[pull] master from ruby:master

array.c

@@ -8423,12 +8423,12 @@ rb_ary_deconstruct(VALUE ary)
  *
  *      [1, 'one', :one, [2, 'two', :two]]
  *
- *  - A {%w or %W string-array Literal}[rdoc-ref:syntax/literals.rdoc@25w+and+-25W-3A+String-Array+Literals]:
+ *  - A {%w or %W string-array Literal}[rdoc-ref:syntax/literals.rdoc@w-and-w-String-Array-Literals]:
  *
  *      %w[foo bar baz] # => ["foo", "bar", "baz"]
  *      %w[1 % *]       # => ["1", "%", "*"]
  *
- *  - A {%i or %I symbol-array Literal}[rdoc-ref:syntax/literals.rdoc@25i+and+-25I-3A+Symbol-Array+Literals]:
+ *  - A {%i or %I symbol-array Literal}[rdoc-ref:syntax/literals.rdoc@i+and-I-Symbol-Array+Literals]:
  *
  *      %i[foo bar baz] # => [:foo, :bar, :baz]
  *      %i[1 % *]       # => [:"1", :%, :*]
@@ -8690,8 +8690,8 @@ rb_ary_deconstruct(VALUE ary)
  *
  *  First, what's elsewhere. Class \Array:
  *
- *  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- *  - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ *  - Inherits from {class Object}[rdoc-ref:Object@Whats-Here].
+ *  - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats-Here],
  *    which provides dozens of additional methods.
  *
  *  Here, class \Array provides methods that are useful for:

complex.c

@@ -2645,9 +2645,9 @@ float_arg(VALUE self)
  * First, what's elsewhere:
  *
  * - Class \Complex inherits (directly or indirectly)
- *   from classes {Numeric}[rdoc-ref:Numeric@What-27s+Here]
- *   and {Object}[rdoc-ref:Object@What-27s+Here].
- * - Includes (indirectly) module {Comparable}[rdoc-ref:Comparable@What-27s+Here].
+ *   from classes {Numeric}[rdoc-ref:Numeric@Whats-Here]
+ *   and {Object}[rdoc-ref:Object@Whats-Here].
+ * - Includes (indirectly) module {Comparable}[rdoc-ref:Comparable@Whats-Here].
  *
  * Here, class \Complex has methods for:
  *

dir.rb

@@ -31,7 +31,7 @@
 # A \Dir object is in some ways array-like:
 #
 # - It has instance methods #children, #each, and #each_child.
-# - It includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here].
+# - It includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here].
 #
 # == \Dir As Stream-Like
 #
@@ -85,8 +85,8 @@
 #
 # First, what's elsewhere. Class \Dir:
 #
-# - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
-# - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+# - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+# - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
 #   which provides dozens of additional methods.
 #
 # Here, class \Dir provides methods that are useful for:

doc/float.rb

@@ -72,9 +72,9 @@
 # First, what's elsewhere. Class \Float:
 #
 # - Inherits from
-#   {class Numeric}[rdoc-ref:Numeric@What-27s+Here]
-#   and {class Object}[rdoc-ref:Object@What-27s+Here].
-# - Includes {module Comparable}[rdoc-ref:Comparable@What-27s+Here].
+#   {class Numeric}[rdoc-ref:Numeric@Whats+Here]
+#   and {class Object}[rdoc-ref:Object@Whats+Here].
+# - Includes {module Comparable}[rdoc-ref:Comparable@Whats+Here].
 #
 # Here, class \Float provides methods for:
 #

doc/string.rb

@@ -163,8 +163,8 @@
 #
 # First, what's elsewhere. Class +String+:
 #
-# - Inherits from the {Object class}[rdoc-ref:Object@What-27s+Here].
-# - Includes the {Comparable module}[rdoc-ref:Comparable@What-27s+Here].
+# - Inherits from the {Object class}[rdoc-ref:Object@Whats+Here].
+# - Includes the {Comparable module}[rdoc-ref:Comparable@Whats+Here].
 #
 # Here, class +String+ provides methods that are useful for:
 #

eval.c

@@ -329,17 +329,24 @@ ruby_exec_node(void *n)
 
