Introduce a debug mode that logs all first-chance exceptions

[KirillOsenkov]

Introduce a trait/environment variable which, when turned on, would subscribe to AppDomain.CurrentDomain.FirstChanceExceptions event and log messages for each first-chance exception happening in each process. This would be verbose, but could help catch really difficult issues where we have 0 errors, 0 warnings but the build failed.

See more inspiration and details here:
https://twitter.com/KirillOsenkov/status/1469388468824330241

and here:
https://github.com/KirillOsenkov/Bliki/wiki/First-chance-exceptions

[elachlan]

Can't use https://github.com/benaadams/Ben.Demystifier because it has an Apache license. Also MSBuild probably doesn't want another external dependency.

So something similar to Demystifier may need to be written from scratch.

Sounds like a cool idea!

[KirillOsenkov]

Certainly not worth an external dependency. But even vanilla would go a long way for debugging purposes.

[KirillOsenkov]

Ideally log as a message into the logging service, with the nodeid, but probably can't have projectid, targetid or taskid.
This way all first-chance exceptions will be in the binlog. We should log the full stack trace, potentially deduplicate by storing 10 last stacks and avoid logging if we've seen it before.