Bug 795745 - Properly report errors for Number.prototype.to* methods when a provided precision is invalid. r=luke

js/src/jsnum.cpp

@@ -789,10 +789,10 @@ ComputePrecisionInRange(JSContext *cx, int minPrecision, int maxPrecision, const
         *precision = int(prec);
         return true;
     }
+
     ToCStringBuf cbuf;
-    char *numStr = IntToCString(&cbuf, *precision);
-    JS_ASSERT(numStr);
-    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_PRECISION_RANGE, numStr);
+    if (char *numStr = NumberToCString(cx, &cbuf, prec, 10))
+        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_PRECISION_RANGE, numStr);
     return false;
 }
 

js/src/tests/ecma_5/Number/conversion-invalid-precision.js

@@ -0,0 +1,46 @@
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommonn.org/licenses/publicdomain/
+ */
+
+var BUGNUMBER = 795745;
+var summary =
+  "Number.prototype.to* should throw a RangeError when passed a bad precision";
+
+print(BUGNUMBER + ": " + summary);
+
+/**************
+ * BEGIN TEST *
+ **************/
+
+function test(method, prec)
+{
+  try
+  {
+    Number.prototype[method].call(0, prec);
+    throw "should have thrown";
+  }
+  catch (e)
+  {
+    assertEq(e instanceof RangeError, true,
+             "expected RangeError for " + method + " with precision " + prec +
+             ", got " + e);
+  }
+}
+
+test("toExponential", -32);
+test("toFixed", -32);
+test("toPrecision", -32);
+
+test("toExponential", 9999999);
+test("toFixed", 9999999);
+test("toPrecision", 9999999);
+
+test("toPrecision", 0);
+
+/******************************************************************************/
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
+
+print("Tests complete");