feat: Value Commands for Lettuce backend

[vchomakov]

Summary

Adds the ValueCommands / ReactiveValueCommands implementation on the Lettuce backend, building on the proxy infrastructure already in place.

This is the first command group to land on Lettuce. The patterns established here — converter registry usage, reactive-to-async bridging via LettuceResult.toUni, blocking-over-reactive timeout wrapping — will be reused by every subsequent command group (Hash, List, Set, SortedSet, …).

What's included

Production code

• AbstractLettuceCommands<K, V> — shared base class for Lettuce-backed reactive command groups. Holds the RedisAsyncCommands<K, V> handle obtained from StatefulRedisConnection#async(). Mirrors the role of AbstractRedisCommands on the Vert.x side.

• LettuceReactiveValueCommandsImpl<K, V> — implements all 27 methods of ReactiveValueCommands<K, V>. Each method validates arguments, looks up any structured argument converter in LettuceConverterRegistry, invokes the matching Lettuce async command, and adapts the resulting CompletionStage<T> to Uni<T>. Registers the Value-Commands converters in a static initializer on first class load.

• LettuceBlockingValueCommandsImpl<K, V> — implements ValueCommands<K, V> by delegating to the reactive impl and awaiting each result with .await().atMost(timeout). Parallels BlockingStringCommandsImpl on the Vert.x side.

• LettuceValueCommandsConverters — translates Quarkus SetArgs / GetExArgs to their Lettuce counterparts. Parses the wire-format token list returned by toArgs() (the Quarkus arg classes expose no getters). Self-registers with LettuceConverterRegistry via an idempotent, thread-safe register().

Tests

• LettuceValueCommandsConvertersTest — 16 pure-JVM unit tests. For each SetArgs / GetExArgs flag combination (EX, EXAT, PX, PXAT, NX, XX, KEEPTTL, GET, PERSIST, combined, empty), builds the Quarkus object, converts it, renders the Lettuce args to wire tokens via CommandArgs#toCommandString(), and asserts they match the original Quarkus toArgs() output. Verifies semantic round-trip without needing a Redis instance.

• LettuceValueCommandsIntegrationTest — 16 tests against a real Redis 7 container via Testcontainers. Exercises both reactive and blocking implementations end-to-end:

  • GET/SET round-trip; SET with NX/XX/EX
  • SETEX / PSETEX / SETNX TTL behavior
  • SETGET (legacy and modern)
  • INCR / DECR / INCRBY / DECRBY / INCRBYFLOAT
  • APPEND / STRLEN
  • MGET (including a missing key mapped to null) / MSET / MSETNX (all-or-nothing semantics)
  • GETEX with EX and PERSIST
  • GETDEL / GETRANGE / SETRANGE
  • Reactive API smoke test
  • getDataSource() accessor pass-through

Each test calls flushdb() in @BeforeEach for isolation.

Notes on LCS / lcsLength

Lettuce 6.5.x exposes only stralgoLcs, which emits the deprecated STRALGO LCS command — removed in Redis 7.0. Rather than shipping a broken code path, both methods fail with a clear UnsupportedOperationException:

LCS is not supported on the Lettuce backend with Lettuce 6.5.x: the only available API emits the deprecated STRALGO command, which was removed in Redis 7.0. Native LCS support will be enabled with the Quarkus 4 / Lettuce 7 upgrade.

When the Lettuce 7 upgrade lands, enabling LCS is a mechanical one-line replacement in each method; the helper constructing this exception gets deleted. Two integration tests lock in the current behavior.

Out of scope

• Wiring into @Inject RedisDataSource / @Inject ReactiveRedisDataSource — backend selection is a separate follow-up PR
• Other command groups (Key, Hash, List, Set, SortedSet, …) — each follows the same template and lands as its own PR
• Transactions, pipelining, pub/sub on Lettuce
• Native-image support

Verification

• extensions/redis-client/runtime full test suite — all tests passing, no regressions
• New tests: 32/32 green (16 unit + 16 integration)

Dependency chain

This branch depends on the proxy infrastructure branch (lettuce-proxy-infrastructure). Once that merges, this rebases cleanly on top.