update docs and errors

Author: kmahar

Sources/MongoSwift/MongoCollection+BulkWrite.swift

@@ -13,7 +13,7 @@ extension MongoCollection {
      *
      * - Throws:
      *   - `MongoError.invalidArgument` if `requests` is empty
-     *   - `MongoError.commandError` if any error occurs while performing the writes
+     *   - `MongoError.bulkWriteError` if any error occurs while performing the writes
      */
     @discardableResult
     public func bulkWrite(_ requests: [WriteModel], options: BulkWriteOptions? = nil) throws -> BulkWriteResult? {

Sources/MongoSwift/MongoCollection+FindAndModify.swift

@@ -10,6 +10,9 @@ extension MongoCollection {
      *   - options: Optional `FindOneAndDeleteOptions` to use when executing the command
      *
      * - Returns: The deleted document, represented as a `CollectionType`, or `nil` if no document was deleted.
+     * - Throws: 
+     *   - `MongoError.commandError` if there are any errors executing the command.
+     *   - A `DecodingError` if the deleted document cannot be decoded to a `CollectionType` value
      */
     @discardableResult
     public func findOneAndDelete(_ filter: Document, options: FindOneAndDeleteOptions? = nil) throws -> CollectionType? {
@@ -26,6 +29,10 @@ extension MongoCollection {
      *
      * - Returns: A `CollectionType`, representing either the original document or its replacement,
      *      depending on selected options, or `nil` if there was no match.
+     * - Throws: 
+     *   - `MongoError.commandError` if there are any errors executing the command.
+     *   - An `EncodingError` if `replacement` cannot be encoded to a `Document`
+     *   - A `DecodingError` if the replaced document cannot be decoded to a `CollectionType` value
      */
     @discardableResult
     public func findOneAndReplace(filter: Document, replacement: CollectionType,
@@ -43,6 +50,9 @@ extension MongoCollection {
      *
      * - Returns: A `CollectionType` representing either the original or updated document,
      *      depending on selected options, or `nil` if there was no match.
+     * - Throws: 
+     *   - `MongoError.commandError` if there are any errors executing the command.
+     *   - A `DecodingError` if the updated document cannot be decoded to a `CollectionType` value
      */
     @discardableResult
     public func findOneAndUpdate(filter: Document, update: Document,

Sources/MongoSwift/MongoError.swift

@@ -24,9 +24,13 @@ public enum MongoError {
     /// Thrown when there is an error involving a `ReadConcern`. 
     case readConcernError(message: String)
     /// Thrown when there is an error involving a `WriteConcern`. 
-    case writeConcernError(message: String)
+    case writeConcernError(code: Int32, message: String)
     /// Thrown when a user-provided argument is invalid.
     case invalidArgument(message: String)
+    /// Thrown when there is an error executing a write command.
+    case writeError(code: Int32, message: String)
+    /// Thrown when there is an error executing a bulk write command. 
+    indirect case bulkWriteError(code: Int32, message: String, result: BulkWriteResult?, writeErrors: [MongoError]?, writeConcernError: MongoError?)
 }
 
 /// An extension of `MongoError` to support printing out descriptive error messages.
@@ -37,8 +41,11 @@ extension MongoError: LocalizedError {
             let .invalidCollection(message), let .commandError(message),
             let .bsonParseError(_, _, message), let .bsonEncodeError(message),
             let .typeError(message), let .readConcernError(message),
-            let .writeConcernError(message):
+            let .invalidArgument(message):
             return message
+        case let .writeConcernError(code, message), let .writeError(code, message),
+            let .bulkWriteError(code, message, _, _, _):
+            return "\(message) (error code \(code))"
         default:
             return nil
         }

Sources/MongoSwift/WriteConcern.swift

@@ -128,7 +128,7 @@ public class WriteConcern: Codable {
             let journalStr = String(describing: journal)
             let wStr = String(describing: w)
             let timeoutStr = String(describing: wtimeoutMS)
-            throw MongoError.writeConcernError(message:
+            throw MongoError.writeConcernError(code: 0, message:
                 "Invalid combination of WriteConcern options: journal=\(journalStr), w=\(wStr), wtimeoutMS=\(timeoutStr)")
         }
     }