 /*
  *  call-seq:
- *     Module.nesting    -> array
- *
- *  Returns the list of +Modules+ nested at the point of call.
+ *     Module.nesting -> array
+ *
+ *  Returns nested module as an array of Module objects:
+ *
+ *    module M0
+ *      def self.speak = Module.nesting
+ *      module M1
+ *        def self.speak = Module.nesting
+ *        module M2
+ *          def self.speak = Module.nesting
+ *        end
+ *      end
+ *    end
+ *    M0.speak             # => [M0]
+ *    M0.speak.first.class # => Module
+ *    M0::M1.speak         # => [M0::M1, M0]
+ *    M0::M1::M2.speak     # => [M0::M1::M2, M0::M1, M0]
  *
- *     module M1
- *       module M2
- *         $a = Module.nesting
- *       end
- *     end
- *     $a           #=> [M1::M2, M1]
- *     $a[0].name   #=> "M1::M2"
  */
 
 static VALUE

file.c

@@ -7507,7 +7507,7 @@ const char ruby_null_device[] =
  *
  *  First, what's elsewhere. Class \File:
  *
- *  - Inherits from {class IO}[rdoc-ref:IO@What-27s+Here],
+ *  - Inherits from {class IO}[rdoc-ref:IO@Whats+Here],
  *    in particular, methods for creating, reading, and writing files
  *  - Includes module FileTest,
  *    which provides dozens of additional methods.

hash.c

@@ -7216,8 +7216,8 @@ static const rb_data_type_t env_data_type = {
  *
  *  First, what's elsewhere. Class +Hash+:
  *
- *  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- *  - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ *  - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ *  - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
  *    which provides dozens of additional methods.
  *
  *  Here, class +Hash+ provides methods that are useful for:
@@ -7528,8 +7528,8 @@ Init_Hash(void)
      *
      * First, what's elsewhere. Class +ENV+:
      *
-     * - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
-     * - Extends {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+     * - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+     * - Extends {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
      *
      * Here, class +ENV+ provides methods that are useful for:
      *

io.c

@@ -15469,8 +15469,8 @@ set_LAST_READ_LINE(VALUE val, ID _x, VALUE *_y)
  *
  *  First, what's elsewhere. Class \IO:
  *
- *  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- *  - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ *  - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ *  - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
  *    which provides dozens of additional methods.
  *
  *  Here, class \IO provides methods that are useful for:

lib/net/http.rb

@@ -460,7 +460,7 @@ class HTTPHeaderSyntaxError < StandardError; end
   #
   # First, what's elsewhere. Class Net::HTTP:
   #
-  # - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
+  # - Inherits from {class Object}[rdoc-ref:Object#class-object-whats-here].
   #
   # This is a categorized summary of methods and attributes.
   #
@@ -1304,7 +1304,7 @@ def response_body_encoding=(value)
 
     # Sets whether to determine the proxy from environment variable
     # '<tt>ENV['http_proxy']</tt>';
-    # see {Proxy Using ENV['http_proxy']}[rdoc-ref:Net::HTTP@Proxy+Using+-27ENV-5B-27http_proxy-27-5D-27].
+    # see {Proxy Using ENV['http_proxy']}[rdoc-ref:Net::HTTP@Proxy+Using+ENVHTTPProxy].
     attr_writer :proxy_from_env
 
     # Sets the proxy address;

lib/resolv.rb

@@ -487,13 +487,18 @@ def each_name(address)
     # * Resolv::DNS::Resource::IN::A
     # * Resolv::DNS::Resource::IN::AAAA
     # * Resolv::DNS::Resource::IN::ANY
+    # * Resolv::DNS::Resource::IN::CAA
     # * Resolv::DNS::Resource::IN::CNAME
     # * Resolv::DNS::Resource::IN::HINFO
+    # * Resolv::DNS::Resource::IN::HTTPS
+    # * Resolv::DNS::Resource::IN::LOC
     # * Resolv::DNS::Resource::IN::MINFO
     # * Resolv::DNS::Resource::IN::MX
     # * Resolv::DNS::Resource::IN::NS
     # * Resolv::DNS::Resource::IN::PTR
     # * Resolv::DNS::Resource::IN::SOA
+    # * Resolv::DNS::Resource::IN::SRV
+    # * Resolv::DNS::Resource::IN::SVCB
     # * Resolv::DNS::Resource::IN::TXT
     # * Resolv::DNS::Resource::IN::WKS
     #

