1 files changed, 28 insertions, 8 deletions

diff --git a/core/io/json.cpp b/core/io/json.cpp
index 394cf216e8..82ef2a6894 100644
--- a/core/io/json.cpp
+++ b/core/io/json.cpp
@@ -55,7 +55,7 @@ static String _make_indent(const String &p_indent, int p_size) {
 	return indent_text;
 }
 
-String JSON::_print_var(const Variant &p_var, const String &p_indent, int p_cur_indent, bool p_sort_keys) {
+String JSON::_print_var(const Variant &p_var, const String &p_indent, int p_cur_indent, bool p_sort_keys, Set<const void *> &p_markers, bool p_full_precision) {
 	String colon = ":";
 	String end_statement = "";
 
@@ -71,8 +71,17 @@ String JSON::_print_var(const Variant &p_var, const String &p_indent, int p_cur_
 			return p_var.operator bool() ? "true" : "false";
 		case Variant::INT:
 			return itos(p_var);
-		case Variant::FLOAT:
-			return rtos(p_var);
+		case Variant::FLOAT: {
+			double num = p_var;
+			if (p_full_precision) {
+				// Store unreliable digits (17) instead of just reliable
+				// digits (14) so that the value can be decoded exactly.
+				return String::num(num, 17 - (int)floor(log10(num)));
+			} else {
+				// Store only reliable digits (14) by default.
+				return String::num(num, 14 - (int)floor(log10(num)));
+			}
+		}
 		case Variant::PACKED_INT32_ARRAY:
 		case Variant::PACKED_INT64_ARRAY:
 		case Variant::PACKED_FLOAT32_ARRAY:
@@ -82,20 +91,29 @@ String JSON::_print_var(const Variant &p_var, const String &p_indent, int p_cur_
 			String s = "[";
 			s += end_statement;
 			Array a = p_var;
+
+			ERR_FAIL_COND_V_MSG(p_markers.has(a.id()), "\"[...]\"", "Converting circular structure to JSON.");
+			p_markers.insert(a.id());
+
 			for (int i = 0; i < a.size(); i++) {
 				if (i > 0) {
 					s += ",";
 					s += end_statement;
 				}
-				s += _make_indent(p_indent, p_cur_indent + 1) + _print_var(a[i], p_indent, p_cur_indent + 1, p_sort_keys);
+				s += _make_indent(p_indent, p_cur_indent + 1) + _print_var(a[i], p_indent, p_cur_indent + 1, p_sort_keys, p_markers);
 			}
 			s += end_statement + _make_indent(p_indent, p_cur_indent) + "]";
+			p_markers.erase(a.id());
 			return s;
 		}
 		case Variant::DICTIONARY: {
 			String s = "{";
 			s += end_statement;
 			Dictionary d = p_var;
+
+			ERR_FAIL_COND_V_MSG(p_markers.has(d.id()), "\"{...}\"", "Converting circular structure to JSON.");
+			p_markers.insert(d.id());
+
 			List<Variant> keys;
 			d.get_key_list(&keys);
 
@@ -108,12 +126,13 @@ String JSON::_print_var(const Variant &p_var, const String &p_indent, int p_cur_
 					s += ",";
 					s += end_statement;
 				}
-				s += _make_indent(p_indent, p_cur_indent + 1) + _print_var(String(E->get()), p_indent, p_cur_indent + 1, p_sort_keys);
+				s += _make_indent(p_indent, p_cur_indent + 1) + _print_var(String(E->get()), p_indent, p_cur_indent + 1, p_sort_keys, p_markers);
 				s += colon;
-				s += _print_var(d[E->get()], p_indent, p_cur_indent + 1, p_sort_keys);
+				s += _print_var(d[E->get()], p_indent, p_cur_indent + 1, p_sort_keys, p_markers);
 			}
 
 			s += end_statement + _make_indent(p_indent, p_cur_indent) + "}";
+			p_markers.erase(d.id());
 			return s;
 		}
 		default:
@@ -121,8 +140,9 @@ String JSON::_print_var(const Variant &p_var, const String &p_indent, int p_cur_
 	}
 }
 
-String JSON::print(const Variant &p_var, const String &p_indent, bool p_sort_keys) {
-	return _print_var(p_var, p_indent, 0, p_sort_keys);
+String JSON::print(const Variant &p_var, const String &p_indent, bool p_sort_keys, bool p_full_precision) {
+	Set<const void *> markers;
+	return _print_var(p_var, p_indent, 0, p_sort_keys, markers, p_full_precision);
 }
 
 Error JSON::_get_token(const char32_t *p_str, int &index, int p_len, Token &r_token, int &line, String &r_err_str) {