Скачать или смотреть Resolving the Expected Singleton Error in Odoo 13 When Switching to Tree View

Learn how to fix the common `Expected singleton` error in Odoo 13 that arises during view transitions, particularly when working with computed fields.
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Fixing the Expected Singleton Error in Odoo 13 When Switching to Tree View

If you’re working with Odoo 13 and encounter the frustrating Expected singleton error while trying to switch from the calendar view to the tree view, you’re not alone. This error occurs when a field is expected to return a single record but instead returns multiple records. Understanding and rectifying this issue is crucial for ensuring your application runs smoothly.

In this guide, we'll explore the cause of the error and the straightforward steps to resolve it.

Understanding the Problem

The error arises primarily during the transition from calendar to tree view. In your specific scenario, you’re utilizing a computed field named requested_hours, which calculates the number of leave hours based on the begin_date and end_date fields. However, if the computation does not correctly handle multiple records, an error like ValueError: Expected singleton: project.leaveoff(51, 52) will emerge, indicating that the code attempted to operate on multiple records where only one was needed.

Key Points Leading to the Issue

The compute method is not adequately set up to handle multiple records.

The code tries to access self.begin_date instead of record.begin_date, which leads to confusion when multiple records are processed.

The Solution

To solve the Expected singleton error, we need to adjust the compute function so it correctly handles the context of individual records. Here’s how to do that:

Step 1: Modify the Compute Method

Open your model and locate the _compute_requested_hours method. You need to ensure that you are referencing the current record properly. Here’s a corrected version of your method:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Key Changes Explained

Initialization of requested_hours: By first setting record.requested_hours to 0.0 for each record, we ensure that any condition not met will not return an erroneous value.

Record Reference: Always reference fields using record.field_name instead of self.field_name. This ensures that you are accessing the fields of the current record rather than the entire set of records, which eliminates the singleton error.

Conclusion

By making these simple but effective modifications to your compute method, you can eliminate the Expected singleton error when switching views in Odoo 13. Understanding the context of your code—especially when dealing with ORM and computed fields—is crucial for building reliable applications.

Should you run into further issues or need additional help with Odoo, feel free to reach out or explore more on Odoo’s documentation. Happy coding!