merge revision(s) 61525,61527,63062,63650: [Backport #14846]

	error.c: negative uplevel

	* error.c (rb_warn_m): negative uplevel is not allowed.
	  [ruby-core:84568] [Bug #14262]

	error.c: limit depth

	* error.c (rb_warn_m): limit backtrace depth to reduce objects to
	  be created but not used.

	error.c: prepend "warning: " always

	* error.c (rb_warn_m): prepend the string "warning: " if uplevel
	  keyword is given, even if caller file and line information are
	  not available.

	Fix condition in Kernel#warn when using uplevel

	* It causes SEGV on `warn("foo", uplevel: 100)`.
	* Found in a ruby/spec added by @andrykonchin in
	  https://github.com/ruby/spec/pull/605

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@63819 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 19 insertions, 10 deletions

diff --git a/error.c b/error.c
index 3f2dccd2d4..442f6ebffc 100644
--- a/error.c
+++ b/error.c
@@ -327,11 +327,11 @@ warning_write(int argc, VALUE *argv, VALUE buf)
 static VALUE
 rb_warn_m(int argc, VALUE *argv, VALUE exc)
 {
-    VALUE opts, uplevel = Qnil;
+    VALUE opts, location = Qnil;
 
     if (!NIL_P(ruby_verbose) && argc > 0 &&
 	    (argc = rb_scan_args(argc, argv, "*:", NULL, &opts)) > 0) {
-	VALUE str = argv[0];
+	VALUE str = argv[0], uplevel = Qnil;
 	if (!NIL_P(opts)) {
 	    static ID kwds[1];
 	    if (!kwds[0]) {
@@ -342,23 +342,32 @@ rb_warn_m(int argc, VALUE *argv, VALUE exc)
 		uplevel = Qnil;
 	    }
 	    else if (!NIL_P(uplevel)) {
-		uplevel = LONG2NUM((long)NUM2ULONG(uplevel) + 1);
-		uplevel = rb_vm_thread_backtrace_locations(1, &uplevel, GET_THREAD()->self);
-		if (!NIL_P(uplevel)) {
-		    uplevel = rb_ary_entry(uplevel, 0);
+		VALUE args[2];
+		long lev = NUM2LONG(uplevel);
+		if (lev < 0) {
+		    rb_raise(rb_eArgError, "negative level (%ld)", lev);
+		}
+		args[0] = LONG2NUM(lev + 1);
+		args[1] = INT2FIX(1);
+		location = rb_vm_thread_backtrace_locations(2, args, GET_THREAD()->self);
+		if (!NIL_P(location)) {
+		    location = rb_ary_entry(location, 0);
 		}
 	    }
 	}
 	if (argc > 1 || !NIL_P(uplevel) || !end_with_asciichar(str, '\n')) {
+	    VALUE path;
 	    if (NIL_P(uplevel)) {
 		str = rb_str_tmp_new(0);
 	    }
+	    else if (NIL_P(location) ||
+		     NIL_P(path = rb_funcall(location, rb_intern("path"), 0))) {
+		str = rb_str_new_cstr("warning: ");
+	    }
 	    else {
-		VALUE path;
-		path = rb_funcall(uplevel, rb_intern("path"), 0);
-		str = rb_sprintf("%s:%li: warning: ",
+		str = rb_sprintf("%s:%ld: warning: ",
 		    rb_string_value_ptr(&path),
-		    NUM2LONG(rb_funcall(uplevel, rb_intern("lineno"), 0)));
+		    NUM2LONG(rb_funcall(location, rb_intern("lineno"), 0)));
 	    }
 	    RBASIC_SET_CLASS(str, rb_cWarningBuffer);
 	    rb_io_puts(argc, argv, str);