Fix memorystream local test failure

[alinpahontu2912]

Follow up for #123440

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Pull request overview

This PR fixes a test failure in MemoryStream_CapacityBoundaryChecks by adding explicit validation to throw ArgumentOutOfRangeException when setting the Capacity property to a value exceeding Array.MaxLength. Previously, attempting to set an invalid capacity would result in an OutOfMemoryException during array allocation, but the test expected ArgumentOutOfRangeException.

Changes:

• Added validation in the Capacity setter to throw ArgumentOutOfRangeException before attempting array allocation when the capacity exceeds the maximum allowed array length

[stephentoub]

Has this always resulted in an OOMException, even on .NET Framework? Or did it used to throw an ArgumentException for this, that regressed, and now this is just fixing the regression?

[alinpahontu2912]

I think it results in an OutOfMemoryException because it tries to allocate a capacity larger than what’s possible. There wasn’t a guard before, so it would fail during the allocation rather than throwing an argument exception here.

[stephentoub]

An OOM seems appropriate to me, or at least more consistent, given that even smaller values could produce an OOMException when trying to allocate the array, and there are many other places we allocate arrays without checking against Array.MaxValue. Without a strong reason to make a breaking change here, I don't think we should.

[jozkee]

@stephentoub Position, Seek and SetLength already do a MemStreamMaxLength check to throw AOOREx, we aligned the ctor with those in https://github.com/dotnet/runtime/pull/119089/changes#r2319364701 and this is now aligning Capacity, which we missed in the previous PRs.

[jozkee]

Do you think we shouldn't have done that? This got in in .NET 11 so we could backpedal if we think that's appropriate.

[jozkee]

We don't use ArgumentOutOfRange_Capacity anywhere else in MemoryStream and what we use in other places e.g. ArgumentOutOfRange_StreamLength, includes the maximum array length:

Stream length must be non-negative and less than the maximum array length {0} - origin.

Should we add a new string mentioning that?

[alinpahontu2912]

Can I maybe just use a similar check to here instead of adding a new error string?

runtime/src/libraries/System.Private.CoreLib/src/System/IO/MemoryStream.cs

Line 47 in 2a3cec1

ArgumentOutOfRangeException.ThrowIfGreaterThan(capacity, MemStreamMaxLength);