Reduce duplicated warnings for the change of Ruby 3 keyword arguments

By this change, the following code prints only one warning.

```
def foo(**opt); end
100.times { foo({kw:1}) }
```

A global variable `st_table *caller_to_callees` is a map from caller to
a set of callee methods.  It remembers that a warning is already printed
for each pair of caller and callee.

[Feature #16289]

4 files changed, 203 insertions, 41 deletions

diff --git a/test/ruby/test_keyword.rb b/test/ruby/test_keyword.rb
index 862b6733ea..295b499530 100644
--- a/test/ruby/test_keyword.rb
+++ b/test/ruby/test_keyword.rb
@@ -313,9 +313,19 @@ class TestKeywordArguments < Test::Unit::TestCase
 
     sc = Class.new
     c = sc.new
-    def c.m(*args, **kw)
-      super
+    redef = -> do
+      if defined?(c.m)
+        class << c
+          remove_method(:m)
+        end
+      end
+      eval <<-END
+        def c.m(*args, **kw)
+          super(*args, **kw)
+        end
+      END
     end
+    redef[]
     sc.class_eval do
       def m(*args)
         args
@@ -350,6 +360,7 @@ class TestKeywordArguments < Test::Unit::TestCase
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal(kw, c.m(**{}))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal(kw, c.m(**kw))
     end
@@ -386,24 +397,31 @@ class TestKeywordArguments < Test::Unit::TestCase
         [arg, args]
       end
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       c.m(**{})
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       c.m(**kw)
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h, kw], c.m(**h))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h, kw], c.m(a: 1))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h2, kw], c.m(**h2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h3, kw], c.m(**h3))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h3, kw], c.m(a: 1, **h2))
     end
@@ -431,9 +449,19 @@ class TestKeywordArguments < Test::Unit::TestCase
 
     sc = Class.new
     c = sc.new
-    def c.m(*args, **kw)
-      super(*args, **kw)
+    redef = -> do
+      if defined?(c.m)
+        class << c
+          remove_method(:m)
+        end
+      end
+      eval <<-END
+        def c.m(*args, **kw)
+          super(*args, **kw)
+        end
+      END
     end
+    redef[]
     sc.class_eval do
       def m(*args)
         args
@@ -468,6 +496,7 @@ class TestKeywordArguments < Test::Unit::TestCase
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal(kw, c.m(**{}))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal(kw, c.m(**kw))
     end
@@ -504,24 +533,31 @@ class TestKeywordArguments < Test::Unit::TestCase
         [arg, args]
       end
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       c.m(**{})
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       c.m(**kw)
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h, kw], c.m(**h))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h, kw], c.m(a: 1))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h2, kw], c.m(**h2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h3, kw], c.m(**h3))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h3, kw], c.m(a: 1, **h2))
     end
@@ -2092,13 +2128,19 @@ class TestKeywordArguments < Test::Unit::TestCase
     assert_raise(ArgumentError) { c.m(**h3) }
     assert_raise(ArgumentError) { c.m(a: 1, **h2) }
 
-    c.singleton_class.remove_method(:method_missing)
-    def c.method_missing(_, args)
-      args
+    redef = -> do
+      c.singleton_class.remove_method(:method_missing)
+      eval <<-END
+        def c.method_missing(_, args)
+          args
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal(kw, c.m(**{}))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal(kw, c.m(**kw))
     end
@@ -2127,28 +2169,39 @@ class TestKeywordArguments < Test::Unit::TestCase
       assert_raise(ArgumentError) { c.m(h3) }
     end
 
-    c.singleton_class.remove_method(:method_missing)
-    def c.method_missing(_, arg, **args)
-      [arg, args]
+    redef = -> do
+      c.singleton_class.remove_method(:method_missing)
+      eval <<-END
+        def c.method_missing(_, arg, **args)
+          [arg, args]
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([kw, kw], c.m(**{}))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([kw, kw], c.m(**kw))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h, kw], c.m(**h))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h, kw], c.m(a: 1))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h2, kw], c.m(**h2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h3, kw], c.m(**h3))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h3, kw], c.m(a: 1, **h2))
     end
@@ -2950,6 +3003,12 @@ class TestKeywordArguments < Test::Unit::TestCase
     assert_equal([1, h1], o.baz(1, h1))
     assert_equal([h1], o.baz(h1, **{}))
 
