Remove generic exceptions. (#2913)

* Replace instances of Exception with better ones in reflection utils.

* Replace instances of Exception with better ones in the websocket project.

* Finish replacing generic exceptions.

* Tiny tweak to reflection utils for consistency with the .NET library.

experiment/Discord.Net.BuildOverrides/BuildOverrides.cs

@@ -263,7 +263,7 @@ namespace Discord
                 var result = await client.PostAsync($"{ApiUrl}/overrides/{id}/dependency", new StringContent($"{{ \"info\": \"{name}\"}}", Encoding.UTF8, "application/json"));
 
                 if (!result.IsSuccessStatusCode)
-                    throw new Exception("Failed to get dependency");
+                    throw new HttpRequestException("Failed to get dependency");
 
                 using (var ms = new MemoryStream())
                 {

src/Discord.Net.Commands/Utilities/ReflectionUtils.cs

@@ -37,7 +37,7 @@ namespace Discord.Commands
             }
             catch (Exception ex)
             {
-                throw new Exception($"Failed to create \"{ownerType.FullName}\".", ex);
+                throw new TargetInvocationException($"Failed to create \"{ownerType.FullName}\".", ex);
             }
         }
 
@@ -45,7 +45,7 @@ namespace Discord.Commands
         {
             var constructors = ownerType.DeclaredConstructors.Where(x => !x.IsStatic).ToArray();
             if (constructors.Length == 0)
-                throw new InvalidOperationException($"No constructor found for \"{ownerType.FullName}\".");
+                throw new MissingMethodException($"No constructor found for \"{ownerType.FullName}\".");
             else if (constructors.Length > 1)
                 throw new InvalidOperationException($"Multiple constructors found for \"{ownerType.FullName}\".");
             return constructors[0];

src/Discord.Net.Interactions/Utilities/ReflectionUtils.cs

@@ -40,14 +40,14 @@ namespace Discord.Interactions
             }
             catch (Exception ex)
             {
-                throw new Exception($"Failed to create \"{ownerType.FullName}\".", ex);
+                throw new TargetInvocationException($"Failed to create \"{ownerType.FullName}\".", ex);
             }
         }
         private static ConstructorInfo GetConstructor(TypeInfo ownerType)
         {
             var constructors = ownerType.DeclaredConstructors.Where(x => !x.IsStatic).ToArray();
             if (constructors.Length == 0)
-                throw new InvalidOperationException($"No constructor found for \"{ownerType.FullName}\".");
+                throw new MissingMethodException($"No constructor found for \"{ownerType.FullName}\".");
             else if (constructors.Length > 1)
                 throw new InvalidOperationException($"Multiple constructors found for \"{ownerType.FullName}\".");
             return constructors[0];

src/Discord.Net.Rest/Utils/HexConverter.cs

@@ -11,7 +11,7 @@ namespace Discord.Rest
         public static byte[] HexToByteArray(string hex)
         {
             if (hex.Length % 2 == 1)
-                throw new Exception("The binary key cannot have an odd number of digits");
+                throw new ArgumentException("The binary key cannot have an odd number of digits");
 
             byte[] arr = new byte[hex.Length >> 1];
 

src/Discord.Net.WebSocket/Audio/AudioClient.cs

@@ -506,7 +506,7 @@ namespace Discord.Audio
                     if (_heartbeatTimes.Count != 0 && (now - _lastMessageTime) > intervalMillis &&
                         ConnectionState == ConnectionState.Connected)
                     {
-                        _connection.Error(new Exception("Server missed last heartbeat"));
+                        _connection.Error(new WebSocketException(WebSocketError.InvalidState, "Server missed last heartbeat"));
                         return;
                     }
 

src/Discord.Net.WebSocket/Audio/Opus/OpusConverter.cs

@@ -1,4 +1,5 @@
 using System;
+using System.IO;
 
