Add RedisError parsing and usage

Author: Mordil

Sources/NIORedis/Coders/RedisDataDecoder.swift

@@ -61,7 +61,15 @@ extension RedisDataDecoder {
             return try _parseBulkString(at: &position, from: buffer)
         case .asterisk:
             return try _parseArray(at: &position, from: buffer)
-        default: return .notYetParsed
+        case .hyphen:
+            guard let string = try _parseSimpleString(at: &position, from: buffer) else { return .notYetParsed }
+            let error = RedisError(identifier: "serverSide", reason: string)
+            return .parsed
+        default:
+            throw RedisError(
+                identifier: "invalidTokenType",
+                reason: "Unexpected error while parsing Redis RESP."
+            )
         }
     }
 
@@ -101,8 +109,10 @@ extension RedisDataDecoder {
         guard let string = try _parseSimpleString(at: &position, from: buffer) else { return nil }
 
         guard let number = Int(string) else {
-            #warning("TODO: Throw errors")
-            return nil
+            throw RedisError(
+                identifier: "parseInteger",
+                reason: "Unexpected error while parsing Redis RESP."
+            )
         }
 
         return number

Sources/NIORedis/RedisError.swift

@@ -0,0 +1,20 @@
+import Foundation
+
+/// Errors thrown while working with Redis.
+public struct RedisError: CustomDebugStringConvertible, CustomStringConvertible, LocalizedError {
+    public private(set) var description: String
+    public private(set) var debugDescription: String
+
+    public init(
+        identifier: String,
+        reason: String,
+        file: String = #file,
+        function: String = #function,
+        line: UInt = #line,
+        column: UInt = #column
+    ) {
+        let name = String(describing: type(of: self))
+        description = "⚠️ [\(name).\(identifier): \(reason)]"
+        debugDescription = "⚠️ Redis Error: \(reason)\n- id: \(name).\(identifier)\n\n\(Thread.callStackSymbols)"
+    }
+}

Tests/NIORedisTests/RedisDataDecoder+ParsingTests.swift

@@ -53,6 +53,13 @@ final class RedisDataDecoderParsingTests: XCTestCase {
         try parseTest_recursive(withChunks: ["*-1\r".convertedToData(), "\n".convertedToData()])
     }
 
+    func testParsing_withInvalidSymbol_throws() {
+        var buffer = allocator.buffer(capacity: 1)
+        buffer.write(string: "&3\r\n")
+        var position = 0
+        XCTAssertNil(try? RedisDataDecoder()._parse(at: &position, from: buffer))
+    }
+
     /// See parse_Test_singleValue(input:) String
     private func parseTest_singleValue(input: String) throws {
         try parseTest_singleValue(input: input.convertedToData())
@@ -298,6 +305,7 @@ extension RedisDataDecoderParsingTests {
         ("testParsing_with_bulkString_recursively", testParsing_with_bulkString_recursively),
         ("testParsing_with_arrays", testParsing_with_arrays),
         ("testParsing_with_arrays_recursively", testParsing_with_arrays_recursively),
+        ("testParsing_withInvalidSymbol_throws", testParsing_withInvalidSymbol_throws),
         ("testParsing_simpleString_missingEndings_returnsNil", testParsing_simpleString_missingEndings_returnsNil),
         ("testParsing_simpleString_withNoContent_returnsEmpty", testParsing_simpleString_withNoContent_returnsEmpty),
         ("testParsing_simpleString_withContent_returnsExpectedContent", testParsing_simpleString_withContent_returnsExpectedContent),