From 0469e0afac455049c65ab0a1b047d65e78de1c0a Mon Sep 17 00:00:00 2001
From: Marko Lahma <marko.lahma@gmail.com>
Date: Thu, 14 Nov 2024 20:14:26 +0200
Subject: [PATCH] Detect double.PositiveInfinity when parsing dates on full
 framework

---
 Jint.Tests/Runtime/NumberTests.cs | 18 ++++++++++++++++--
 Jint/Runtime/TypeConverter.cs     | 20 +++++++++++++++++++-
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/Jint.Tests/Runtime/NumberTests.cs b/Jint.Tests/Runtime/NumberTests.cs
index 63e82052b..ec68bb4af 100644
--- a/Jint.Tests/Runtime/NumberTests.cs
+++ b/Jint.Tests/Runtime/NumberTests.cs
@@ -137,11 +137,25 @@ public void ToLocaleString(string parseNumber, string culture, string result)
     }
 
     [Theory]
-    // Does not add extra zeros of there is no cuture argument.
+    // Does not add extra zeros of there is no culture argument.
     [InlineData("123456")]
     public void ToLocaleStringNoArg(string parseNumber)
     {
         var value = _engine.Evaluate($"({parseNumber}).toLocaleString()").AsString();
         Assert.DoesNotContain(".0", value);
     }
-}
\ No newline at end of file
+
+    [Fact]
+    public void CoercingFromString()
+    {
+        var engine = new Engine();
+
+        Assert.Equal(double.PositiveInfinity, engine.Evaluate("Number(1e1000)").ToObject());
+        Assert.Equal(double.PositiveInfinity, engine.Evaluate("+1e1000").ToObject());
+        Assert.Equal("Infinity", engine.Evaluate("(+1e1000).toString()").ToObject());
+
+        Assert.Equal(double.PositiveInfinity, engine.Evaluate("Number('1e1000')").ToObject());
+        Assert.Equal(double.PositiveInfinity, engine.Evaluate("+'1e1000'").ToObject());
+        Assert.Equal("Infinity", engine.Evaluate("(+'1e1000').toString()").ToObject());
+    }
+}
diff --git a/Jint/Runtime/TypeConverter.cs b/Jint/Runtime/TypeConverter.cs
index f11ec3d98..46bafdcbf 100644
--- a/Jint/Runtime/TypeConverter.cs
+++ b/Jint/Runtime/TypeConverter.cs
@@ -274,12 +274,30 @@ private static double ToNumber(string input)
             }
         }
 
+#if NETFRAMEWORK
+        // if we are on full framework, one extra check for whether it was actually over the bounds of double
+        // in modern NET parsing was fixed to be IEEE 754 compliant, full framework is not and cannot detect positive infinity
+        try
+        {
+            var n = double.Parse(input, NumberStyles.AllowDecimalPoint | NumberStyles.AllowExponent, CultureInfo.InvariantCulture);
+            return n == 0 && firstChar == '-' ? -0.0 : n;
+        }
+        catch (Exception e) when (e is OverflowException)
+        {
+            return double.PositiveInfinity;
+        }
+        catch
+        {
+            return double.NaN;
+        }
+#else
         if (double.TryParse(input, NumberStyles, CultureInfo.InvariantCulture, out var n))
         {
             return n == 0 && firstChar == '-' ? -0.0 : n;
         }
 
         return double.NaN;
+#endif
     }
 
     /// <summary>
@@ -1014,4 +1032,4 @@ public static void CheckObjectCoercible(Engine engine, JsValue o)
             ExceptionHelper.ThrowTypeError(engine.Realm, "Cannot call method on " + o);
         }
     }
-}
\ No newline at end of file
+}