Tar: support GNU numeric format.

[tmds]

The tar specification stores numeric fields using an octal representation. This limits the range of values that can be stored.

To increase the supported range, a GNU extension defines that when the leading byte is 0xff/0x80 the remaining bytes are a negative/positive big endian formatted value.

When writing under the PAX format, we continue to only use the only octal representation in the header fields. The values are overridden using extended attributes.

Fixes #93763.

@dotnet/area-system-formats-tar ptal.

[tmds]

Test failures are unrelated.

[tmds]

@dotnet/area-system-formats-tar ptal.

[tmds]

@carlossanlop ptal.

[tmds]

@dotnet/area-system-formats-tar ptal.

[am11]

It would be nice to get this in for .NET 9. The sooner tar implementation matures the better for the ecosystem. Thanks for this @tmds! 👍

[carlossanlop]

Thanks for this change. I left some questions. Haven't gone through the whole PR yet.

We also need to run runtime-extra-platforms tests.

[carlossanlop]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[tmds]

@carlossanlop I have addressed your feedback, can you take another look?

[carlossanlop]

Thank you for addressing the feedback. I gave it another pass and left some comments for you to consider.

I'll run runtime-extra-platforms now to see if we catch any unexpected errors.

[carlossanlop]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[tmds]

@carlossanlop I've addressed the additional feedback except for the writerbig test. See #101172 (comment).

[tmds]

@carlossanlop can you let me know if you want this test included: #101172 (comment)?

[carlossanlop]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[carlossanlop]

Approved pending two things:

• The re-addition of the removed writer-big test case as suggested in the snippet.
• I ran runtime-extra-platforms, which executes tar tests in many other platforms (mobile maybe). Please verify we don't see any new failures related to this change.

[tmds]

@carlossanlop can you start another run of runtime-extra-platforms?

[carlossanlop]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[tmds]

@carlossanlop this is good to merge.

[carlossanlop]

Thanks @tmds!

[carlossanlop]

Considering this is a problem that can be seen in runfo (one of our infrastructure tools) I'm inclined to backport this to .NET 8. Would you have any objections, @ericstj?

[ericstj]

Runfo isn't a critical tool, its just for debugging. I'd instead suggest you seek out input from customers reporting this one. See if anyone is blocked on .NET 8.0 - that's more important. This definitely would meet the bar for servicing if we had a customer blocked by it.