metrics: Compute trial exclusion from bucket end instead of date_trunc

_not_in_trial / _in_trial truncated both trial_end and the bucket
timestamp and compared those. `trial_end < t + interval` gives the
same answer without the date_trunc calls on either side.

Author: Yopi

server/polar/metrics/metrics.py

@@ -29,21 +29,23 @@
 # trial_end, ended_or_ends_at, subscription_id, customer_id).
 
 
-def _not_in_trial(t: ColumnElement[datetime], i: TimeInterval) -> ColumnElement[bool]:
+def _not_in_trial(
+    t: ColumnElement[datetime], i: TimeInterval
+) -> ColumnElement[bool]:
     buckets = t.table.c
     return or_(
         buckets.trial_end.is_(None),
-        i.sql_date_trunc(cast(SQLColumnExpression[datetime], buckets.trial_end))
-        <= i.sql_date_trunc(t),
+        buckets.trial_end < t + i.sql_interval(),
     )
 
 
-def _in_trial(t: ColumnElement[datetime], i: TimeInterval) -> ColumnElement[bool]:
+def _in_trial(
+    t: ColumnElement[datetime], i: TimeInterval
+) -> ColumnElement[bool]:
     buckets = t.table.c
     return and_(
         buckets.trial_end.is_not(None),
-        i.sql_date_trunc(cast(SQLColumnExpression[datetime], buckets.trial_end))
-        > i.sql_date_trunc(t),
+        buckets.trial_end >= t + i.sql_interval(),
     )
 
 

server/tests/metrics/test_service.py

@@ -3514,6 +3514,54 @@ async def test_trial_excluded_from_mrr(
         assert mar.trial_monthly_recurring_revenue == 0
         assert mar.trial_committed_monthly_recurring_revenue == 0
 
+    async def test_trial_mrr_is_stable_across_now_values(
+        self,
+        metrics_harness: MetricsHarness,
+        metrics_session: AsyncSession,
+    ) -> None:
+        case = QUERY_CASES_BY_LABEL["trial_excluded_from_mrr"]
+        org_ctx = metrics_harness.organizations[case.org_key]
+        auth_subject = _metrics_auth_subject(
+            metrics_harness.user,
+            metrics_harness.unauthorized_user,
+            org_ctx.organization,
+            case.auth_type,
+        )
+
+        async def get_metrics(now: datetime) -> MetricsResponse:
+            return await metrics_service.get_metrics(
+                metrics_session,
+                auth_subject,
+                start_date=case.start_date,
+                end_date=case.end_date,
+                timezone=ZoneInfo(case.timezone),
+                interval=case.interval,
+                organization_id=[org_ctx.organization.id]
+                if case.organization_id_filter or case.auth_type == "user"
+                else None,
+                product_id=[org_ctx.product_ids[k] for k in case.product_keys] or None,
+                billing_type=list(case.billing_types) or None,
+                customer_id=[org_ctx.customer_ids[k] for k in case.customer_keys]
+                or None,
+                metrics=list(case.metrics) if case.metrics is not None else None,
+                now=now,
+            )
+
+        early = await get_metrics(datetime(2024, 2, 1, tzinfo=UTC))
+        later = await get_metrics(datetime(2024, 6, 1, tzinfo=UTC))
+
+        assert len(early.periods) == len(later.periods) == 3
+        for e, l in zip(early.periods, later.periods, strict=True):
+            assert e.timestamp == l.timestamp
+            assert e.monthly_recurring_revenue == l.monthly_recurring_revenue
+            assert (
+                e.trial_monthly_recurring_revenue == l.trial_monthly_recurring_revenue
+            )
+            assert (
+                e.trial_committed_monthly_recurring_revenue
+                == l.trial_committed_monthly_recurring_revenue
+            )
+
     async def test_mrr_subscription_forever_discount(
         self,
         metrics_harness: MetricsHarness,