load.c: backtrace of circular require

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

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58471 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 53 insertions, 12 deletions

diff --git a/error.c b/error.c
index e431a6f9b9..45106de851 100644
--- a/error.c
+++ b/error.c
@@ -145,10 +145,16 @@ 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
diff --git a/internal.h b/internal.h
index afea318376..0988f301dd 100644
--- a/internal.h
+++ b/internal.h
@@ -1139,6 +1139,7 @@ VALUE rb_name_err_new(VALUE mesg, VALUE recv, VALUE method);
 NORETURN(void ruby_deprecated_internal_feature(const char *));
 #define DEPRECATED_INTERNAL_FEATURE(func) \
     (ruby_deprecated_internal_feature(func), UNREACHABLE)
+VALUE rb_warning_warn(VALUE mod, VALUE str);
 
 /* eval.c */
 VALUE rb_refinement_module_get_refined_class(VALUE module);
@@ -1749,7 +1750,7 @@ 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);
 
 RUBY_SYMBOL_EXPORT_BEGIN
 const char *rb_objspace_data_type_name(VALUE obj);
diff --git a/load.c b/load.c
index 5adef7cdd0..cba2763749 100644
--- a/load.c
+++ b/load.c
@@ -719,6 +719,8 @@ rb_f_load(int argc, VALUE *argv)
     return Qtrue;
 }
 
+extern VALUE rb_mWarning;
+
 static char *
 load_lock(const char *ftptr)
 {
@@ -742,7 +744,7 @@ load_lock(const char *ftptr)
     }
     if (RTEST(ruby_verbose)) {
 	rb_warning("loading in progress, circular require considered harmful - %s", ftptr);
-	rb_backtrace_print_to(rb_stderr);
+	rb_backtrace_each(rb_warning_warn, rb_mWarning);
     }
     switch (rb_thread_shield_wait((VALUE)data)) {
       case Qfalse:
diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index 1179c26c51..8a8edd2ff2 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -943,23 +943,23 @@ $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
 
@@ -970,6 +970,11 @@ $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
@@ -982,6 +987,25 @@ $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|
+      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
+    assert_match(/circular require/, warning.first)
+    warning.pop while %r[lib/rubygems/core_ext/kernel_require.rb:] =~ warning.last
+    assert_operator(warning.last, :start_with?, "\tfrom #{path}:1:")
+  end
+
   def test_undefined_backtrace
     assert_separately([], "#{<<-"begin;"}\n#{<<-"end;"}")
     begin;
diff --git a/vm_backtrace.c b/vm_backtrace.c
index 6a5dadf709..a5ab52e349 100644
--- a/vm_backtrace.c
+++ b/vm_backtrace.c
@@ -772,10 +772,15 @@ 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)) {
@@ -784,16 +789,19 @@ 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,