Try to improve mmm_description for cases where NSError is transformed

NSError crossing concurrency domains (thrown from an async function) appears to
be replaced with a native implementation with different runtime type affecting
the current logic of mmm_description which would use regular description for
Swift-native errors. A workaround for now is to check for code not being -1.

MMMCommonCore.podspec

@@ -6,7 +6,7 @@
 Pod::Spec.new do |s|
 
 	s.name = "MMMCommonCore"
-	s.version = "1.16.1"
+	s.version = "1.16.2"
 	s.summary = "Small bits and pieces reused in many pods from MMMTemple"
 	s.description =  s.summary
 	s.homepage = "https://github.com/mediamonks/#{s.name}"

Sources/MMMCommonCore/CommonCore.swift

@@ -65,17 +65,14 @@ private struct PairsIterator<Iterator: IteratorProtocol>: IteratorProtocol {
 // MARK: -
 
 extension Error {
+
 	/// Better string representation for `Error` and `NSError`s.
 	///
 	/// This is a Swift version of `mmm_description` that allows to avoid casting to `NSError`
 	/// and which falls back `String(describing:)` for "not really" `NSError`s to avoid meaningless
 	/// "The operation couldn't be completed" messages.
 	public var mmm_description: String {
-		if type(of: self) is NSError.Type {
-			return (self as NSError).mmm_description()
-		} else {
-			return String(describing: self)
-		}
+		(self as NSError).mmm_description()
 	}
 }
 
@@ -193,12 +190,13 @@ public func MMMTypeName(_ value: Any) -> String {
 }
 
 extension NSError {
+
 	/// Initialize using the given value's type name as a domain string.
 	public convenience init(domain: Any, message: String, code: Int = -1, underlyingError: Error? = nil) {
 		var userInfo = [String: Any]()
 		userInfo[NSLocalizedDescriptionKey] = message
-		if let underlyingError = underlyingError as NSError? {
-			userInfo[NSUnderlyingErrorKey] = underlyingError
+		if let underlyingError {
+			userInfo[NSUnderlyingErrorKey] = underlyingError as NSError
 		}
 		let domain = (domain as? String) ?? MMMTypeName(domain)
 		self.init(domain: domain, code: code, userInfo: userInfo)

Sources/MMMCommonCoreObjC/MMMCommonCore.m

@@ -224,11 +224,13 @@ - (NSString *)mmm_description {
 }
 
 - (NSString *)mmm_nonRecursiveDescription {
-	if (self.class == NSClassFromString(@"__SwiftNativeNSError")) {
+	if (self.class == NSClassFromString(@"__SwiftNativeNSError") && self.code != -1) {
 		// Treating underlying Swift errors as NSError is normally useless and it's better to fall back to their descriptions instead.
 		// (I could check for `self.class != NSError.class` here to make it less dependent on the actual system class name,
 		// but that would include rare subclasses like `NSURLError`; I could also check for "Swift" in the class name, but that still
 		// would not guarantee to cover future changes in the standard library anyway.)
+		// Update: now we have to check for code not being -1 as `NSError` are now translated into Swift ones when
+		// crossing concurrency domains.
 		return [self description];
 	} else {
 		// Treating the -1 error code as "other" kind of error, where only the message matters for diagnostics.