[Draft] Limit length of System.Runtime.BigInteger to int.MaxValue-32 bits

[speshuric]

See discussion in #84670

• Limit BigInteger.MaxLength to int.MaxValue/32 uints. This is equal to limit length in bits to int.MaxValue-32 bits
• Fix ctor BigInteger(ReadOnlySpan<byte>, bool, bool) to check MaxLength limit
• Fix private ctor BigInteger(ReadOnlySpan<uint>, bool) to check MaxLength limit after trying to conserve space, not before
• Fix private ctor BigInteger(Span<uint>) to check MaxLength limit after trying to conserve space, not before
• Fix obsolete comment in AssertValid()
• Fix test LargeNegativeBigIntegerShiftTest to respect new limit.

fix#84670

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Issue Details

---

See discussion in #84670

• Limit BigInteger.MaxLength to int.MaxValue/32 uints. This is equal to limit length in bits to int.MaxValue-32 bits
• Fix ctor BigInteger(ReadOnlySpan<byte>, bool, bool) to check MaxLength limit
• Fix private ctor BigInteger(ReadOnlySpan<uint>, bool) to check MaxLength limit after trying to conserve space, not before
• Fix private ctor BigInteger(Span<uint>) to check MaxLength limit after trying to conserve space, not before
• Fix obsolete comment in AssertValid()
• Fix test LargeNegativeBigIntegerShiftTest to respect new limit.

fix #84670

Author:	speshuric
Assignees:	-
Labels:	area-System.Numerics, community-contribution
Milestone:	-

[huoyaoyuan]

The overflow guard in DebuggerDisplay can also be updated.

[speshuric]

The overflow guard in DebuggerDisplay can also be updated.

Thank you for point that! I'll check it.

[tannergooding]

Is this still being worked on? I'd ideally like to get this one merged prior to #84733 or #83951

[speshuric]

Is this still being worked on? I'd ideally like to get this one merged prior to #84733 or #83951

Sorry, I have been busy a bit. I'll commit the rest of changes this week.

[adamsitnik]

I'll commit the rest of changes this week.

Thank you for your help, there is absolutely no rush from our side.

I am going to apply "need author action" label so this PR is not listed on our internal list of PRs awaiting for review.

[ghost]

This pull request has been automatically marked no-recent-activity because it has not had any activity for 14 days. It will be closed if no further activity occurs within 14 more days. Any new comment (by anyone, not necessarily the author) will remove no-recent-activity.

[speshuric]

I still plan to complete this.

[ghost]

This pull request has been automatically marked no-recent-activity because it has not had any activity for 14 days. It will be closed if no further activity occurs within 14 more days. Any new comment (by anyone, not necessarily the author) will remove no-recent-activity.

[ghost]

This pull request will now be closed since it had been marked no-recent-activity but received no further activity in the past 14 days. It is still possible to reopen or comment on the pull request, but please note that it will be locked if it remains inactive for another 30 days.