From 54a7805a90db814b3ac11bc60ac3b82de5ee747a Mon Sep 17 00:00:00 2001
From: Typosaurus <typosaurus@retoor.molodetz.nl>
Date: Thu, 23 Jul 2026 01:31:16 +0000
Subject: [PATCH] ticket #85 attempt 1

---
 devplacepy/database/schema.py            | 21 +++++++++++++
 devplacepy/services/messaging/persist.py | 40 ++++++++++++++++++------
 2 files changed, 52 insertions(+), 9 deletions(-)

diff --git a/devplacepy/database/schema.py b/devplacepy/database/schema.py
index b9b043b5..289c928f 100644
--- a/devplacepy/database/schema.py
+++ b/devplacepy/database/schema.py
@@ -30,6 +30,26 @@ def migrate_bug_tables_to_issue_tables() -> None:
         logger.info("Dropped table %s after migration", source_name)
 
 
+def _add_message_unique_index() -> None:
+    if "messages" not in db.tables:
+        return
+    with db:
+        db.query(
+            """
+            DELETE FROM messages WHERE id NOT IN (
+                SELECT MIN(id) FROM messages GROUP BY sender_uid, receiver_uid, content
+            )
+            """
+        )
+    _index(
+        db,
+        "messages",
+        "idx_messages_unique_sender_receiver_content",
+        ["sender_uid", "receiver_uid", "content"],
+        unique=True,
+    )
+
+
 def init_db():
     tables = db.tables
     _index(db, "users", "idx_users_username", ["username"])
@@ -131,6 +151,7 @@ def init_db():
         "idx_messages_conversation_rev",
         ["receiver_uid", "sender_uid"],
     )
+    _add_message_unique_index()
     _index(db, "notifications", "idx_notifications_user", ["user_uid"])
     _index(db, "notifications", "idx_notifications_user_read", ["user_uid", "read"])
     _index(db, "push_registration", "idx_push_registration_user", ["user_uid"])
diff --git a/devplacepy/services/messaging/persist.py b/devplacepy/services/messaging/persist.py
index 1d8726a4..ecbcb828 100644
--- a/devplacepy/services/messaging/persist.py
+++ b/devplacepy/services/messaging/persist.py
@@ -18,6 +18,8 @@ from devplacepy.utils import (
     track_action,
 )
 from devplacepy.services.audit import record as audit
+from sqlalchemy.exc import IntegrityError
+
 from devplacepy.services.correction import schedule_correction
 from devplacepy.services.ai_modifier import schedule_modification
 
@@ -110,16 +112,36 @@ def persist_message(
     messages_table = get_table("messages")
     msg_uid = generate_uid()
     created_at = datetime.now(timezone.utc).isoformat()
-    messages_table.insert(
-        {
-            "uid": msg_uid,
-            "sender_uid": sender_uid,
-            "receiver_uid": receiver_uid,
-            "content": content,
-            "read": False,
-            "created_at": created_at,
+
+    try:
+        messages_table.insert(
+            {
+                "uid": msg_uid,
+                "sender_uid": sender_uid,
+                "receiver_uid": receiver_uid,
+                "content": content,
+                "read": False,
+                "created_at": created_at,
+            }
+        )
+    except IntegrityError:
+        existing = messages_table.find_one(
+            sender_uid=sender_uid, receiver_uid=receiver_uid, content=content
+        )
+        if not existing:
+            raise
+        logger.debug(
+            "Dedup via unique constraint for message (uid %s)", existing["uid"]
+        )
+        _content_cache[content_hash] = (time.time(), existing["uid"])
+        return {
+            "uid": existing["uid"],
+            "sender_uid": existing["sender_uid"],
+            "receiver_uid": existing["receiver_uid"],
+            "content": existing["content"],
+            "read": existing.get("read", False),
+            "created_at": existing["created_at"],
         }
-    )
 
     link_attachments(attachment_uids, "message", msg_uid)
     schedule_correction(sender, "messages", msg_uid, request)