AutoMod: improved handling for media data

There were several issues occuring related to rules that require data
from the media embed (which is added on to Link objects asynchronously
by the media scraper). Items are re-checked by AutoMod when the scraper
adds an item, but some rules that required that data were still being
checked and executed anyway before it had actually completed, so were
not behaving correctly.

This change makes the checks to see if the rule needs the data from
the media object more robust, which should ensure that these rules are
never processed until the item comes into the queue again when the
scraper attaches the embed data.

r2/r2/lib/automoderator.py

@@ -100,6 +100,7 @@ def replace_placeholders(string, data, matches):
             "{{kind}}": "comment",
             "{{title}}": data["link"].title,
         })
+        media_item = data["link"]
     elif isinstance(item, Link):
         replacements.update({
             "{{kind}}": "submission",
@@ -107,16 +108,17 @@ def replace_placeholders(string, data, matches):
             "{{title}}": item.title,
             "{{url}}": item.url,
         })
+        media_item = item
 
-        if item.media_object:
-            oembed = item.media_object.get("oembed")
-            if oembed:
-                replacements.update({
-                    "{{media_author}}": oembed.get("author_name", ""),
-                    "{{media_title}}": oembed.get("title", ""),
-                    "{{media_description}}": oembed.get("description", ""),
-                    "{{media_author_url}}": oembed.get("author_url", ""),
-                })
+    if media_item.media_object:
+        oembed = media_item.media_object.get("oembed")
+        if oembed:
+            replacements.update({
+                "{{media_author}}": oembed.get("author_name", ""),
+                "{{media_title}}": oembed.get("title", ""),
+                "{{media_description}}": oembed.get("description", ""),
+                "{{media_author_url}}": oembed.get("author_url", ""),
+            })
 
     for placeholder, replacement in replacements.iteritems():
         string = string.replace(placeholder, replacement)
@@ -689,22 +691,23 @@ class RuleTarget(object):
 
         return match_patterns
 
-    def item_has_necessary_data(self, item):
-        """Check whether the item has all data required by the conditions."""
+    @property
+    def needs_media_data(self):
+        """Whether the component requires data from the media embed."""
         if any(field.startswith("media_") for field in self.match_fields):
-            if not item.media_object:
-                return False
+            return True
 
-        if self.reports and not item.reported:
-            return False
+        # check if any of the fields that support placeholders have media ones
+        potential_placeholders = [self.report_reason]
+        if self.set_flair:
+            potential_placeholders.extend(self.set_flair.values())
+        if any(text and "{{media_" in text for text in potential_placeholders):
+            return True
 
-        return True
+        return False
 
     def check_item(self, item, data):
         """Return whether an item satisfies all of the defined conditions."""
-        if not self.item_has_necessary_data(item):
-            return False
-
         if not self.check_nonpattern_conditions(item, data):
             return False
 
@@ -1177,6 +1180,19 @@ class Rule(object):
 
         return False
 
+    @property
+    def needs_media_data(self):
+        """Whether the rule requires data from the media embed."""
+        for attr in ("comment", "modmail", "message"):
+            text = getattr(self, attr, None)
+            if text and "{{media_" in text:
+                return True
+
+        if any(comp.needs_media_data for comp in self.targets.values()):
+            return True
+
+        return False
+
     @property
     def matches(self):
         return self.targets["base"].matches
@@ -1248,6 +1264,11 @@ class Rule(object):
                     ban_info.get("unbanner") != ACCOUNT.name):
                 return False
 
+        if self.needs_media_data:
+            if isinstance(item, Link) and not item.media_object:
+                return False
+            elif isinstance(item, Comment) and not data["link"].media_object:
+                return False
 
         return True