+    c.class_eval do
+      remove_method(:bar)
+      def bar(*args, **kw)
+        [args, kw]
+      end
+    end
     assert_warn(/The last argument is used as the keyword parameter.* for `bar'/m) do
       assert_equal([[1], h1], o.foo(:pass_bar, 1, :a=>1))
     end
@@ -4601,13 +4660,19 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
     assert_raise(ArgumentError) { c.call(**h3, &:m) }
     assert_raise(ArgumentError) { c.call(a: 1, **h2, &:m) }
 
-    c.singleton_class.remove_method(:m)
-    def c.m(args)
-      args
+    redef = -> do
+      c.singleton_class.remove_method(:m)
+      eval <<-END
+        def c.m(args)
+          args
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal(kw, c.call(**{}, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal(kw, c.call(**kw, &:m))
     end
@@ -4636,28 +4701,39 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
       assert_raise(ArgumentError) { c.call(h3, &:m) }
     end
 
-    c.singleton_class.remove_method(:m)
-    def c.m(arg, **args)
-      [arg, args]
+    redef = -> do
+      c.singleton_class.remove_method(:m)
+      eval <<-END
+        def c.m(arg, **args)
+          [arg, args]
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([kw, kw], c.call(**{}, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([kw, kw], c.call(**kw, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h, kw], c.call(**h, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h, kw], c.call(a: 1, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h2, kw], c.call(**h2, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h3, kw], c.call(**h3, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `m'/m) do
       assert_equal([h3, kw], c.call(a: 1, **h2, &:m))
     end
@@ -4704,13 +4780,19 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
     assert_raise(ArgumentError) { c.call(**h3, &:m) }
     assert_raise(ArgumentError) { c.call(a: 1, **h2, &:m) }
 
-    c.singleton_class.remove_method(:method_missing)
-    def c.method_missing(_, args)
-      args
+    redef = -> do
+      c.singleton_class.remove_method(:method_missing)
+      eval <<-END
+        def c.method_missing(_, args)
+          args
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal(kw, c.call(**{}, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal(kw, c.call(**kw, &:m))
     end
@@ -4739,28 +4821,39 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
       assert_raise(ArgumentError) { c.call(h3, &:m2) }
     end
 
-    c.singleton_class.remove_method(:method_missing)
-    def c.method_missing(_, arg, **args)
-      [arg, args]
+    redef = -> do
+      c.singleton_class.remove_method(:method_missing)
+      eval <<-END
+        def c.method_missing(_, arg, **args)
+          [arg, args]
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([kw, kw], c.call(**{}, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([kw, kw], c.call(**kw, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h, kw], c.call(**h, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h, kw], c.call(a: 1, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h2, kw], c.call(**h2, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h3, kw], c.call(**h3, &:m))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h3, kw], c.call(a: 1, **h2, &:m))
     end
@@ -4807,13 +4900,19 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
     assert_raise(ArgumentError) { c.call(**h3, &:m2) }
     assert_raise(ArgumentError) { c.call(a: 1, **h2, &:m2) }
 
-    c.singleton_class.remove_method(:method_missing)
-    def c.method_missing(_, args)
-      args
+    redef = -> do
+      c.singleton_class.remove_method(:method_missing)
+      eval <<-END
+        def c.method_missing(_, args)
+          args
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal(kw, c.call(**{}, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal(kw, c.call(**kw, &:m2))
     end
@@ -4842,28 +4941,39 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
       assert_raise(ArgumentError) { c.call(h3, &:m2) }
     end
 
