Add more information about the decoding errors

[mdb1]

@gentilijuanmanuel I found the piece of code I was looking for:

import Foundation

// sourcery: AutoMockable
// Represents object that is able to log decoding errors in details
protocol DecodingErrorLogging: AnyObject {
    /// This method is used to debug decoding failures
    /// - Parameters:
    ///   - error: Error to log information on
    ///   - type: Type that decoding was attempted for
    func logAdditionalDecodingFailureInfo(with error: Error, for type: Decodable.Type)
}

/// Class that logs error on decoding network models
final class DecodingErrorLogger: DecodingErrorLogging {
    private let jsonDecoder: JSONDecoding
    private let loggerService: Logging

    init(
        jsonDecoder: JSONDecoding = BFJSONDecoder(keyDecodingStrategy: .convertFromSnakeCase),
        loggerService: Logging = NetworkingServiceLocator.logger
    ) {
        self.jsonDecoder = jsonDecoder
        self.loggerService = loggerService
    }

    func logAdditionalDecodingFailureInfo(with error: Error, for type: Decodable.Type) {
        var errorDescription: String?
        var logProperties: [LoggerPropertyKeys: String] = [:]

        if let decodingError = error as? DecodingError {
            switch decodingError {
            case let .dataCorrupted(context):
                // An indication that the data is corrupted or otherwise invalid.
                addContext(context, logProperties: &logProperties)
                errorDescription = LoggerPropertyKeys.dataCorrupted.rawValue
            case let .keyNotFound(key, context):
                // An indication that a keyed decoding container was asked for an entry for the given key,
                // but did not contain one.
                addContext(context, logProperties: &logProperties)
                errorDescription = "Key '\(key)' not found"
            case let .valueNotFound(value, context):
                // An indication that a non-optional value of the given type was expected, but a null value was found.
                addContext(context, logProperties: &logProperties)
                errorDescription = "Value '\(value)' not found"
            case let .typeMismatch(type, context):
                // An indication that a value of the given type could not be decoded because
                // it did not match the type of what was found in the encoded payload.
                addContext(context, logProperties: &logProperties)
                errorDescription = "Type '\(type)' mismatch"
            default: ()
            }
        }
        logProperties[.decodingError] = errorDescription ?? error.localizedDescription
        logProperties[.model] = "\(type)"

        // Log as warning so the information reaches AppCenter Crash reports
        loggerService.log(.warn, .decodingFailure, properties: logProperties)
    }
}

private extension DecodingErrorLogger {
    /// Add Decoding Error context information to the dictionary
    func addContext(
        _ context: DecodingError.Context,
        logProperties: inout [LoggerPropertyKeys: String]
    ) {
        logProperties[.contextProperty] = context.debugDescription
        logProperties[.codingPathProperty] = context.codingPath.debugDescription
        logProperties[.underlyingErrorProperty] = context.underlyingError.debugDescription
    }
}

Is something like that, basically, it prints more information about the particular error in the decoding phase.

Maybe we can add something similar to this to this package 😄