thread: add a reference to the owner post

app/models/program.py

@@ -16,7 +16,8 @@ class Program(Post):
     # TODO: Compatible calculator models
 
     thread_id = db.Column(db.Integer,db.ForeignKey('thread.id'),nullable=False)
-    thread    = db.relationship('Thread', foreign_keys=thread_id)
+    thread    = db.relationship('Thread', foreign_keys=thread_id,
+                back_populates='owner_program')
 
     # TODO: Number of views, statistics, attached files, etc
 

app/models/thread.py

@@ -12,6 +12,11 @@ class Thread(db.Model):
     top_comment_id = db.Column(db.Integer, db.ForeignKey('comment.id'))
     top_comment    = db.relationship('Comment', foreign_keys=top_comment_id)
 
+    # Post owning the thread, set only by Topic, Program, etc. In general, you
+    # should use [owner_post] which groups them together.
+    owner_topic   = db.relationship('Topic')
+    owner_program = db.relationship('Program')
+
     # Other fields populated automatically through relations:
     #  <comments>   The list of comments (of type Comment)
 
@@ -39,5 +44,13 @@ class Thread(db.Model):
 
         self.top_comment = top_comment
 
+    @property
+    def owner_post(self):
+        if self.owner_topic != []:
+            return self.owner_topic[0]
+        if self.owner_program != []:
+            return self.owner_program[0]
+        return None
+
     def __repr__(self):
         return f'<Thread: #{self.id}>'

app/models/topic.py

@@ -26,7 +26,8 @@ class Topic(Post):
 
     # Associated thread
     thread_id = db.Column(db.Integer,db.ForeignKey('thread.id'),nullable=False)
-    thread    = db.relationship('Thread', foreign_keys=thread_id)
+    thread    = db.relationship('Thread', foreign_keys=thread_id,
+                back_populates='owner_topic')
 
     # Number of views in the forum
     views = db.Column(db.Integer)