merge revision(s) 58471,58493: [Backport #13505]

load.c: backtrace of circular require

	* load.c (load_lock): print backtrace of circular require via
	  `Warning.warn` [ruby-core:80850] [Bug #13505]

	Send the backtrace of the circular require warning as a single String to Warning.warn

	* load.c: send as a single string.
	* error.c: expose the string formatted by rb_warning as rb_warning_string().
	* test/ruby/test_exception.rb: update tests.
	  [ruby-core:80850] [Bug #13505]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@62435 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

error.c

@@ -162,10 +162,16 @@ rb_warning_s_warn(VALUE mod, VALUE str)
     return Qnil;
 }
 
+VALUE
+rb_warning_warn(VALUE mod, VALUE str)
+{
+    return rb_funcallv(mod, id_warn, 1, &str);
+}
+
 static void
 rb_write_warning_str(VALUE str)
 {
-    rb_funcall(rb_mWarning, id_warn, 1, str);
+    rb_warning_warn(rb_mWarning, str);
 }
 
 static VALUE
@@ -254,6 +260,14 @@ rb_warning(const char *fmt, ...)
     }
 }
 
+VALUE
+rb_warning_string(const char *fmt, ...)
+{
+    with_warning_string(mesg, 0, fmt) {
+    }
+    return mesg;
+}
+
 #if 0
 void
 rb_enc_warning(rb_encoding *enc, const char *fmt, ...)

internal.h

@@ -1033,6 +1033,8 @@ VALUE rb_name_err_new(VALUE mesg, VALUE recv, VALUE method);
     rb_name_err_raise_str(rb_fstring_cstr(mesg), (recv), (name))
 NORETURN(void ruby_only_for_internal_use(const char *));
 #define ONLY_FOR_INTERNAL_USE(func) ruby_only_for_internal_use(func)
+VALUE rb_warning_warn(VALUE mod, VALUE str);
+VALUE rb_warning_string(const char *fmt, ...);
 
 /* eval.c */
 VALUE rb_refinement_module_get_refined_class(VALUE module);
@@ -1641,7 +1643,7 @@ void rb_backtrace_print_as_bugreport(void);
 int rb_backtrace_p(VALUE obj);
 VALUE rb_backtrace_to_str_ary(VALUE obj);
 VALUE rb_backtrace_to_location_ary(VALUE obj);
-void rb_backtrace_print_to(VALUE output);
+void rb_backtrace_each(VALUE (*iter)(VALUE recv, VALUE str), VALUE output);
 VALUE rb_vm_backtrace_object(void);
 
 RUBY_SYMBOL_EXPORT_BEGIN

load.c

@@ -720,6 +720,8 @@ rb_f_load(int argc, VALUE *argv)
     return Qtrue;
 }
 
+extern VALUE rb_mWarning;
+
 static char *
 load_lock(const char *ftptr)
 {
@@ -742,8 +744,9 @@ load_lock(const char *ftptr)
 	return (char *)"";
     }
     if (RTEST(ruby_verbose)) {
-	rb_warning("loading in progress, circular require considered harmful - %s", ftptr);
-	rb_backtrace_print_to(rb_stderr);
+	VALUE warning = rb_warning_string("loading in progress, circular require considered harmful - %s", ftptr);
+	rb_backtrace_each(rb_str_append, warning);
+	rb_warning_warn(rb_mWarning, warning);
     }
     switch (rb_thread_shield_wait((VALUE)data)) {
       case Qfalse:

test/ruby/test_exception.rb

@@ -934,23 +934,23 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
     end
   end
 
-  def test_warning_warn
+  def capture_warning_warn
     verbose = $VERBOSE
-    warning = nil
+    warning = []
 
     ::Warning.class_eval do
       alias_method :warn2, :warn
       remove_method :warn
 
       define_method(:warn) do |str|
-        warning = str
+        warning << str
       end
     end
 
     $VERBOSE = true
-    a = @a
+    yield
 
-    assert_match(/instance variable @a not initialized/, warning)
+    return warning
   ensure
     $VERBOSE = verbose
 
@@ -961,6 +961,11 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
     end
   end
 
+  def test_warning_warn
+    warning = capture_warning_warn {@a}
+    assert_match(/instance variable @a not initialized/, warning[0])
+  end
+
   def test_warning_warn_invalid_argument
     assert_raise(TypeError) do
       ::Warning.warn nil
@@ -973,6 +978,27 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
     end
   end
 
+  def test_warning_warn_circular_require_backtrace
+    warning = nil
+    path = nil
+    Tempfile.create(%w[circular .rb]) do |t|
+      begin
+        path = t.path
+        basename = File.basename(path)
+        t.puts "require '#{basename}'"
+        t.close
+        $LOAD_PATH.push(File.dirname(t))
+        warning = capture_warning_warn {require basename}
+      ensure
+        $LOAD_PATH.pop
+        $LOADED_FEATURES.delete(t)
+      end
+    end
+    assert_equal(1, warning.size)
+    assert_match(/circular require/, warning.first)
+    assert_match(/^\tfrom #{Regexp.escape(path)}:1:/, warning.first)
+  end
+
   def test_undefined_backtrace
     assert_separately([], "#{<<-"begin;"}\n#{<<-"end;"}")
     begin;

version.h

@@ -1,10 +1,10 @@
 #define RUBY_VERSION "2.4.4"
-#define RUBY_RELEASE_DATE "2018-02-16"
-#define RUBY_PATCHLEVEL 236
+#define RUBY_RELEASE_DATE "2018-02-17"
+#define RUBY_PATCHLEVEL 237
 
 #define RUBY_RELEASE_YEAR 2018
 #define RUBY_RELEASE_MONTH 2
-#define RUBY_RELEASE_DAY 16
+#define RUBY_RELEASE_DAY 17
 
 #include "ruby/version.h"
 

vm_backtrace.c

@@ -778,10 +778,15 @@ rb_backtrace(void)
     vm_backtrace_print(stderr);
 }
 
+struct print_to_arg {
+    VALUE (*iter)(VALUE recv, VALUE str);
+    VALUE output;
+};
+
 static void
 oldbt_print_to(void *data, VALUE file, int lineno, VALUE name)
 {
-    VALUE output = (VALUE)data;
+    const struct print_to_arg *arg = data;
     VALUE str = rb_sprintf("\tfrom %"PRIsVALUE":%d:in ", file, lineno);
 
     if (NIL_P(name)) {
@@ -790,16 +795,19 @@ oldbt_print_to(void *data, VALUE file, int lineno, VALUE name)
     else {
 	rb_str_catf(str, " `%"PRIsVALUE"'\n", name);
     }
-    rb_io_write(output, str);
+    (*arg->iter)(arg->output, str);
 }
 
 void
-rb_backtrace_print_to(VALUE output)
+rb_backtrace_each(VALUE (*iter)(VALUE recv, VALUE str), VALUE output)
 {
     struct oldbt_arg arg;
+    struct print_to_arg parg;
 
+    parg.iter = iter;
+    parg.output = output;
     arg.func = oldbt_print_to;
-    arg.data = (void *)output;
+    arg.data = &parg;
     backtrace_each(GET_THREAD(),
 		   oldbt_init,
 		   oldbt_iter_iseq,