[iacsha]

Scope table-existence checks to the connection catalog (fixes #489)

Problem

The engine's "does this table exist?" checks call DatabaseMetaData.getTables(null, null, …)
with a null catalog. On MySQL, Connector/J then searches every database the login can
see, not just the one in the URL. When one login has rights on more than one OIE database
on the same server, the engine finds another database's tables and skips creating or
repairing its own:

• First startup fails. ServerMigrator.initDatabase → DatabaseUtil.tableExists(conn, "CONFIGURATION") finds the other database's CONFIGURATION, skips mysql-database.sql,
  and getCurrentVersion then fails on the missing SCHEMA_INFO.
• Per-channel message tables aren't recreated. JdbcDao.checkAndCreateChannelTables
  lists tables across all visible databases, so a missing D_MC<n> looks present when
  another database has a table of that name; messages then fail with Table 'oie_b.D_MC1' doesn't exist.

Fix

Pass connection.getCatalog() as the catalog argument at the three sinks:

• DatabaseUtil.tableExists (both the upper- and lower-case lookups)
• JdbcDao.checkAndCreateChannelTables
• JdbcDao.tableExists

Each engine then only sees tables in its own database. This is portable:

• MySQL — getCatalog() returns the current database, so the lookup is scoped correctly.
• Derby / Oracle — getCatalog() returns null, so behaviour is unchanged (same as today).
• PostgreSQL / SQL Server — getCatalog() returns the current database, which is the
  only catalog on that connection, so the result is unchanged.

Equivalent to the reporter's ?nullDatabaseMeansCurrent=true MySQL URL workaround, but
applied in code and database-agnostic.

Tests

Added DatabaseUtilTest.tableExists_scopesLookupToConnectionCatalog: mocks the connection
and verifies getTables is called with the connection's own catalog ("oie_b"), never
null.

./gradlew :server:test --tests "*DatabaseUtilTest*" → 1 test, 0 failures.

Notes

The deeper message-table path (checkAndCreateChannelTables) is fixed the same way but is
not covered by a new unit test here, as it needs a live JdbcDao/connection; the shared
root cause and fix are identical across all three sinks.

[github-actions]

Test Results

  142 files  +1    142 suites  +1   3m 25s ⏱️ +5s
  920 tests +1    920 ✅ +1  0 💤 ±0  0 ❌ ±0 
1 052 runs  +1  1 046 ✅ +1  6 💤 ±0  0 ❌ ±0 

Results for commit dc2c0a6. ± Comparison against base commit 0638c21.

[mgaffigan]

Please add missing DCO.

Also: if this is a mysql specific thing, it should live in the MySQL DAO - not in JdbcDao.

[iacsha]

Thanks @mgaffigan, good call. Moved it so only MySQL changes behaviour (DCO is fixed too). There isn't a MySQL-specific DAO class today, so I followed the existing setQuoteChar pattern in MysqlDaoFactory:

• JdbcDao gets a setScopeTablesToCatalog(boolean) flag, off by default. With it off, both table lookups pass a null catalog exactly as main does, so Derby, Postgres, SQL Server and Oracle are unchanged.
• MysqlDaoFactory.getDao() turns it on, next to setQuoteChar('')`.
• DatabaseUtil.tableExists is a static helper with no DAO behind it, so it scopes to connection.getCatalog() only when the driver reports MySQL or MariaDB as the product name, and keeps the null catalog otherwise.

Tests: JdbcDaoTest checks the default lookup still uses a null catalog and that the flag scopes it to the connection's catalog. DatabaseUtilTest checks MySQL scopes and PostgreSQL keeps null. I also switched that test's header to Open Integration Engine Contributors to match #562.