The Problem with Timezone Conversion

Oct 13, 2025 by wbrum.org 107 views

Understanding the Issue

Switching timezones can cause incorrect double charges due to the way the next payment date is stored and interpreted. This issue arises when the site timezone is changed, and the next payment date is not adjusted accordingly. As a result, two recurring charges may happen on the same day, and the next payment date may be 6 hours ahead.

Reproduction Steps

To reproduce this issue, follow these steps:

Step 1: Set Up the Site

With the site timezone in UTC, purchase a monthly recurring access plan with a 1 day trial.
Switch the site to UTC-6 timezone

Step 2: Wait for the Renewal

Wait a couple of days for the renewal to happen

Expected Behavior

One recurring charge should happen for the monthly access plan, and the next payment date should be at the same time (timezone adjusted).

Actual Behavior

However, two recurring charges happen on the same day, and the next payment date is 6 hours ahead. The first charge happens as the original time due to the task already being scheduled.

Tech Notes

The next payment date is stored in the current local timezone. It's then interpreted as the new timezone when read on renewal. This can cause issues when the timezone is changed, as the next payment date is not adjusted accordingly.

The Problem with Timezone Conversion

When the site timezone is changed, the next payment date is set to the same time, but in the new time zone. However, this can result in the next payment date appearing to be in the future. This is because the first (original) payment happened at the time in the old timezone.

The Check for Daylight Savings Time

There's a check that the next payment isn't within 2 hours in case of daylight savings time. However, this check doesn't account for a totally different timezone that's more than 2 hour difference.

The Impact on Scheduled Tasks

The next recurring payment scheduled task in the new time zone is also affected by this issue. The task is not adjusted to the new timezone, resulting in incorrect scheduling.

Conclusion

Switching timezones can cause incorrect double charges due to the way the next payment date is stored and interpreted. This issue arises when the site timezone is changed, and the next payment date is not adjusted accordingly. To resolve this issue, the next payment date should be stored and interpreted in the same timezone as the site. Additionally, the scheduled tasks should be adjusted to the new timezone to ensure correct scheduling.

Recommendations

To avoid this issue, follow these recommendations:

Store the next payment date in the same timezone as the site.
Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Future Development

To resolve this issue, the following changes should be made:

Update the code to store the next payment date in the same timezone as the site.
Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Timeline

The following is a proposed timeline for resolving this issue:

Week 1: Update the code to store the next payment date in the same timezone as the site.
Week 2: Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Week 3: Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Conclusion

Q: What is the issue with switching timezones?

A: The issue arises when the site timezone is changed, and the next payment date is not adjusted accordingly. This can result in two recurring charges happening on the same day, and the next payment date being 6 hours ahead.

Q: Why is the next payment date not adjusted when the site timezone is changed?

A: The next payment date is stored in the current local timezone. When the site timezone is changed, the next payment date is not adjusted to the new timezone. This can cause issues when the timezone is changed, as the next payment date is not adjusted accordingly.

Q: What is the impact on scheduled tasks when the site timezone is changed?

A: The next recurring payment scheduled task in the new time zone is also affected by this issue. The task is not adjusted to the new timezone, resulting in incorrect scheduling.

Q: How can I avoid this issue?

A: To avoid this issue, follow these recommendations:

Store the next payment date in the same timezone as the site.
Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Q: What changes need to be made to resolve this issue?

A: The following changes should be made to resolve this issue:

Update the code to store the next payment date in the same timezone as the site.
Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Q: What is the proposed timeline for resolving this issue?

A: The following is a proposed timeline for resolving this issue:

Week 1: Update the code to store the next payment date in the same timezone as the site.
Week 2: Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Week 3: Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Q: What are the benefits of resolving this issue?

A: Resolving this issue will ensure that the site operates correctly even when the timezone is changed. This will prevent incorrect double charges and ensure that the next payment date is adjusted accordingly.

Q: Who should be involved in resolving this issue?

A: The following individuals should be involved in resolving this issue:

Development team: responsible for updating the code to store the next payment date in the same timezone as the site.
Operations team: responsible for adjusting the scheduled tasks to the new timezone when the site timezone is changed.
Quality assurance team: responsible for testing the changes to ensure that the issue is resolved.

Q: What are the next steps in resolving this issue?

A: The next steps in resolving this issue are:

Update the code to store the next payment date in the same timezone as the site.
Adjust the scheduled tasks to the new timezone when the site timezone is changed.
Implement a check to ensure that the next payment date is not within 2 hours of the current time in case of daylight savings time.

Q: What is the expected outcome of resolving this issue?

A: The expected outcome of resolving this issue is that the site will operate correctly even when the timezone is changed. This will prevent incorrect double charges and ensure that the next payment date is adjusted accordingly.