-    c.singleton_class.remove_method(:method_missing)
-    def c.method_missing(_, arg, **args)
-      [arg, args]
+    redef = -> do
+      c.singleton_class.remove_method(:method_missing)
+      eval <<-END
+        def c.method_missing(_, arg, **args)
+          [arg, args]
+        end
+      END
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([kw, kw], c.call(**{}, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([kw, kw], c.call(**kw, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h, kw], c.call(**h, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h, kw], c.call(a: 1, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h2, kw], c.call(**h2, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h3, kw], c.call(**h3, &:m2))
     end
+    redef[]
     assert_warn(/The keyword argument is passed as the last hash parameter.* for `method_missing'/m) do
       assert_equal([h3, kw], c.call(a: 1, **h2, &:m2))
     end
diff --git a/test/ruby/test_struct.rb b/test/ruby/test_struct.rb
index 2f5ef80c9b..884fbe00ed 100644
--- a/test/ruby/test_struct.rb
+++ b/test/ruby/test_struct.rb
@@ -113,7 +113,8 @@ module TestStruct
     assert_equal @Struct::KeywordInitTrue.new(a: 1, b: 2).values, @Struct::KeywordInitFalse.new(1, 2).values
     assert_equal "#{@Struct}::KeywordInitFalse", @Struct::KeywordInitFalse.inspect
     assert_equal "#{@Struct}::KeywordInitTrue(keyword_init: true)", @Struct::KeywordInitTrue.inspect
-    k = Class.new(@Struct::KeywordInitFalse) {def initialize(**) end}
+    # eval is neede to prevent the warning duplication filter
+    k = eval("Class.new(@Struct::KeywordInitFalse) {def initialize(**) end}")
     assert_warn(/The last argument is used as the keyword parameter/) {k.new(a: 1, b: 2)}
     k = Class.new(@Struct::KeywordInitTrue) {def initialize(**) end}
     assert_warn('') {k.new(a: 1, b: 2)}
diff --git a/vm_args.c b/vm_args.c
index 6729d54af7..c46b3cf2a4 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -585,9 +585,56 @@ ignore_keyword_hash_p(VALUE keyword_hash, const rb_iseq_t * const iseq) {
 
 VALUE rb_iseq_location(const rb_iseq_t *iseq);
 
+/* -- Remove In 3.0 -- */
+
+/* This is a map from caller PC to a set of callee methods.
+ * When a warning about keyword argument change is printed,
+ * it keeps the pair of callee and caller.
+ */
+static st_table *caller_to_callees = 0;
+
+static VALUE rb_warn_check(const rb_execution_context_t * const ec, const void *const callee)
+{
+    const rb_control_frame_t * const cfp = rb_vm_get_ruby_level_next_cfp(ec, ec->cfp);
+
+    if (!cfp) return 0;
+
+    const void *const caller = cfp->pc;
+
+    if (!caller_to_callees) {
+        caller_to_callees = st_init_numtable();
+    }
+
+    st_data_t val;
+    if (st_lookup(caller_to_callees, (st_data_t) caller, &val)) {
+        st_table *callees;
+
+        if (val & 1) {
+            val &= ~(st_data_t)1;
+            if (val == (st_data_t) callee) return 1; /* already warned */
+
+            callees = st_init_numtable();
+            st_insert(callees, val, 1);
+        }
+        else {
+            callees = (st_table *) val;
+            if (st_is_member(callees, (st_data_t) callee)) return 1; /* already warned */
+        }
+        st_insert(callees, (st_data_t) callee, 1);
+        st_insert(caller_to_callees, (st_data_t) caller, (st_data_t) callees);
+    }
+    else {
+        st_insert(caller_to_callees, (st_data_t) caller, ((st_data_t) callee) | 1);
+    }
+
+    return 0; /* not warned yet for the pair of caller and callee */
+}
+
 static inline void
-rb_warn_keyword_to_last_hash(struct rb_calling_info *calling, const struct rb_call_info *ci, const rb_iseq_t * const iseq)
+rb_warn_keyword_to_last_hash(rb_execution_context_t * const ec, struct rb_calling_info *calling, const struct rb_call_info *ci, const rb_iseq_t * const iseq)
 {
+    if (rb_warn_check(ec, iseq)) return;
+
     VALUE name, loc;
     if (calling->recv == Qundef) {
         rb_warn("The keyword argument is passed as the last hash parameter");
@@ -613,8 +660,10 @@ rb_warn_keyword_to_last_hash(struct rb_calling_info *calling, const struct rb_ca
 }
 
