datastore: fix WithIgnoreFieldMismatch for nested slices

[bhshkh]

Fixes: #10822

This change ensures that propertyLoader.load continues iterating through slice elements even if individual elements encounter loading errors (like ErrFieldMismatch).

Previously, when loading a slice of structs, if one element caused an error (e.g. valid field mismatch), the loader would abort immediately. This prevented subsequent elements from being loaded, even if the user intended to ignore these mismatches using WithIgnoreFieldMismatch.

The fix captures the first error encountered but continues the loop to ensure all valid data is loaded. The error is returned at the end, preserving the existing error reporting behavior (which WithIgnoreFieldMismatch relies on).

[gemini-code-assist]

Summary of Changes

Hello @bhshkh, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refines the data loading mechanism for slices within the datastore, ensuring that the WithIgnoreFieldMismatch option behaves correctly. By modifying the error handling logic, the system now processes all slice elements, capturing only the initial error, which allows for more robust and complete data loading when partial failures are expected or ignored.

Highlights

• Error Handling in Slice Loading: The load function in datastore/load.go has been modified to continue processing all elements of a slice even if an error occurs during the loading of an individual element. Previously, the function would abort immediately upon the first error.
• Preserving First Error: While iterating through slice elements, the first error encountered is now captured and stored. The function will return this first error only after attempting to load all elements in the slice.
• Fix for WithIgnoreFieldMismatch: This change specifically addresses an issue where the WithIgnoreFieldMismatch option was not functioning as intended for nested slices, as the loader would stop prematurely on the first field mismatch error.

Changelog

• datastore/load.go
  • Modified the load method to iterate through all slice elements, even if loadOneElement returns an error for a specific element.
  • Introduced a firstErr variable to store the initial error encountered during slice iteration, returning it only after the loop completes.

Activity

• The pull request was created by bhshkh to address issue datastore: WithIgnoreFieldMismatch option works for just first record in embedded / nested struct array case. #10822, as indicated in the PR description.

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[gemini-code-assist]

Code Review

This pull request addresses a bug where loading data into a slice of structs would prematurely terminate upon encountering an error, such as a field mismatch, even when WithIgnoreFieldMismatch was specified. The change modifies the property loader to continue iterating through all slice elements, capturing the first error but ensuring all valid data is loaded. This aligns with the expected behavior of WithIgnoreFieldMismatch. The fix is well-targeted and correctly implemented. I have no further suggestions.

[shollyman]

This looks odd to me because you're propagating strings rather than errors, but it adheres to the loadOneElement contract.