Bug: 'unescape' fails at the very line end

[firegurafiku]

Please, have a look at the following REPL session:

Welcome to Jint (1.0.0.0)
Type 'exit' to leave, 'print()' to write on the console, 'load()' to load scripts.

jint> unescape("%40")
=> "%40"
jint> unescape("%40_")
=> "@_"
jint> unescape("%40%40")
=> "@%40"
jint> unescape("%u0040")
=> "%u0040"
jint> unescape("%u0040_")
=> "@_"
jint> unescape("%u0040%u0040")
=> "@%u0040"

It shows that unescape consistently fails to decode a percent-encoded character if it happens just before the end of string.
I believe this behavior is caused by an "off by one" error in the function's implementation loop.

The following patch seems to fix the bug:

diff --git a/Jint/Native/Global/GlobalObject.cs b/Jint/Native/Global/GlobalObject.cs
index de224161..62dd56db 100644
--- a/Jint/Native/Global/GlobalObject.cs
+++ b/Jint/Native/Global/GlobalObject.cs
@@ -676,23 +676,23 @@ namespace Jint.Native.Global

             for (var k = 0; k < strLen; k++)
             {
                 var c = uriString[k];
                 if (c == '%')
                 {
-                    if (k < strLen - 6
+                    if (k <= strLen - 6
                         && uriString[k + 1] == 'u'
                         && uriString.Skip(k + 2).Take(4).All(IsValidHexaChar))
                     {
                         c = (char)int.Parse(
                             string.Join(string.Empty, uriString.Skip(k + 2).Take(4)),
                             NumberStyles.AllowHexSpecifier);

                         k += 5;
                     }
-                    else if (k < strLen - 3
+                    else if (k <= strLen - 3
                         && uriString.Skip(k + 1).Take(2).All(IsValidHexaChar))
                     {
                         c = (char)int.Parse(
                             string.Join(string.Empty, uriString.Skip(k + 1).Take(2)),
                             NumberStyles.AllowHexSpecifier);

HEAD: 6880a99

[lahma]

Thank you for the detailed reproduction and fix. The fix has been merged and will be in the next release (to be released soon to NuGet).