[Utils] Add filters for spoiler markdown (#2401)

This also wraps some fields of the modlog with the same sanitization, as well as the `[p]names` command.

redbot/core/modlog.py

@@ -6,7 +6,12 @@ import discord
 from redbot.core import Config
 from redbot.core.bot import Red
 
-from .utils.common_filters import filter_invites, filter_mass_mentions, filter_urls
+from .utils.common_filters import (
+    filter_invites,
+    filter_mass_mentions,
+    filter_urls,
+    escape_spoilers,
+)
 
 __all__ = [
     "Case",
@@ -113,8 +118,10 @@ class Case:
             reason = "**Reason:** Use `[p]reason {} <reason>` to add it".format(self.case_number)
 
         if self.moderator is not None:
-            moderator = "{}#{} ({})\n".format(
-                self.moderator.name, self.moderator.discriminator, self.moderator.id
+            moderator = escape_spoilers(
+                "{}#{} ({})\n".format(
+                    self.moderator.name, self.moderator.discriminator, self.moderator.id
+                )
             )
         else:
             moderator = "Unknown"
@@ -131,8 +138,10 @@ class Case:
 
         amended_by = None
         if self.amended_by:
-            amended_by = "{}#{} ({})".format(
-                self.amended_by.name, self.amended_by.discriminator, self.amended_by.id
+            amended_by = escape_spoilers(
+                "{}#{} ({})".format(
+                    self.amended_by.name, self.amended_by.discriminator, self.amended_by.id
+                )
             )
 
         last_modified = None
@@ -141,9 +150,11 @@ class Case:
                 datetime.fromtimestamp(self.modified_at).strftime("%Y-%m-%d %H:%M:%S")
             )
 
-        user = filter_invites(
-            "{}#{} ({})\n".format(self.user.name, self.user.discriminator, self.user.id)
-        )  # Invites get rendered even in embeds.
+        user = escape_spoilers(
+            filter_invites(
+                "{}#{} ({})\n".format(self.user.name, self.user.discriminator, self.user.id)
+            )
+        )  # Invites and spoilers get rendered even in embeds.
         if embed:
             emb = discord.Embed(title=title, description=reason)
 

redbot/core/utils/common_filters.py

@@ -9,6 +9,8 @@ __all__ = [
     "filter_mass_mentions",
     "filter_various_mentions",
     "normalize_smartquotes",
+    "escape_spoilers",
+    "escape_spoilers_and_mass_mentions",
 ]
 
 # regexes
@@ -29,6 +31,10 @@ SMART_QUOTE_REPLACEMENT_DICT = {
 
 SMART_QUOTE_REPLACE_RE = re.compile("|".join(SMART_QUOTE_REPLACEMENT_DICT.keys()))
 
+SPOILER_CONTENT_RE = re.compile(
+    r"(?s)(?<!\\)(?P<OPEN>\|{2})(?P<SPOILERED>.*?)(?<!\\)(?P<CLOSE>\|{2})"
+)
+
 
 # convenience wrappers
 def filter_urls(to_filter: str) -> str:
@@ -133,3 +139,37 @@ def normalize_smartquotes(to_normalize: str) -> str:
         return SMART_QUOTE_REPLACEMENT_DICT.get(obj.group(0), "")
 
     return SMART_QUOTE_REPLACE_RE.sub(replacement_for, to_normalize)
+
+
+def escape_spoilers(content: str) -> str:
+    """
+    Get a string with spoiler syntax escaped.
+
+    Parameters
+    ----------
+    content : str
+        The string to escape.
+
+    Returns
+    -------
+    str
+        The escaped string.
+    """
+    return SPOILER_CONTENT_RE.sub(r"\\\g<OPEN>\g<SPOILERED>\\\g<CLOSE>", content)
+
+
+def escape_spoilers_and_mass_mentions(content: str) -> str:
+    """
+    Get a string with spoiler syntax and mass mentions escaped
+
+    Parameters
+    ----------
+    content : str
+        The string to escape.
+
+    Returns
+    -------
+    str
+        The escaped string.
+    """
+    return escape_spoilers(filter_mass_mentions(content))