migration: some fixes here and there

- 0_base.sql: make it rerunnable by dropping hardcoded constraints

manage/cmd/migration/command.py

@@ -101,11 +101,13 @@ async def _ensure_changelog(app, ctx):
         # NOTE: this is a migration breakage,
         # only applying to databases that had their first migration
         # before 4 april 2019 (more on BREAK)
+
+        # if migration_log is empty, just assume this is new
         first = await app.db.fetchval("""
         SELECT apply_ts FROM migration_log
         ORDER BY apply_ts ASC
         LIMIT 1
-        """)
+        """) or BREAK
         if first < BREAK:
             log.info('deleting migration_log due to migration structure change')
             await app.db.execute("DROP TABLE migration_log")
@@ -170,7 +172,7 @@ async def _check_base(app) -> bool:
             await app.db.execute(f"""
             SELECT * FROM {table} LIMIT 0
             """)
-    except asyncpg.DuplicateTableError:
+    except asyncpg.UndefinedTableError:
         return False
 
     return True
@@ -204,7 +206,7 @@ async def migrate_cmd(app, _args):
     if has_base:
         await _insert_log(app, 0, 'migration setup (from existing)')
     else:
-        await apply_migration(app, 0)
+        await apply_migration(app, ctx.scripts[0])
 
     # after that check the current local_change
     # and the latest migration to be run

manage/cmd/migration/scripts/0_base.sql

@@ -27,18 +27,8 @@ CREATE TABLE IF NOT EXISTS user_conn_apps (
     name text NOT NULL
 );
 
-INSERT INTO user_conn_apps (id, name) VALUES (0, 'Twitch');
-INSERT INTO user_conn_apps (id, name) VALUES (1, 'Youtube');
-INSERT INTO user_conn_apps (id, name) VALUES (2, 'Steam');
-INSERT INTO user_conn_apps (id, name) VALUES (3, 'Reddit');
-INSERT INTO user_conn_apps (id, name) VALUES (4, 'Facebook');
-INSERT INTO user_conn_apps (id, name) VALUES (5, 'Twitter');
-INSERT INTO user_conn_apps (id, name) VALUES (6, 'Spotify');
-INSERT INTO user_conn_apps (id, name) VALUES (7, 'XBOX');
-INSERT INTO user_conn_apps (id, name) VALUES (8, 'Battle.net');
-INSERT INTO user_conn_apps (id, name) VALUES (9, 'Skype');
-INSERT INTO user_conn_apps (id, name) VALUES (10, 'League of Legends');
-
+-- there was a chain of INSERTs here with hardcoded names and stuff.
+-- removed it because we aren't in the best business of hardcoding.
 
 CREATE TABLE IF NOT EXISTS instance_invites (
     code text PRIMARY KEY,
@@ -607,6 +597,7 @@ CREATE TABLE IF NOT EXISTS channel_overwrites (
 -- columns in private keys can't have NULL values,
 -- so instead we use a custom constraint with UNIQUE
 
+ALTER TABLE channel_overwrites DROP CONSTRAINT IF EXISTS channel_overwrites_uniq;
 ALTER TABLE channel_overwrites ADD CONSTRAINT channel_overwrites_uniq
     UNIQUE (channel_id, target_role, target_user);
 
@@ -688,6 +679,8 @@ CREATE TABLE IF NOT EXISTS message_reactions (
     emoji_text text
 );
 
+-- unique constraint over multiple columns instead of a primary key
+ALTER TABLE message_reactions DROP CONSTRAINT IF EXISTS message_reactions_main_uniq;
 ALTER TABLE message_reactions ADD CONSTRAINT message_reactions_main_uniq
     UNIQUE (message_id, user_id, emoji_id, emoji_text);