From 2eb4fd22728afe62063a7b3ec77adf9c57ac6d09 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor.andersson@artifex.com>
Date: Wed, 3 Feb 2021 17:18:28 +0100
Subject: [PATCH] Bug 703459: Handle undefined argument to Error constructor.

---
 jserror.c | 4 +---
 jsrepr.c  | 7 ++++---
 main.c    | 7 +++++--
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/jserror.c b/jserror.c
index b3a71f0..c454157 100644
--- a/jserror.c
+++ b/jserror.c
@@ -57,9 +57,8 @@ static void Ep_toString(js_State *J)
 
 static int jsB_ErrorX(js_State *J, js_Object *prototype)
 {
-	int top = js_gettop(J);
 	js_pushobject(J, jsV_newobject(J, JS_CERROR, prototype));
-	if (top > 1) {
+	if (js_isdefined(J, 1)) {
 		js_pushstring(J, js_tostring(J, 1));
 		js_defproperty(J, -2, "message", JS_DONTENUM);
 	}
@@ -109,7 +108,6 @@ void jsB_initerror(js_State *J)
 	js_pushobject(J, J->Error_prototype);
 	{
 			jsB_props(J, "name", "Error");
-			jsB_props(J, "message", "an error has occurred");
 			jsB_propf(J, "Error.prototype.toString", Ep_toString, 0);
 	}
 	js_newcconstructor(J, jsB_Error, jsB_Error, "Error", 1);
diff --git a/jsrepr.c b/jsrepr.c
index 9074f2a..8d63222 100644
--- a/jsrepr.c
+++ b/jsrepr.c
@@ -220,9 +220,10 @@ static void reprvalue(js_State *J, js_Buffer **sb)
 			js_puts(J, sb, js_tostring(J, -1));
 			js_pop(J, 1);
 			js_putc(J, sb, '(');
-			js_getproperty(J, -1, "message");
-			reprstr(J, sb, js_tostring(J, -1));
-			js_pop(J, 1);
+			if (js_hasproperty(J, -1, "message")) {
+				reprvalue(J, sb);
+				js_pop(J, 1);
+			}
 			js_puts(J, sb, "))");
 			break;
 		case JS_CMATH:
diff --git a/main.c b/main.c
index 7535c81..bbc5f2f 100644
--- a/main.c
+++ b/main.c
@@ -220,10 +220,13 @@ static const char *require_js =
 	"require.cache = Object.create(null);\n"
 ;
 
+
 static const char *stacktrace_js =
 	"Error.prototype.toString = function() {\n"
-	"if (this.stackTrace) return this.name + ': ' + this.message + this.stackTrace;\n"
-	"return this.name + ': ' + this.message;\n"
+	"var s = this.name;\n"
+	"if ('message' in this) s += ': ' + this.message;\n"
+	"if ('stackTrace' in this) s += this.stackTrace;\n"
+	"return s;\n"
 	"};\n"
 ;