 namespace Discord.Audio
 {
@@ -36,12 +37,12 @@ namespace Discord.Audio
         protected static void CheckError(int result)
         {
             if (result < 0)
-                throw new Exception($"Opus Error: {(OpusError)result}");
+                throw new InvalidDataException($"Opus Error: {(OpusError)result}");
         }
         protected static void CheckError(OpusError error)
         {
             if ((int)error < 0)
-                throw new Exception($"Opus Error: {error}");
+                throw new InvalidDataException($"Opus Error: {error}");
         }
     }
 }

src/Discord.Net.WebSocket/Audio/Sodium/SecretBox.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Runtime.InteropServices;
+using System.Security;
 
 namespace Discord.Audio
 {
@@ -17,7 +18,7 @@ namespace Discord.Audio
             {
                 int error = SecretBoxEasy(outPtr + outputOffset, inPtr + inputOffset, inputLength, nonce, secret);
                 if (error != 0)
-                    throw new Exception($"Sodium Error: {error}");
+                    throw new SecurityException($"Sodium Error: {error}");
                 return inputLength + 16;
             }
         }
@@ -28,7 +29,7 @@ namespace Discord.Audio
             {
                 int error = SecretBoxOpenEasy(outPtr + outputOffset, inPtr + inputOffset, inputLength, nonce, secret);
                 if (error != 0)
-                    throw new Exception($"Sodium Error: {error}");
+                    throw new SecurityException($"Sodium Error: {error}");
                 return inputLength - 16;
             }
         }

src/Discord.Net.WebSocket/ConnectionManager.cs

@@ -1,6 +1,7 @@
 using Discord.Logging;
 using Discord.Net;
 using System;
+using System.Net.WebSockets;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -43,15 +44,16 @@ namespace Discord
                 {
                     var ex2 = ex as WebSocketClosedException;
                     if (ex2?.CloseCode == 4006)
-                        CriticalError(new Exception("WebSocket session expired", ex));
+                        CriticalError(new WebSocketException(WebSocketError.ConnectionClosedPrematurely, "WebSocket session expired", ex));
                     else if (ex2?.CloseCode == 4014)
-                        CriticalError(new Exception("WebSocket connection was closed", ex));
+                        CriticalError(new WebSocketException(WebSocketError.ConnectionClosedPrematurely, "WebSocket connection was closed", ex));
                     else
-                        Error(new Exception("WebSocket connection was closed", ex));
+                        Error(new WebSocketException(WebSocketError.ConnectionClosedPrematurely, "WebSocket connection was closed", ex));
                 }
                 else
-                    Error(new Exception("WebSocket connection was closed"));
+                    Error(new WebSocketException(WebSocketError.ConnectionClosedPrematurely, "WebSocket connection was closed"));
-                return Task.Delay(0);
+
+                return Task.CompletedTask;
             });
         }
 

src/Discord.Net.WebSocket/Net/DefaultWebSocketClient.cs

@@ -267,7 +267,7 @@ namespace Discord.Net.WebSockets
             }
             catch (Win32Exception ex) when (ex.HResult == HR_TIMEOUT)
             {
-                var _ = OnClosed(new Exception("Connection timed out.", ex));
+                var _ = OnClosed(new WebSocketException(WebSocketError.ConnectionClosedPrematurely, "Connection timed out.", ex));
             }
             catch (OperationCanceledException) { }
             catch (Exception ex)

test/Discord.Net.Tests.Integration/DiscordRestClientFixture.cs

@@ -16,7 +16,7 @@ namespace Discord
         {
             var token = Environment.GetEnvironmentVariable("DNET_TEST_TOKEN", EnvironmentVariableTarget.Process);
             if (string.IsNullOrWhiteSpace(token))
-                throw new Exception("The DNET_TEST_TOKEN environment variable was not provided.");
+                throw new ArgumentException("The DNET_TEST_TOKEN environment variable was not provided.");
             Client = new DiscordRestClient(new DiscordRestConfig()
             {
                 LogLevel = LogSeverity.Debug,