DatabaseMetaData.getTables: empty types[] matches none instead of all (should equal null) (#1570)

[peco-engineer-bot]

Summary

Automated fix for #1570 — DatabaseMetaData.getTables: empty types[] matches none instead of all (should equal null).

In both listTables implementations (SEA DatabricksMetadataQueryClient and Thrift DatabricksThriftServiceClient) an empty types[] array is now normalized to null, so it carries no type constraint and matches ALL table types per the JDBC DatabaseMetaData.getTables contract (identical to passing null), replacing the prior match-none short-circuit. Verified with the live-warehouse e2e test and the Thrift unit test; spotless:check is clean.

Root cause & plan

Root cause: Both metadata client implementations short-circuit when getTables is passed an empty types[] array, returning an empty result set. In DatabricksMetadataQueryClient.listTables (SEA, lines 145-147) and DatabricksThriftServiceClient.listTables (Thrift, lines 516-518) there is an explicit if (tableTypes != null && tableTypes.length == 0) return <empty result> guard with the comment "empty array = return nothing". This misreads the JDBC DatabaseMetaData.getTables contract: an empty (or null/absent) type list carries no type constraint and must match ALL table types (equivalent to null). The downstream filter in MetadataResultSetBuilder.getTablesResult already handles empty correctly (tableTypes != null && tableTypes.length > 0 → no filtering), so the early-return guards are the sole cause of the match-none behavior.
Files: jdbc-core/src/main/java/com/databricks/jdbc/dbclient/impl/sqlexec/DatabricksMetadataQueryClient.java, jdbc-core/src/main/java/com/databricks/jdbc/dbclient/impl/thrift/DatabricksThriftServiceClient.java, jdbc-core/src/test/java/com/databricks/jdbc/integration/e2e/MetadataTests.java
Planned coverage:

• Live e2e test (integration/e2e/MetadataTests): create a table in the connection's catalog/schema, then call md.getTables(catalog, schema, tableName, new String[]{}) and assert the table IS listed — i.e. empty types[] matches all, identical to passing null. Currently returns 0 rows (red). Exercised through the default warehouse connection (getValidJDBCConnection). (Empty types[] must match all table types (match-all), same as null — the single divergence reported.)

Files changed

• src/test/java/com/databricks/jdbc/integration/e2e/MetadataTests.java
• src/main/java/com/databricks/jdbc/dbclient/impl/sqlexec/DatabricksMetadataQueryClient.java
• src/main/java/com/databricks/jdbc/dbclient/impl/thrift/DatabricksThriftServiceClient.java
• src/test/java/com/databricks/jdbc/dbclient/impl/thrift/DatabricksThriftServiceClientTest.java
• NEXT_CHANGELOG.md

Test plan

• com.databricks.jdbc.integration.e2e.MetadataTests#testGetTablesEmptyTypesMatchesAll — fails (red) against the original code, passes (green) after the fix
• com.databricks.jdbc.dbclient.impl.thrift.DatabricksThriftServiceClientTest#testListTablesWithEmptyTypesMatchesAll — fails (red) against the original code, passes (green) after the fix

NO_CHANGELOG=true

🤖 Generated by engineer-bot (bug-fix flow) — review before merge.

[peco-review-bot]

✅ No issues identified by the review bot.