DOC-6827 Prepare Lettuce probabilistic data type docs

[andy-stark-redis]

DOC-6827 — Lettuce probabilistic data type docs

Adds Lettuce (Java) coverage for the probabilistic data types, in two parts.

Examples

Staged Lettuce async + reactive doctests (local_examples/<set>/lettuce-async|lettuce-reactive/) for:

Set	Data-type page
bf_tutorial	Bloom filter
cuckoo_tutorial	Cuckoo filter
cms_tutorial	Count-min sketch
topk_tutorial	Top-K
tdigest_tutorial	t-digest
hll_tutorial	HyperLogLog
home_prob_dts	combined rundown / landing

The per-type data-type pages embed clients-example without a lang_filter, so the new Java-Async / Java-Reactive tabs appear automatically once the example pipeline regenerates examples.json — no edits to those pages needed.

Rundown page

New content/develop/clients/lettuce/prob.md, adapted from the Jedis page, with lang_filter="Java-Async,Java-Reactive".

⚠️ Preemptive work — reads against unreleased API

Probabilistic command support is not in a released lettuce-core yet. Examples are written against the Lettuce feature PRs:

• Merged to redis/lettuce main: BF (MOD-17269 Document Agent Memory sensitive-data exclusions #3760), CF (#3774), Top-K (#3780)
• Still open (fork Dgramada/lettuce): CMS (#3821), t-digest (#3823) — signatures may still change

A Codex review flagged every non-HLL call as an unknown method; that's expected against the pinned released jar, not a defect. When the features release: re-pin lettuce-core, re-run the doctest harness (the REMOVE-block asserts become real oracles then), and re-diff the CMS/t-digest signatures. CMS/t-digest are the higher-risk pair to re-verify.

⚠️ Forward risk — Lettuce 8.x reactive-accessor removal (pickup trigger)

All seven lettuce-reactive examples obtain their commands via connection.reactive() (returning RedisReactiveCommands). Somewhere in the Lettuce 8.x "reactor-optional" work, the reactive() accessor is removed — reactive commands move to connection.commands(RedisReactiveCommands.factory()). Related 8.x churn already merged: EventBus rework #3789 / Flux-surface removal #3790.

Pickup trigger: if the release that ships the probabilistic methods also removes reactive(), every reactive example must be migrated from connection.reactive() to connection.commands(RedisReactiveCommands.factory()) before merge (and prob.md's prose at the top of the reactive section updated to match).

⚠️ This trigger is currently UNPINNED — re-pin it before relying on it

Corrected 2026-08-06 (/pr-scan-review). This section previously named Lettuce
#3842 as the PR that removes reactive(). That is no longer true of
#3842's diff. Verified against the live PR on 2026-08-06:

• #3842 is titled "[reactor-optional] Credentials as adapter 8x", targets feature/reactor-optional-1, is still
  open, and last moved 2026-07-14.
• Its diff is 21 files, all credentials/connect-path (CredentialsProvider, AsyncCredentialsProviderAdapter,
  RedisHandshake, ConnectionState, RedisURI, RedisClient, RedisClusterClient, the authx classes, and tests).
  There is no StatefulRedisConnection/StatefulRedisClusterConnection impl in the diff, and no accessor removal.
• The Bugbot summary inside #3842's own body does describe removing eager reactive() fields and methods — but it
  reviewed commit 404f10f9 and is stale against the current diff. Do not treat that summary as the pin.

So the risk described above is still believed real (the reactor-optional umbrella is broad, and #3842 may simply have
been narrowed with the accessor removal split out elsewhere), but this PR no longer pins the PR that carries it.

On /unpark, before anything else: locate the PR or commit that actually removes the reactive() accessor —
search redis/lettuce for changes to StatefulRedisConnection/StatefulRedisConnectionImpl and for
commands(RedisReactiveCommands.factory()) — and record it here with its state, base branch and head SHA. If no such
change exists on a branch heading for a release, downgrade this from a pickup trigger to a watch item and say so.

🤖 Generated with Claude Code

---

Note

Medium Risk
Documentation-only, but examples depend on probabilistic APIs not yet in released lettuce-core (especially CMS and t-digest), so CI or readers on the current jar may fail until dependencies and signatures are updated.

Overview
Adds Lettuce client documentation for Redis probabilistic data types: a new content/develop/clients/lettuce/prob.md overview (mirroring other client prob pages) with embedded clients-example snippets filtered to Java-Async and Java-Reactive.

Introduces doctest-style Java examples under local_examples/ for Bloom filter, Cuckoo filter, Count-min sketch, Top-K, t-digest, HyperLogLog, plus a combined home_prob_dts set—each in async and reactive variants using STEP_START/STEP_END markers for doc extraction.

Examples call probabilistic commands on RedisAsyncCommands / RedisReactiveCommands (e.g. bfReserve, cmsInitByProb, tdigestCreate, topKReserve) so Java-Async / Java-Reactive tabs can appear on existing data-type pages after examples.json regeneration, without editing those pages in this PR.

^{Reviewed by Cursor Bugbot for commit 48553bc. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

DOC-6827

[github-actions]

Staging links:
https://redis.io/docs/staging/DOC-6827-prepare-lettuce-probabilistic-data-type-docs/develop/clients/lettuce/prob/