end
   end
 
   describe "(non-extensioned path)" do
diff --git a/spec/ruby/fixtures/code/concurrent_require_fixture.rb b/spec/ruby/fixtures/code/concurrent_require_fixture.rb
new file mode 100644
index 0000000000..d4ce734183
--- /dev/null
+++ b/spec/ruby/fixtures/code/concurrent_require_fixture.rb
@@ -0,0 +1,4 @@
+object = ScratchPad.recorded
+thread = Thread.new { object.require(__FILE__) }
+Thread.pass until thread.stop?
+ScratchPad.record(thread)
diff --git a/test/ruby/test_require.rb b/test/ruby/test_require.rb
index 604ddf09d8..e0cfc8c914 100644
--- a/test/ruby/test_require.rb
+++ b/test/ruby/test_require.rb
@@ -562,9 +562,6 @@ class TestRequire < Test::Unit::TestCase
 
       assert_equal(true, (t1_res ^ t2_res), bug5754 + " t1:#{t1_res} t2:#{t2_res}")
       assert_equal([:pre, :post], scratch, bug5754)
-
-      assert_match(/circular require/, output)
-      assert_match(/in #{__method__}'$/o, output)
     }
   ensure
     $VERBOSE = verbose
diff --git a/thread.c b/thread.c
index 56a5644552..3f43e1272e 100644
--- a/thread.c
+++ b/thread.c
@@ -4922,6 +4922,17 @@ rb_thread_shield_new(void)
     return thread_shield;
 }
 
+bool
+rb_thread_shield_owned(VALUE self)
+{
+    VALUE mutex = GetThreadShieldPtr(self);
+    if (!mutex) return false;
+
+    rb_mutex_t *m = mutex_ptr(mutex);
+
+    return m->fiber == GET_EC()->fiber_ptr;
+}
+
 /*
  * Wait a thread shield.
  *
diff --git a/version.h b/version.h
index a9c6268d68..0cacda8c37 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 1
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 31
+#define RUBY_PATCHLEVEL 33
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"