generalize stream empty to argument empty

lbry/error/README.md

@@ -25,7 +25,6 @@ Message | User friendly error message explaining the exceptional event. Supports
 Code | Name | Message
 ---:|---|---
 **1xx** | UserInput | User input errors.
-111 | EmptyStreamName | Stream name cannot be blank.
 **10x** | Command | Errors preparing to execute commands.
 101 | CommandDoesNotExist | Command '{command}' does not exist.
 102 | CommandDeprecated | Command '{command}' is deprecated.
@@ -36,6 +35,7 @@ Code | Name | Message
 111 | GenericInputValue | The value '{value}' for argument '{argument}' is not valid.
 112 | InputValueIsNone | None or null is not valid value for argument '{argument}'.
 113 | ConflictingInputValue | Only '{first_argument}' or '{second_argument}' is allowed, not both.
+114 | InputStringIsBlank | {argument} cannot be blank.
 **2xx** | Configuration | Configuration errors.
 201 | ConfigWrite | Cannot write configuration file '{path}'. -- When writing the default config fails on startup, such as due to permission issues.
 202 | ConfigRead | Cannot find provided configuration file '{path}'. -- Can't open the config file user provided via command line args.

lbry/error/__init__.py

@@ -7,12 +7,6 @@ class UserInputError(BaseError):
     """
 
 
-class EmptyStreamNameError(UserInputError):
-
-    def __init__(self):
-        super().__init__("Stream name cannot be blank.")
-
-
 class CommandError(UserInputError):
     """
     Errors preparing to execute commands.
@@ -90,6 +84,13 @@ class ConflictingInputValueError(InputValueError):
         super().__init__(f"Only '{first_argument}' or '{second_argument}' is allowed, not both.")
 
 
+class InputStringIsBlankError(InputValueError):
+
+    def __init__(self, argument):
+        self.argument = argument
+        super().__init__(f"{argument} cannot be blank.")
+
+
 class ConfigurationError(BaseError):
     """
     Configuration errors.

lbry/extras/daemon/daemon.py

@@ -38,7 +38,7 @@ from lbry.dht.peer import make_kademlia_peer
 from lbry.error import (
     DownloadSDTimeoutError, ComponentsNotStartedError, ComponentStartConditionNotMetError,
     CommandDoesNotExistError, BaseError, WalletNotFoundError, WalletAlreadyLoadedError, WalletAlreadyExistsError,
-    ConflictingInputValueError, AlreadyPurchasedError, PrivateKeyNotFoundError, EmptyStreamNameError
+    ConflictingInputValueError, AlreadyPurchasedError, PrivateKeyNotFoundError, InputStringIsBlankError
 )
 from lbry.extras import system_info
 from lbry.extras.daemon import analytics
@@ -5242,7 +5242,7 @@ class Daemon(metaclass=JSONRPCServerType):
     def valid_stream_name_or_error(name: str):
         try:
             if not name:
-                raise EmptyStreamNameError()
+                raise InputStringIsBlankError('Stream name')
             parsed = URL.parse(name)
             if parsed.has_channel:
                 # TODO: use error from lbry.error