numeric.c

@@ -3680,9 +3680,9 @@ rb_int128_to_numeric(rb_int128_t n)
  * First, what's elsewhere. Class \Integer:
  *
  * - Inherits from
- *   {class Numeric}[rdoc-ref:Numeric@What-27s+Here]
- *   and {class Object}[rdoc-ref:Object@What-27s+Here].
- * - Includes {module Comparable}[rdoc-ref:Comparable@What-27s+Here].
+ *   {class Numeric}[rdoc-ref:Numeric@Whats+Here]
+ *   and {class Object}[rdoc-ref:Object@Whats+Here].
+ * - Includes {module Comparable}[rdoc-ref:Comparable@Whats+Here].
  *
  * Here, class \Integer provides methods for:
  *
@@ -6365,8 +6365,8 @@ int_s_try_convert(VALUE self, VALUE num)
  *
  * First, what's elsewhere. Class \Numeric:
  *
- * - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- * - Includes {module Comparable}[rdoc-ref:Comparable@What-27s+Here].
+ * - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ * - Includes {module Comparable}[rdoc-ref:Comparable@Whats+Here].
  *
  * Here, class \Numeric provides methods for:
  *

object.c

@@ -4357,8 +4357,8 @@ rb_f_loop_size(VALUE self, VALUE args, VALUE eobj)
  *
  *  First, what's elsewhere. Class \Object:
  *
- *  - Inherits from {class BasicObject}[rdoc-ref:BasicObject@What-27s+Here].
- *  - Includes {module Kernel}[rdoc-ref:Kernel@What-27s+Here].
+ *  - Inherits from {class BasicObject}[rdoc-ref:BasicObject@Whats+Here].
+ *  - Includes {module Kernel}[rdoc-ref:Kernel@Whats+Here].
  *
  *  Here, class \Object provides methods for:
  *

range.c

@@ -2768,8 +2768,8 @@ range_overlap(VALUE range, VALUE other)
  *
  * First, what's elsewhere. Class \Range:
  *
- * - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- * - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ * - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ * - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
  *   which provides dozens of additional methods.
  *
  * Here, class \Range provides methods that are useful for:

set.c

@@ -2051,8 +2051,8 @@ rb_set_size(VALUE set)
  *
  * First, what's elsewhere. \Class \Set:
  *
- * - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- * - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ * - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ * - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
  *   which provides dozens of additional methods.
  *
  * In particular, class \Set does not have many methods of its own

string.c

@@ -12174,8 +12174,8 @@ rb_str_unicode_normalized_p(int argc, VALUE *argv, VALUE str)
  *
  * First, what's elsewhere. Class +Symbol+:
  *
- * - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- * - Includes {module Comparable}[rdoc-ref:Comparable@What-27s+Here].
+ * - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ * - Includes {module Comparable}[rdoc-ref:Comparable@Whats+Here].
  *
  * Here, class +Symbol+ provides methods that are useful for:
  *

struct.c

@@ -2134,8 +2134,8 @@ rb_data_inspect(VALUE s)
  *
  *  First, what's elsewhere. Class \Struct:
  *
- *  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
- *  - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ *  - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+ *  - Includes {module Enumerable}[rdoc-ref:Enumerable@Whats+Here],
  *    which provides dozens of additional methods.
  *
  *  See also Data, which is a somewhat similar, but stricter concept for defining immutable

test/ruby/test_thread.rb

@@ -1664,4 +1664,37 @@ def test_mn_threads_sub_millisecond_sleep
       assert_operator elapsed, :>=, 0.1, "sub-millisecond sleeps should not return immediately"
     end;
   end
+
+  # [Bug #21840]
+  def test_mutex_owner_doesnt_starve_waiters
+    assert_ruby_status([], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      m = Mutex.new
+
+      fib = lambda { |n|
+        return n if n <= 1
+        fib(n - 1) + fib(n - 2)
+      }
+
+      t1_running = false
+      t1 = Thread.new do
+        t1_running = true
+        loop do
+          fib(20)
+          m.synchronize do
+            File.open(__FILE__) { } # reset timeslice due to blocking operation
+          end
+        end
+      end
+
+      loop until t1_running
+
+      3.times.map do
+        Thread.new do
+          m.synchronize do
+          end
+        end
+      end.each(&:join)
+    end;
+  end
 end

thread_sync.c

@@ -10,6 +10,8 @@ typedef struct rb_mutex_struct {
     rb_thread_t *th; // even if the fiber is collected, we might need access to the thread in mutex_free
     struct rb_mutex_struct *next_mutex;
     struct ccan_list_head waitq; /* protected by GVL */
+    uint32_t saved_running_time_us;
+    bool wait_waking; // Is there a thread waiting to be woken up by this mutex? Reset during every wakeup.
 } rb_mutex_t;
 
