Trainhop Adv Target

New Tab Train-hop Targeting

Run the whole recurring train-hop targeting task end-to-end. The only required input is the trainhop version string; everything else is derived.

Input

• Version string, format major.minor.YYYYMMDD.buildid, e.g. 153.4.20260610.40323. If not given, ask for it.
• Fx major for the "includes users of" line — defaults to 151; override only if told.

Steps

1. Ask for the version

If the user didn't supply the trainhop version, ask for it. That is the only input needed.

2. Derive values

From major.minor.YYYYMMDD.buildid:

• Python var: FX_<major>_<minor>_TRAINHOP (drop _<minor> only if minor is 0/first of that major — check what's already in constants.py)
• name: New Tab Fx<major> <Mon>-<DD> Trainhop (month abbrev from YYYYMMDD, e.g. Jun-10)
• slug: newtab-<major>-<MMDD>-trainhop (e.g. newtab-153-0610-trainhop)
• targeting: newtabAddonVersion|versionCompare('<version>') >= 0

3. File the GitHub issue

gh issue create --repo mozilla/experimenter \
  --title "[Targeting] newtab trainhop <version> targeting request" \
  --body "$(cat <<'EOF'
### What is the criteria you need to target based on?

This is to add advanced targeting such that experiments and rollouts can target New Tabs of version \`<version>\` and greater.

This will be very similar to previous targeting requests:

- https://github.com/mozilla/experimenter/issues/15414
- https://github.com/mozilla/experimenter/issues/14888
- https://github.com/mozilla/experimenter/issues/14577
- https://github.com/mozilla/experimenter/issues/14203

### Should the targeting include or exclude users?

Include users of the soon-to-be-released New Tab train-hop for Firefox <fx-major> users on the release channel.

### Additional Notes (optional)

*No response*
EOF
)"

The Jira sync footer is auto-added — leave it out. gh issue create prints the new issue URL; capture the issue number from it for the next steps.

4. Create the branch

git checkout -b <issue-number>-train-hop-<version>

e.g. 15938-train-hop-153.4.20260610.40323.

5. Add the target

Append the new config immediately after the most recent FX_..._TRAINHOP entry in experimenter/experimenter/targeting/constants.py, copying its exact shape:

FX_153_4_TRAINHOP = NimbusTargetingConfig(
    name="New Tab Fx153 Jun-10 Trainhop",
    slug="newtab-153-0610-trainhop",
    description=(
        "Desktop users having the New Tab 153.4.20260610.40323 train hop, "
        "which includes users of Fx151"
    ),
    targeting="newtabAddonVersion|versionCompare('153.4.20260610.40323') >= 0",
    desktop_telemetry="",
    sticky_required=False,
    is_first_run_required=False,
    application_choice_names=(Application.DESKTOP.name,),
)

Confirm the latest entry first: grep -n "TRAINHOP = NimbusTargetingConfig" experimenter/experimenter/targeting/constants.py | tail. This is the only source file that changes.

6. Run ruff

From the experimenter/ directory. Pull the ruff version the repo pins rather than hardcoding it:

RUFF_SPEC=$(grep -m1 '^ruff = ' experimenter/pyproject.toml | sed -E 's/.*"\^?([0-9.]+)".*/\1/')
pipx run --spec "ruff==$RUFF_SPEC" ruff check experimenter/targeting/constants.py
pipx run --spec "ruff==$RUFF_SPEC" ruff format --check --diff experimenter/targeting/constants.py

7. Stage changes and draft the commit message

git add experimenter/experimenter/targeting/constants.py

Print this message — do NOT commit unless asked:

feat(nimbus): Add advanced targeting for newtab trainhop <version>
This commit adds new targeting for the <version> trainhop, which includes users of Fx<fx-major> on the release channel.

Fixes mozilla#<issue-number>

Reference examples

PRs #15676, #15786, #15842 — each is a single ~14-line addition to constants.py.