[bgentry]

SQLite metadata updates currently use JSON Merge Patch, which recursively merges nested objects and deletes keys set to JSON null. River's intended behavior is to preserve unrelated top-level keys and replace each supplied value completely, as Postgres's metadata || updates does. This difference can leave a stale resumable cursor on SQLite and cause a completed step to run again on a later retry.

All resumable cursors live inside the same top-level key, river:resumable_cursor. Each cell below shows the full metadata object: Postgres replaces that outer key's entire value, while the existing SQLite merge retains nested entries or interprets null as deletion.

Stored metadata	Metadata updates	Postgres result	SQLite result before this fix
{"river:resumable_cursor":{"c":1}}	{"river:resumable_cursor":{"d":7}}	{"river:resumable_cursor":{"d":7}}	{"river:resumable_cursor":{"c":1,"d":7}}
{"river:resumable_cursor":{"c":1}}	{"river:resumable_cursor":{"d":null}}	{"river:resumable_cursor":{"d":null}}	{"river:resumable_cursor":{"c":1}}
{"river:resumable_cursor":{"c":1}}	{"river:resumable_cursor":null}	{"river:resumable_cursor":null}	{}

For example, c saves a cursor and fails on attempt 1. On attempt 2, c completes, so the worker removes its cursor from the map; then d saves a cursor and fails. The update replaces the cursor map with {"d":7}. A recursive merge retains the old c entry, making c look partly done on attempt 3 and causing it to run again.

Go uses one shared metadata_merge.sql expression to apply each supplied top-level value with jsonb_set. The update list is materialized once, avoiding expression-depth limits and repeated work on Turso. The three generated queries insert this fixed expression through the existing template mechanism because sqlc cannot resolve its CTEs. Fixed SQL and parameter names keep the template replacer's cache enabled.

Java, JavaScript, Rust, and Ruby use fixed SQLite queries that rebuild metadata from retained keys and replacement values. Values are read with -> to preserve JSON types and numeric precision.

The change covers Go, Java, JavaScript, Rust, and Java's conformance helper. Ruby already replaces top-level values; its SQLite merge now also handles large updates without nesting one setter per key. Java's transactional checkpoint fallback keeps its precedence over stored metadata, with attempt updates taking precedence over both. Go keeps malformed stored metadata intact and uses top-level JSON paths without reconstructing existing key names.

Regression coverage includes completed cursor steps, running and stale completions, large updates, literal key names, empty objects, nulls, booleans, and numeric precision. Changelog entries cover every affected language. A separate commit records the cross-language parity expectations in AGENTS.md.

[brandur]

Ah wow, okay that seems like a bad one. Nice find!