 /* sync_waiter is always on-stack */
@@ -212,8 +214,15 @@ mutex_locked(rb_mutex_t *mutex, rb_thread_t *th, rb_serial_t ec_serial)
 static inline bool
 do_mutex_trylock(rb_mutex_t *mutex, rb_thread_t *th, rb_serial_t ec_serial)
 {
+    // NOTE: we can successfully lock a mutex even if there are other threads waiting on it. First one to it wins.
     if (mutex->ec_serial == 0) {
         RUBY_DEBUG_LOG("%p ok", mutex);
+        if (mutex->wait_waking) {
+            // If we acquired `mutex` without contention and before the thread that was popped off the waitq, we're going
+            // to set our running_time back to what it was here during mutex unlock if it got reset during our critical
+            // section. This is to prevent starvation of other threads waiting on the mutex.
+            mutex->saved_running_time_us = th->running_time_us;
+        }
 
         mutex_locked(mutex, th, ec_serial);
         return true;
@@ -350,7 +359,8 @@ do_mutex_lock(struct mutex_args *args, int interruptible_p)
                 }
                 ccan_list_del(&sync_waiter.node);
 
-                // unlocked by another thread while sleeping
+                // If mutex->ec_serial != 0, the mutex was locked by another thread before we had the chance to acquire it.
+                // We'll put ourselves on the waitq and sleep again.
                 if (!mutex->ec_serial) {
                     mutex_set_owner(mutex, th, ec_serial);
                 }
@@ -391,6 +401,7 @@ do_mutex_lock(struct mutex_args *args, int interruptible_p)
 
         if (saved_ints) th->ec->interrupt_flag = saved_ints;
         if (mutex->ec_serial == ec_serial) mutex_locked(mutex, th, ec_serial);
+        mutex->wait_waking = false;
     }
 
     RUBY_DEBUG_LOG("%p locked", mutex);
@@ -454,6 +465,15 @@ rb_mutex_unlock_th(rb_mutex_t *mutex, rb_thread_t *th, rb_serial_t ec_serial)
 
     struct sync_waiter *cur = 0, *next;
 
+
+    if (mutex->wait_waking) {
+        uint32_t saved = mutex->saved_running_time_us;
+        if (th->running_time_us < saved) {
+            th->running_time_us = saved;
+        }
+    }
+
+    mutex->saved_running_time_us = 0;
     mutex->ec_serial = 0;
     thread_mutex_remove(th, mutex);
 
@@ -469,6 +489,7 @@ rb_mutex_unlock_th(rb_mutex_t *mutex, rb_thread_t *th, rb_serial_t ec_serial)
               case THREAD_RUNNABLE: /* from someone else calling Thread#run */
               case THREAD_STOPPED_FOREVER: /* likely (rb_mutex_lock) */
                 RUBY_DEBUG_LOG("wakeup th:%u", rb_th_serial(cur->th));
+                mutex->wait_waking = true;
                 rb_threadptr_interrupt(cur->th);
                 return NULL;
               case THREAD_STOPPED: /* probably impossible */
@@ -480,7 +501,6 @@ rb_mutex_unlock_th(rb_mutex_t *mutex, rb_thread_t *th, rb_serial_t ec_serial)
             }
         }
     }
-
     // We did not find any threads to wake up, so we can just return with no error:
     return NULL;
 }

timev.rb

@@ -170,8 +170,8 @@
 #
 # First, what's elsewhere. Class +Time+:
 #
-# - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
-# - Includes {module Comparable}[rdoc-ref:Comparable@What-27s+Here].
+# - Inherits from {class Object}[rdoc-ref:Object@Whats+Here].
+# - Includes {module Comparable}[rdoc-ref:Comparable@Whats+Here].
 #
 # Here, class +Time+ provides methods that are useful for:
 #