(based on a conversation I had with @labath yesterday in
https://github.com/llvm/llvm-project/pull/106442)
Most APIs that currently vend a Status would be better served by
returning llvm::Expected<> instead. If possibles APIs should be
refactored to avoid Status. The only legitimate long-term uses of Status
are objects that need to store an error for a long time (which should be
questioned as a design decision, too).
This patch makes the transition to llvm::Error easier by making the
places that cannot switch to llvm::Error explicit: They are marked with
a call to Status::clone(). Every other API can and should be refactored
to use llvm::Expected. In the end Status should only be used in very few
places.
Whenever an unchecked Error is dropped by Status it logs this to the
verbose API channel.
Implementation notes:
This patch introduces two new kinds of error_category as well as new
llvm::Error types. Here is the mapping of lldb::ErrorType to
llvm::Errors:
```
(eErrorTypeInvalid)
eErrorTypeGeneric llvm::StringError
eErrorTypePOSIX llvm::ECError
eErrorTypeMachKernel MachKernelError
eErrorTypeExpression llvm::ErrorList<ExpressionError>
eErrorTypeWin32 Win32Error
```
Test for both IPv4 and IPv6 support to determine if either `127.0.0.1` or `[::1]` are appropriate IP addresses to attempt to connect to. In an IPv6-only environment, `127.0.0.1` is not available.
Using `localhost` is problematic because we might not be able to get the same port on each IP flavor, and later try to connect to the wrong thing.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D133393
Our (TCP) socket support is in a much better state than pipes. Use that
for testing the Communication class.
Move the CreateTCPConnectedSockets function
(SocketTestUtilities.{h,cpp}) to a place where it can be used from
Communication tests.
