Update CI Image Agent Skill

Updating the CI test image

The redislabs/client-libs-test image is referenced in six places (five live config + one doc). Miss one and either local make test and CI diverge, or a single CI job uses the wrong image. Always edit all relevant locations in one change.

The six locations

| # | File | What lives here |

|---|------|-----------------|

| 1 | Makefile | CLIENT_LIBS_TEST_IMAGE ?= redislabs/client-libs-test:<tag> — default for local make test / make docker.start. |

| 2 | docker-compose.yml | x-default-image: &default-image ${CLIENT_LIBS_TEST_IMAGE:-redislabs/client-libs-test:<tag>} — fallback when the env var is unset. Should match the Makefile default. |

| 3 | .github/workflows/build.yml | redis_version_mapping bash assoc array (["8.X.x"]="<tag>"). Drives the benchmark job and the test-redis-ce matrix via run-tests. |

| 4 | .github/actions/run-tests/action.yml | Identical redis_version_mapping array — the composite action that the matrix jobs invoke. Keep in lockstep with build.yml. |

| 5 | .github/workflows/doctests.yaml | Hardcoded image: redislabs/client-libs-test:<tag> on the redis-stack service — doctests do not consult the mapping. |

| 6 | CONTRIBUTING.md | Prose line "By default the docker image … is redislabs/client-libs-test:<tag>." Documentation only — no CI impact, but goes stale silently. Update it to match the Makefile default. |

Tasks

Update the tag for an existing Redis version (e.g. bump 8.8 → a new release)

• Makefile — replace the tag after redislabs/client-libs-test: on the CLIENT_LIBS_TEST_IMAGE line.
• docker-compose.yml — replace the tag in the :-redislabs/client-libs-test:<tag> default.
• .github/workflows/build.yml — update the ["8.X.x"]="<tag>" line in redis_version_mapping.
• .github/actions/run-tests/action.yml — update the matching ["8.X.x"]="<tag>" line.
• .github/workflows/doctests.yaml — update the image: line only if doctests should run against this version. Doctests typically pin to the latest stable; check before changing.
• CONTRIBUTING.md — update the "By default the docker image … is redislabs/client-libs-test:<tag>." prose line to match the new Makefile default. This one is easy to forget because nothing breaks when it's stale.

If the version that doctests run against (Makefile default) and the mapping for that same minor version diverge, you have a bug — they should resolve to the same tag.

Add a new Redis version to the CI matrix

• .github/workflows/build.yml:
• Add - "<X.Y>.x" to both redis-version matrices (the benchmark job and the test-redis-ce job — they have separate lists).
• Add ["<X.Y>.x"]="<tag>" to redis_version_mapping.
• .github/actions/run-tests/action.yml — add the same ["<X.Y>.x"]="<tag>" entry to its redis_version_mapping.
• If this becomes the new default for local dev, also update Makefile (REDIS_VERSION ?= and CLIENT_LIBS_TEST_IMAGE ?=) and docker-compose.yml.

Remove a Redis version

• .github/workflows/build.yml — drop the - "<X.Y>.x" line from both redis-version matrices and the ["<X.Y>.x"]="..." entry.
• .github/actions/run-tests/action.yml — drop the same ["<X.Y>.x"]="..." mapping entry.
• If Makefile / docker-compose.yml / doctests.yaml were pinned to this version, pick a replacement (usually the next-newest version still in the matrix) and update them too, along with the CONTRIBUTING.md prose line.

Switch to a custom build (e.g. custom-26172898734-debian for an unreleased server feature)

Same as "update the tag," but think about scope:

• Custom tags usually correspond to a single Redis minor — only touch the mapping entry for that minor, not all five rows.
• Custom tags often shouldn't be the local default if they're transient. Confirm with the user before touching Makefile / docker-compose.yml.
• Leave REDIS_VERSION (the numeric 8.8 / 8.6 etc.) alone — it drives SkipBeforeRedisVersion gating in main_test.go, not the image. The custom image still reports its base version.

Verification

After editing, search for any stale tag references:

# Use the Grep tool, not bash grep.
# Pattern: literal old tag, e.g. "8.8-rc1" or "client-libs-test:8.8"

Expected matches: zero in Makefile, docker-compose.yml, .github/**, and CONTRIBUTING.md. A reference in AGENTS.md or the testing skill documentation (e.g. "e.g. redislabs/client-libs-test:8.8-m03") is illustrative — leave it unless the doc is misleading after the change.

Gotchas

• Two mappings, not one. build.yml and run-tests/action.yml each declare their own redis_version_mapping. They are not deduped. Always edit both.
• Two matrices in build.yml. The benchmark job and the test-redis-ce job each have their own redis-version list. Adding/removing a version means editing both.
• doctests.yaml is hardcoded. It doesn't read the mapping. If the team intends "doctests follow the latest stable," verify the tag matches Makefile's default after any change.
• Don't change REDIS_VERSION when only swapping the image. The number gates version-specific test skips (SkipBeforeRedisVersion(8.8, ...)). A custom image built off 8.8 should keep REDIS_VERSION=8.8.
• Env var vs. default. Local users can override with CLIENT_LIBS_TEST_IMAGE=...; docker-compose.yml uses that env var first and falls back to its baked-in default. So the docker-compose default only matters when the Makefile isn't driving things — but it's still load-bearing for direct docker compose up calls. Keep it in sync.