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🐛 Fixed non-deterministic member attribution resolution #28491

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Merged
9larsons merged 1 commit into from
Jun 10, 2026
Merged

🐛 Fixed non-deterministic member attribution resolution #28491

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14 changes: 12 additions & 2 deletions ghost/core/core/server/services/member-attribution/member-attribution-service.js
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Original file line number Diff line number Diff line change
Expand Up @@ -142,7 +142,12 @@ class MemberAttributionService {
* @returns {Promise<import('./attribution-builder').AttributionResource|null>}
*/
async getMemberCreatedAttribution(memberId) {
const memberCreatedEvent = await this.models.MemberCreatedEvent.findOne({member_id: memberId}, {require: false, withRelated: []});
// A member can have more than one created event row (member_id is not unique),
// so order deterministically to avoid non-deterministic attribution resolution.
const memberCreatedEvent = await this.models.MemberCreatedEvent
.where('member_id', memberId)
.query(qb => qb.orderBy('created_at', 'desc').orderBy('id', 'desc'))
.fetch({require: false, withRelated: []});
if (!memberCreatedEvent) {
return null;
}
Expand All @@ -163,7 +168,12 @@ class MemberAttributionService {
* @returns {Promise<import('./attribution-builder').AttributionResource|null>}
*/
async getSubscriptionCreatedAttribution(subscriptionId) {
const subscriptionCreatedEvent = await this.models.SubscriptionCreatedEvent.findOne({subscription_id: subscriptionId}, {require: false, withRelated: []});
// A subscription can have more than one created event row (subscription_id is not unique),
// so order deterministically to avoid non-deterministic attribution resolution.
const subscriptionCreatedEvent = await this.models.SubscriptionCreatedEvent
.where('subscription_id', subscriptionId)
.query(qb => qb.orderBy('created_at', 'desc').orderBy('id', 'desc'))
.fetch({require: false, withRelated: []});
if (!subscriptionCreatedEvent) {
return null;
}
Expand Down
75 changes: 39 additions & 36 deletions ghost/core/test/unit/server/services/member-attribution/service.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,17 @@ const assert = require('node:assert/strict');

const MemberAttributionService = require('../../../../../core/server/services/member-attribution/member-attribution-service');

// Mocks a Bookshelf model that is queried via `.where(...).query(...).fetch(...)`,
// resolving the fetch to the given event (or null).
function createEventModelMock(event) {
const chainable = {
where: () => chainable,
query: () => chainable,
fetch: async () => event
};
return chainable;
}

describe('MemberAttributionService', function () {
describe('Constructor', function () {
it('doesn\'t throw', function () {
Expand Down Expand Up @@ -268,9 +279,7 @@ describe('MemberAttributionService', function () {
it('returns null when no event exists', async function () {
const service = new MemberAttributionService({
models: {
MemberCreatedEvent: {
findOne: () => null
}
MemberCreatedEvent: createEventModelMock(null)
}
});

Expand All @@ -281,21 +290,19 @@ describe('MemberAttributionService', function () {
it('returns attribution from event', async function () {
const service = new MemberAttributionService({
models: {
MemberCreatedEvent: {
findOne: () => ({
get: function (key) {
const values = {
attribution_id: 'attr_123',
attribution_url: '/test',
attribution_type: 'post',
referrer_source: 'source',
referrer_medium: 'medium',
referrer_url: 'https://referrer.com'
};
return values[key];
}
})
}
MemberCreatedEvent: createEventModelMock({
get: function (key) {
const values = {
attribution_id: 'attr_123',
attribution_url: '/test',
attribution_type: 'post',
referrer_source: 'source',
referrer_medium: 'medium',
referrer_url: 'https://referrer.com'
};
return values[key];
}
})
},
attributionBuilder: {
build: function (attribution) {
Expand Down Expand Up @@ -326,9 +333,7 @@ describe('MemberAttributionService', function () {
it('returns null when no event exists', async function () {
const service = new MemberAttributionService({
models: {
SubscriptionCreatedEvent: {
findOne: () => null
}
SubscriptionCreatedEvent: createEventModelMock(null)
}
});

Expand All @@ -339,21 +344,19 @@ describe('MemberAttributionService', function () {
it('returns attribution from event', async function () {
const service = new MemberAttributionService({
models: {
SubscriptionCreatedEvent: {
findOne: () => ({
get: function (key) {
const values = {
attribution_id: 'attr_123',
attribution_url: '/test',
attribution_type: 'post',
referrer_source: 'source',
referrer_medium: 'medium',
referrer_url: 'https://referrer.com'
};
return values[key];
}
})
}
SubscriptionCreatedEvent: createEventModelMock({
get: function (key) {
const values = {
attribution_id: 'attr_123',
attribution_url: '/test',
attribution_type: 'post',
referrer_source: 'source',
referrer_medium: 'medium',
referrer_url: 'https://referrer.com'
};
return values[key];
}
})
},
attributionBuilder: {
build: function (attribution) {
Expand Down
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