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Fix ArgumentOutOfRangeException when using DateTime.MinValue/MaxValue with timezone offsets #843

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Merged
sebastienros merged 5 commits into from
Oct 24, 2025
Merged

Fix ArgumentOutOfRangeException when using DateTime.MinValue/MaxValue with timezone offsets #843

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eb3cf49
Initial plan
Copilot Oct 24, 2025
c242c53
Add DateTime constructor to DateTimeValue to handle MinValue/MaxValue…
Copilot Oct 24, 2025
5c159a4
Clean up unnecessary culture backup/restore code in tests
Copilot Oct 24, 2025
710c03e
Handle overflow for DateTime values near MinValue/MaxValue using try-…
Copilot Oct 24, 2025
4b66dc8
Optimize DateTime constructor to only use try-catch near boundaries
Copilot Oct 24, 2025
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40 changes: 40 additions & 0 deletions Fluid.Tests/TemplateTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -285,6 +285,46 @@ public async Task ShouldEvaluateTimeSpanValue()
Assert.Equal("1970-01-01 01:00:00Z", result);
}

[Fact]
public async Task ShouldHandleDateTimeMinValueWithPositiveTimezoneOffset()
{
// Set a timezone offset of +2 hours (like EET - Eastern European Time)
var plusTwoTimezone = TimeZoneInfo.CreateCustomTimeZone("Custom+2", TimeSpan.FromHours(2), "UTC+2", "UTC+2");

_parser.TryParse("{{ foo }} {{ date }}", out var template, out var error);

var context = new TemplateContext { TimeZone = plusTwoTimezone };
context.SetValue("foo", "bar");
context.SetValue("date", DateTime.MinValue);
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@sebastienros sebastienros Oct 24, 2025

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@copilot what it the value is DateTime.MinValue + 1hour, there would still be an exception. The constructor need to check if there is an overflow, not just special values like MinValue and MaxValue.

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Copilot AI Oct 24, 2025

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Updated the implementation to use a try-catch approach instead of checking for exact MinValue/MaxValue. Now handles any DateTime value that would cause overflow when converted to DateTimeOffset, including cases like DateTime.MinValue + 1 hour.

Added tests for these scenarios:

  • DateTime.MinValue + 1 hour with +2 offset
  • DateTime.MaxValue - 1 hour with -2 offset

Fixed in commit 710c03e


// This should not throw ArgumentOutOfRangeException
var result = await template.RenderAsync(context);

// DateTime.MinValue should be rendered as the minimum DateTimeOffset value
Assert.Contains("bar", result);
Assert.Contains("0001-01-01", result);
}

[Fact]
public async Task ShouldHandleDateTimeMaxValueWithNegativeTimezoneOffset()
{
// Set a timezone offset of -2 hours (like Brazil Standard Time)
var minusTwoTimezone = TimeZoneInfo.CreateCustomTimeZone("Custom-2", TimeSpan.FromHours(-2), "UTC-2", "UTC-2");

_parser.TryParse("{{ foo }} {{ date }}", out var template, out var error);

var context = new TemplateContext { TimeZone = minusTwoTimezone };
context.SetValue("foo", "bar");
context.SetValue("date", DateTime.MaxValue);

// This should not throw ArgumentOutOfRangeException
var result = await template.RenderAsync(context);

// DateTime.MaxValue should be rendered as the maximum DateTimeOffset value
Assert.Contains("bar", result);
Assert.Contains("9999-12-31", result);
}

[Fact]
public async Task ShouldEvaluateObjectProperty()
{
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22 changes: 22 additions & 0 deletions Fluid/Values/DateTimeValue.cs
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Expand Up @@ -13,6 +13,28 @@ public DateTimeValue(DateTimeOffset value)
_value = value;
}

public DateTimeValue(DateTime value)
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@sebastienros sebastienros Oct 24, 2025 •
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@copilot Check for values less than one day of the boundaries before doing the try/catch. Otherwise just do the conversion directly.

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@sebastienros sebastienros Oct 24, 2025

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@copilot Check for values less than one day of the boundaries before doing the try/catch. Otherwise just do the conversion directly.

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Copilot AI Oct 24, 2025

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Optimized the implementation to check if the value is within one day of the boundaries before using try-catch. Normal DateTime values now use direct conversion without exception overhead, while values near MinValue/MaxValue still use try-catch to handle potential overflow.

Fixed in commit 4b66dc8

{
// Handle edge cases where DateTime.MinValue or DateTime.MaxValue
// cannot be safely converted to DateTimeOffset with local timezone offset

if (value == DateTime.MinValue)
{
// Use DateTimeOffset.MinValue to avoid offset issues
_value = DateTimeOffset.MinValue;
}
else if (value == DateTime.MaxValue)
{
// Use DateTimeOffset.MaxValue to avoid offset issues
_value = DateTimeOffset.MaxValue;
}
else
{
// Normal conversion - implicit conversion uses local timezone for Unspecified kind
_value = value;
}
}

public override FluidValues Type => FluidValues.DateTime;

public override bool Equals(FluidValue other)
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