[cloud_firestore]: setState Causes snapshot.data.docChanges to Reinitialize Without Actual Firestore Changes. about flutterfire HOT 5 OPEN

Hello @abineshPalanisamy Thank you for sharing an issue. I see that _buildListView is being called in build. and it has some logic to add to the list employeeData so it can result in duplicate data.

Can you refactor this and test atain?

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Hi @TarekkMA

When setState is called, snapshot.data.docChanges gets reinitialized and behaves as if it is the initial loading by providing all the documents in the Firestore collection with the type DocumentChangeType.added. This can cause duplicate values to be built. On initial loading of the application, snapshot.data.docChanges correctly provides documents with DocumentChangeType.added, which is expected and fine. However, upon calling setState, it again provides all documents in the Firestore collection as snapshot.data.docChanges with DocumentChangeType.added, even if there have been no changes or modifications in Firestore.

We performed logic in the _buildListView method based on snapshot.data.docChanges. Therefore, I concluded that snapshot.data.docChanges behaves improperly when setState is called in the application. This improper functioning leads to duplicate values.

Regards,
Abinesh P

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Calling add in build method will lead to duplicate values, Can you construct the list employeeData only once and try again?

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Hey @abineshPalanisamy. We need more information to resolve this issue but there hasn't been an update in 7 weekdays. I'm marking the issue as stale and if there are no new updates in the next 7 days I will close it automatically.

If you have more information that will help us get to the bottom of this, just add a comment!

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Hi @TarekkMA ,

I believe that the add method is not the cause of the duplicate values. Based on snapshot.data.docChanges, we have added the data from Firestore to the ListView.Builder. Therefore, an improper function of snapshot.data.docChanges leads to the duplicate values.

According to the previous response, when setState is called, snapshot.data.docChanges gets reinitialized and behaves as if it is the initial loading by providing all the documents in the Firestore collection with the type DocumentChangeType.added. This is the root cause of the issue. My concern is why snapshot.data.docChanges gets reinitialized and behaves as if it is the initial loading when setState is called in the application. snapshot.data.docChanges should maintain its state even when we rebuild the app by calling setState.

Regards,
Abinesh P

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