Limit the ext cog to 1 action at a time (#2205)

1 files changed, 26 insertions, 15 deletions

diff --git a/bot/exts/utils/extensions.py b/bot/exts/utils/extensions.py
index 0f5fc0de4..90249867f 100644
--- a/bot/exts/utils/extensions.py
+++ b/bot/exts/utils/extensions.py
@@ -34,6 +34,7 @@ class Extensions(commands.Cog):
 
     def __init__(self, bot: Bot):
         self.bot = bot
+        self.action_in_progress = False
 
     @group(name="extensions", aliases=("ext", "exts", "c", "cog", "cogs"), invoke_without_command=True)
     async def extensions_group(self, ctx: Context) -> None:
@@ -54,8 +55,7 @@ class Extensions(commands.Cog):
         if "*" in extensions or "**" in extensions:
             extensions = set(self.bot.all_extensions) - set(self.bot.extensions.keys())
 
-        msg = await self.batch_manage(Action.LOAD, *extensions)
-        await ctx.send(msg)
+        await self.batch_manage(Action.LOAD, ctx, *extensions)
 
     @extensions_group.command(name="unload", aliases=("ul",))
     async def unload_command(self, ctx: Context, *extensions: Extension) -> None:
@@ -71,14 +71,12 @@ class Extensions(commands.Cog):
         blacklisted = "\n".join(UNLOAD_BLACKLIST & set(extensions))
 
         if blacklisted:
-            msg = f":x: The following extension(s) may not be unloaded:```\n{blacklisted}```"
+            await ctx.send(f":x: The following extension(s) may not be unloaded:```\n{blacklisted}```")
         else:
             if "*" in extensions or "**" in extensions:
                 extensions = set(self.bot.extensions.keys()) - UNLOAD_BLACKLIST
 
-            msg = await self.batch_manage(Action.UNLOAD, *extensions)
-
-        await ctx.send(msg)
+            await self.batch_manage(Action.UNLOAD, ctx, *extensions)
 
     @extensions_group.command(name="reload", aliases=("r",), root_aliases=("reload",))
     async def reload_command(self, ctx: Context, *extensions: Extension) -> None:
@@ -100,9 +98,7 @@ class Extensions(commands.Cog):
             extensions = set(self.bot.extensions.keys()) | set(extensions)
             extensions.remove("*")
 
-        msg = await self.batch_manage(Action.RELOAD, *extensions)
-
-        await ctx.send(msg)
+        await self.batch_manage(Action.RELOAD, ctx, *extensions)
 
     @extensions_group.command(name="list", aliases=("all",))
     async def list_command(self, ctx: Context) -> None:
@@ -151,17 +147,27 @@ class Extensions(commands.Cog):
 
         return categories
 
-    async def batch_manage(self, action: Action, *extensions: str) -> str:
+    async def batch_manage(self, action: Action, ctx: Context, *extensions: str) -> None:
         """
-        Apply an action to multiple extensions and return a message with the results.
+        Apply an action to multiple extensions, giving feedback to the invoker while doing so.
 
         If only one extension is given, it is deferred to `manage()`.
         """
+        if self.action_in_progress:
+            await ctx.send(":x: Another action is in progress, please try again later.")
+            return
+
+        verb = action.name.lower()
+
+        self.action_in_progress = True
+        loading_message = await ctx.send(f":hourglass_flowing_sand: {verb} in progress, please wait...")
+
         if len(extensions) == 1:
             msg, _ = await self.manage(action, extensions[0])
-            return msg
+            await loading_message.edit(content=msg)
+            self.action_in_progress = False
+            return
 
-        verb = action.name.lower()
         failures = {}
 
         for extension in extensions:
@@ -178,7 +184,8 @@ class Extensions(commands.Cog):
 
         log.debug(f"Batch {verb}ed extensions.")
 
-        return msg
+        await loading_message.edit(content=msg)
+        self.action_in_progress = False
 
     async def manage(self, action: Action, ext: str) -> t.Tuple[str, t.Optional[str]]:
         """Apply an action to an extension and return the status message and any error message."""
@@ -215,7 +222,11 @@ class Extensions(commands.Cog):
 
     # This cannot be static (must have a __func__ attribute).
     async def cog_command_error(self, ctx: Context, error: Exception) -> None:
-        """Handle BadArgument errors locally to prevent the help command from showing."""
+        """Handle errors locally to prevent the error handler cog from interfering when not wanted."""
+        # Safely clear the flag on unexpected errors to avoid deadlocks.
+        self.action_in_progress = False
+
+        # Handle BadArgument errors locally to prevent the help command from showing.
         if isinstance(error, commands.BadArgument):
             await ctx.send(str(error))
             error.handled = True