 static inline void
-rb_warn_split_last_hash_to_keyword(struct rb_calling_info *calling, const struct rb_call_info *ci, const rb_iseq_t * const iseq)
+rb_warn_split_last_hash_to_keyword(rb_execution_context_t * const ec, struct rb_calling_info *calling, const struct rb_call_info *ci, const rb_iseq_t * const iseq)
 {
+    if (rb_warn_check(ec, iseq)) return;
+
     VALUE name, loc;
     name = rb_id2str(ci->mid);
     loc = rb_iseq_location(iseq);
@@ -636,8 +685,10 @@ rb_warn_split_last_hash_to_keyword(struct rb_calling_info *calling, const struct
 }
 
 static inline void
-rb_warn_last_hash_to_keyword(struct rb_calling_info *calling, const struct rb_call_info *ci, const rb_iseq_t * const iseq)
+rb_warn_last_hash_to_keyword(rb_execution_context_t * const ec, struct rb_calling_info *calling, const struct rb_call_info *ci, const rb_iseq_t * const iseq)
 {
+    if (rb_warn_check(ec, iseq)) return;
+
     VALUE name, loc;
     name = rb_id2str(ci->mid);
     loc = rb_iseq_location(iseq);
@@ -766,7 +817,7 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
                     }
                 }
                 else {
-                    rb_warn_keyword_to_last_hash(calling, ci, iseq);
+                    rb_warn_keyword_to_last_hash(ec, calling, ci, iseq);
                 }
 	    }
             else if (!remove_empty_keyword_hash && rest_last) {
@@ -789,7 +840,7 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
                     }
                 }
                 else {
-                    rb_warn_keyword_to_last_hash(calling, ci, iseq);
+                    rb_warn_keyword_to_last_hash(ec, calling, ci, iseq);
                 }
 	    }
             else if (!remove_empty_keyword_hash) {
@@ -856,10 +907,10 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
                 }
                 else if (check_only_symbol) {
                     if (keyword_hash != Qnil) {
-                        rb_warn_split_last_hash_to_keyword(calling, ci, iseq);
+                        rb_warn_split_last_hash_to_keyword(ec, calling, ci, iseq);
                     }
                     else {
-                        rb_warn_keyword_to_last_hash(calling, ci, iseq);
+                        rb_warn_keyword_to_last_hash(ec, calling, ci, iseq);
                     }
                 }
             }
@@ -868,15 +919,15 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
                  * def foo(k:1) p [k]; end
                  * foo({k:42}) #=> 42
                  */
-                rb_warn_last_hash_to_keyword(calling, ci, iseq);
+                rb_warn_last_hash_to_keyword(ec, calling, ci, iseq);
                 given_argc--;
             }
             else if (keyword_hash != Qnil) {
-                rb_warn_split_last_hash_to_keyword(calling, ci, iseq);
+                rb_warn_split_last_hash_to_keyword(ec, calling, ci, iseq);
             }
         }
         else if (given_argc == min_argc && kw_flag) {
-            rb_warn_keyword_to_last_hash(calling, ci, iseq);
+            rb_warn_keyword_to_last_hash(ec, calling, ci, iseq);
         }
     }
 
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 94fc7c72bd..9eb349d54e 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -2926,7 +2926,7 @@ vm_call_method_each_type(rb_execution_context_t *ec, rb_control_frame_t *cfp, st
       case VM_METHOD_TYPE_ATTRSET:
         CALLER_SETUP_ARG(cfp, calling, ci);
         if (calling->argc == 1 && calling->kw_splat && RHASH_EMPTY_P(cfp->sp[-1])) {
-            rb_warn_keyword_to_last_hash(calling, ci, NULL);
+            rb_warn_keyword_to_last_hash(ec, calling, ci, NULL);
         }
         else {
             CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);
@@ -3264,7 +3264,7 @@ vm_callee_setup_block_arg(rb_execution_context_t *ec, struct rb_calling_info *ca
 
         CALLER_SETUP_ARG(cfp, calling, ci);
         if (calling->kw_splat && calling->argc == iseq->body->param.lead_num + iseq->body->param.post_num && RHASH_EMPTY_P(cfp->sp[-1])) {
-            rb_warn_keyword_to_last_hash(calling, ci, iseq);
+            rb_warn_keyword_to_last_hash(ec, calling, ci, iseq);
         }
         else {
             CALLER_REMOVE_EMPTY_KW_SPLAT(cfp, calling, ci);