fix: handle empty notification recipients by SahilJat · Pull Request #7589 · Flagsmith/flagsmith

SahilJat · 2026-05-25T05:50:21Z

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Changes

Closes Sendgrid API calls raising HTTP 400 Bad Requests #7353
This PR resolves an issue where the background tasks for sending API usage and flag blocked notifications crash with a BadRequestsError: HTTP Error 400: Bad Request.

This occurs when using external API-based email
backends (like SendGrid or AWS SES) and the
organisation has no valid recipients (e.g., zero
total users, or no admin users when the usage
threshold is <100%). Unlike traditional SMTP
backends, API backends strictly validate the payload and return a 400 error if the recipient_list is empty.
Changes made:
Added an early return guard checking if not recipient_emails: in _send_api_usage_notification.
Added the same early return guard in
send_api_flags_blocked_notification to prevent the same crash there.
Logs a warning (notification.no_recipients)
instead of attempting to send the email.

How did you test this code?

Added a new unit test: test_handle_api_usage_notifications__no_admin_users_ _skips_notification to explicitly verify that the
notification is safely skipped and no 400 error is thrown when an organisation has no users.
Ran existing unit tests for organisations_tasks
to ensure no regressions.

vercel · 2026-05-25T05:50:26Z

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Code Review

This pull request introduces checks to handle cases where no recipient emails are found for API usage and blocked notifications, including a new unit test for this scenario. Feedback suggests that returning early without creating a notification record will lead to redundant processing and log noise in subsequent task runs, as the organization will be re-evaluated every 12 hours.

Zaimwa9 · 2026-05-25T08:54:17Z

@SahilJat thanks for your contribution. You'll need to run make lint or generate-docs to regenerate the events catalogue as you created 2 new ones

SahilJat · 2026-05-25T12:01:23Z

Hi @Zaimwa9 i did run make lint and it shows around 22k lines edited , is this fine?

Zaimwa9 · 2026-05-25T12:36:38Z

Sorry, I should have been more specific as the command should be run from api/, it edited all the docs it seems

SahilJat · 2026-05-26T05:06:05Z

hi @Zaimwa9 thanks for the hint , i did the changes required now, please have a look and let me know.

for more information, see https://pre-commit.ci

Zaimwa9

Tests need an update 👍

codecov · 2026-05-26T08:46:42Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.42%. Comparing base (e85f77b) to head (55f751a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7589      +/-   ##
==========================================
- Coverage   98.57%   98.42%   -0.15%     
==========================================
  Files        1464     1464              
  Lines       56625    56651      +26     
==========================================
- Hits        55818    55760      -58     
- Misses        807      891      +84

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SahilJat · 2026-05-26T09:15:32Z

Hi @Zaimwa9 all the test cases are passing and test coverage is covered too. Thanks

Zaimwa9

Sorry for the back and forth. Gemini comment is worth addressing

vercel · 2026-05-28T08:09:19Z

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…00-error # Conflicts: # api/custom_auth/serializers.py

Zaimwa9

Thanks for the change and sorry for the back and forth around marking the notification as sent.

A couple of comments, the changes in the custom auth serializer don't look like they belong to this PR though.

Zaimwa9 · 2026-06-29T08:32:04Z

    )

    # Then
+    print(response.content)


Suggested change

print(response.content)

Zaimwa9 · 2026-06-29T08:34:03Z

+            "sign_up_type",
        )
        read_only_fields = ("is_active", "uuid", "marketing_consent_given")
-        write_only_fields = ("sign_up_type",)
        extra_kwargs = {
+            "sign_up_type": {"required": False},
            "email": {
                "validators": list[object](),
-            }
+            },
        }


I don't see how this is related to the issue ?

Zaimwa9 · 2026-06-29T08:35:39Z


+    recipient_emails = list(recipient_list.values_list("email", flat=True))
+    if not recipient_emails:
+        logger.warning(


We might want to make it less verbose like

logger.warning( "notification.skipped", organisation__id=organisation.id, reason="no_recipients", notification_type="flags_blocked", )

Zaimwa9 · 2026-06-29T08:36:11Z

+        logger.warning(
+            "notification.no_recipients",
+            organisation__id=organisation.id,
+            matched_threshold=matched_threshold,
+        )


and here we could log this way

logger.warning( "notification.skipped", organisation__id=organisation.id, reason="no_recipients", )

Zaimwa9 · 2026-06-29T08:40:27Z

+        OrganisationAPIUsageNotification.objects.create(
+            organisation=organisation,
+            percent_usage=matched_threshold,
+            notified_at=timezone.now(),
+        )


We shouldn't create a record here. It would wrongly marked it as notified. Meaning it won't be retried especially if a user is added to the mailing list.

If we just log and return, next time the task runs it will try again. Costs a bit of repeated work but as these notifications are critical. It is better to leave it self-heal

I apologize as I trusted Gemini comment to early in the last review. That's on me

fix: handle empty notification recipients

80d9427

SahilJat requested a review from a team as a code owner May 25, 2026 05:50

SahilJat requested review from khvn26 and removed request for a team May 25, 2026 05:50

github-actions Bot added the api Issue related to the REST API label May 25, 2026

gemini-code-assist Bot reviewed May 25, 2026

View reviewed changes

Comment thread api/organisations/task_helpers.py

SahilJat requested a review from a team as a code owner May 25, 2026 06:03

github-actions Bot added the docs Documentation updates label May 25, 2026

SahilJat requested a review from a team as a code owner May 25, 2026 11:42

SahilJat force-pushed the fix/api-usage-email-400-error branch from 2da8be0 to 07d4f78 Compare May 25, 2026 11:56

SahilJat closed this May 25, 2026

SahilJat reopened this May 25, 2026

SahilJat force-pushed the fix/api-usage-email-400-error branch 3 times, most recently from 001cf1e to f44aa4e Compare May 26, 2026 05:03

[pre-commit.ci] auto fixes from pre-commit.com hooks

1add2f6

for more information, see https://pre-commit.ci

SahilJat force-pushed the fix/api-usage-email-400-error branch from f44aa4e to 1add2f6 Compare May 26, 2026 05:08

Update generated documentation

fc2c28a

Zaimwa9 requested changes May 26, 2026

View reviewed changes

Comment thread api/tests/unit/organisations/test_unit_organisations_tasks.py

chore: regenerate API documentation

1fcd6f8

SahilJat force-pushed the fix/api-usage-email-400-error branch from 21991e4 to 1fcd6f8 Compare May 26, 2026 08:40

Zaimwa9 requested changes May 26, 2026

View reviewed changes

test coverage

7c75218

SahilJat force-pushed the fix/api-usage-email-400-error branch from 5a1373e to 7c75218 Compare May 26, 2026 09:39

chore: regenerate events catalogue

c37f096

vercel Bot deployed to Preview – docs May 28, 2026 08:10 View deployment

fix: test assertion for API usage threshold notification

0a1ea10

SahilJat requested a review from Zaimwa9 June 8, 2026 17:05

flagsmith-engineering Bot assigned Zaimwa9 Jun 8, 2026

fix: correct write_only_fields to extra_kwargs for sign_up_type

f33ef16

SahilJat force-pushed the fix/api-usage-email-400-error branch from f00f7b1 to f33ef16 Compare June 18, 2026 04:36

Merge remote-tracking branch 'origin/main' into fix/api-usage-email-4…

55f751a

…00-error # Conflicts: # api/custom_auth/serializers.py

Zaimwa9 requested changes Jun 29, 2026

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SahilJat commented May 25, 2026

Changes

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