Make help showable through button on command error message. (#2439)

* Make help showable through button on command error message.

* Improve error message

Improve error message for attempting to delete other users' command invocations

Co-authored-by: Boris Muratov <[email protected]>

* Use double quotes instead of single

* Refactor to use `ViewWithUserAndRoleCheck`

---------

Co-authored-by: Boris Muratov <[email protected]>

2 files changed, 51 insertions, 15 deletions

diff --git a/bot/exts/backend/error_handler.py b/bot/exts/backend/error_handler.py
index faa39db5d..5cf07613d 100644
--- a/bot/exts/backend/error_handler.py
+++ b/bot/exts/backend/error_handler.py
@@ -1,10 +1,12 @@
 import copy
 import difflib
 
-from discord import Embed, Forbidden, Member
+import discord
+from discord import ButtonStyle, Embed, Forbidden, Interaction, Member, User
 from discord.ext.commands import ChannelNotFound, Cog, Context, TextChannelConverter, VoiceChannelConverter, errors
 from pydis_core.site_api import ResponseCodeError
 from pydis_core.utils.error_handling import handle_forbidden_from_block
+from pydis_core.utils.interactions import DeleteMessageButton, ViewWithUserAndRoleCheck
 from sentry_sdk import push_scope
 
 from bot.bot import Bot
@@ -16,6 +18,35 @@ from bot.utils.checks import ContextCheckFailure
 log = get_logger(__name__)
 
 
+class HelpEmbedView(ViewWithUserAndRoleCheck):
+    """View to allow showing the help command for command error responses."""
+
+    def __init__(self, help_embed: Embed, owner: User | Member):
+        super().__init__(allowed_roles=MODERATION_ROLES, allowed_users=[owner.id])
+        self.help_embed = help_embed
+
+        self.delete_button = DeleteMessageButton()
+        self.add_item(self.delete_button)
+
+    async def interaction_check(self, interaction: Interaction) -> bool:
+        """Overriden check to allow anyone to use the help button."""
+        if (interaction.data or {}).get("custom_id") == self.help_button.custom_id:
+            log.trace(
+                "Allowed interaction by %s (%d) on %d as interaction was with the help button.",
+                interaction.user,
+                interaction.user.id,
+                interaction.message.id,
+            )
+            return True
+
+        return await super().interaction_check(interaction)
+
+    @discord.ui.button(label="Help", style=ButtonStyle.primary)
+    async def help_button(self, interaction: Interaction, button: discord.ui.Button) -> None:
+        """Send an ephemeral message with the contents of the help command."""
+        await interaction.response.send_message(embed=self.help_embed, ephemeral=True)
+
+
 class ErrorHandler(Cog):
     """Handles errors emitted from commands."""
 
@@ -117,15 +148,6 @@ class ErrorHandler(Cog):
             # ExtensionError
             await self.handle_unexpected_error(ctx, e)
 
-    async def send_command_help(self, ctx: Context) -> None:
-        """Return a prepared `help` command invocation coroutine."""
-        if ctx.command:
-            self.bot.help_command.context = ctx
-            await ctx.send_help(ctx.command)
-            return
-
-        await ctx.send_help()
-
     async def try_silence(self, ctx: Context) -> bool:
         """
         Attempt to invoke the silence or unsilence command if invoke with matches a pattern.
@@ -300,8 +322,21 @@ class ErrorHandler(Cog):
             )
             self.bot.stats.incr("errors.other_user_input_error")
 
-        await ctx.send(embed=embed)
-        await self.send_command_help(ctx)
+        await self.send_error_with_help(ctx, embed)
+
+    async def send_error_with_help(self, ctx: Context, error_embed: Embed) -> None:
+        """Send error message, with button to show command help."""
+        # Fall back to just sending the error embed if the custom help cog isn't loaded yet.
+        # ctx.command shouldn't be None here, but check just to be safe.
+        help_embed_creator = getattr(self.bot.help_command, "command_formatting", None)
+        if not help_embed_creator or not ctx.command:
+            await ctx.send(embed=error_embed)
+            return
+
+        self.bot.help_command.context = ctx
+        help_embed, _ = await help_embed_creator(ctx.command)
+        view = HelpEmbedView(help_embed, ctx.author)
+        view.message = await ctx.send(embed=error_embed, view=view)
 
     @staticmethod
     async def handle_check_failure(ctx: Context, e: errors.CheckFailure) -> None:
diff --git a/tests/bot/exts/backend/test_error_handler.py b/tests/bot/exts/backend/test_error_handler.py
index 9670d42a0..dbc62270b 100644
--- a/tests/bot/exts/backend/test_error_handler.py
+++ b/tests/bot/exts/backend/test_error_handler.py
@@ -414,12 +414,13 @@ class IndividualErrorHandlerTests(unittest.IsolatedAsyncioTestCase):
         for case in test_cases:
             with self.subTest(error=case["error"], call_prepared=case["call_prepared"]):
                 self.ctx.reset_mock()
+                self.cog.send_error_with_help = AsyncMock()
                 self.assertIsNone(await self.cog.handle_user_input_error(self.ctx, case["error"]))
-                self.ctx.send.assert_awaited_once()
                 if case["call_prepared"]:
-                    self.ctx.send_help.assert_awaited_once()
+                    self.cog.send_error_with_help.assert_awaited_once()
                 else:
-                    self.ctx.send_help.assert_not_awaited()
+                    self.ctx.send.assert_awaited_once()
+                    self.cog.send_error_with_help.assert_not_awaited()
 
     async def test_handle_check_failure_errors(self):
         """Should await `ctx.send` when error is check failure."""