[SR-7652] Error bridged to NSError's description doesn't use my CustomStringConvertible instance's description

[weissi]

Previous ID	SR-7652
Radar	None
Original Reporter	@weissi
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Standard Library
Labels	Bug, Runtime
Assignee	@theblixguy
Priority	Medium

md5: 839f0bcd698aa191bfb33d06fa2cd5ce

Issue Description:

from a very recent Swift 4.2 snapshot on Darwin:

  1> import Foundation
  2> struct MyError: Error, CustomStringConvertible { let description = "this is the right description" }
  3> print((MyError() as NSError).description)
Error Domain=__lldb_expr_3.MyError Code=1 "(null)"

I think this definitely should print the description of MyError instead of the not so useful default NSError description

[lorentey]

I think we should provide a custom implementation for -[_SwiftNativeNSError description] in the runtime, calling swift::getDescription on the native error value.

[weissi]

this is still an issue:

  8> print(IOError(errnoCode: 2, function: "foo") as NSError)
Error Domain=NIO.IOError Code=1 "(null)"
  9> print(IOError(errnoCode: 2, function: "foo"))
foo failed: No such file or directory (errno: 2)

[theblixguy]

#29224

[theblixguy]

Fixed on master. Please verify using the next available snapshot!