Excluded gift subscriptions from paid subscription charts

[mike182uk]

ref https://linear.app/ghost/issue/BER-3615
ref #27624
ref #27703

• the "Paid subscriptions" bar chart and "Paid subscription breakdown" pie chart were counting gift redemptions as signups and gift end-of-life events as cancellations, which mixed gift activity into charts that are meant to track paid Stripe activity only
• gifts now flow through their own member status (gift) and surface in the Paid members KPI tooltip instead, so duplicating them in the per- cadence/per-tier breakdowns double-counted activity and made the bar and pie charts disagree
• reverted the gift-aware additions to subscription-stats-service so /stats/subscriptions returns paid Stripe deltas and counts only; gift→paid upgrades still appear via the regular paid subscription event flow once the trial converts and MRR begins

[coderabbitai]

Walkthrough

This PR removes gift-handling functionality from the subscription statistics service. The SubscriptionStatsService.getSubscriptionHistory() method now derives subscription delta entries solely from fetchAllSubscriptionDeltas(), eliminating separate paid and gift delta fetching and aggregation paths. The fetchSubscriptionCounts() method is simplified to query only paid subscriptions from members_stripe_customers_subscriptions without gift augmentation. The aggregateCounts() helper is no longer used. Corresponding test changes remove the gifts table from the test schema and delete a unit test case that verified gift signups folding into cadence buckets.

Possibly related PRs

• TryGhost/Ghost#27703: Modifies gift-handling logic in subscription-stats-service and related unit tests for counting redeemed or consumed gifts.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: excluding gift subscriptions from paid subscription charts, which aligns with the primary objective of removing gift activity from charts meant for paid Stripe activity only.
Description check	✅ Passed	The description is directly related to the changeset, providing context about why gift subscriptions are being excluded, referencing related issues and PRs, and explaining the impact on charts and member status flows.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch BER-3615-analytics-remove-gift-subs-from-charts

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@ghost/core/core/server/services/stats/subscription-stats-service.js`:
- Around line 15-16: The reverse-walk seeded from paid-only totals (seeded by
fetchSubscriptionCounts() and iterating subscription deltas from
fetchAllSubscriptionDeltas()) fails to decrement paid counts for same-plan
gift/trial → paid "updated" events with mrr_delta > 0, so the pre-conversion
period still shows the user as paid; update the delta handling to detect
same-plan conversion events (in the code that iterates/normalizes deltas
returned by fetchAllSubscriptionDeltas() / where you apply those deltas
backwards) and treat an "updated" event with mrr_delta > 0 that represents a
conversion from gift/trial to paid as a -1 paid subscriber when walking back
before the conversion timestamp (i.e., subtract one from paid count during
rewind), add logic to distinguish true MRR adjustments from conversion-promoting
updates, and add a regression test that simulates a same-plan gift/trial → paid
conversion to assert pre-conversion paid totals decrement correctly.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 7a3f33fb-65ba-42be-9cdc-71f010fada6a

📥 Commits

Reviewing files that changed from the base of the PR and between 29f8ab3 and 14abcd1.

📒 Files selected for processing (3)

• apps/stats/test/unit/components/growth/new-subscribers-cadence.test.tsx
• ghost/core/core/server/services/stats/subscription-stats-service.js
• ghost/core/test/unit/server/services/stats/subscriptions.test.js

💤 Files with no reviewable changes (2)

• apps/stats/test/unit/components/growth/new-subscribers-cadence.test.tsx
• ghost/core/test/unit/server/services/stats/subscriptions.test.js