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DocumentIterator usage can corrupt data if you forget to zero/nil your buffer

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
65/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Domain
databases

Research direction

Look at the DocumentIterator implementation in the documentdb package, likely in a file like iterator.go. Examine how the slice reference is reused across iterations. The fix involves ensuring the buffer is cleared or a new slice is allocated each iteration. Test by running the example code with and without the fix to verify data corruption is prevented.

Written by the indexing model from the issue text.

Description

Since it is a slice reference, any nested structs or arrays in your data will be sparsely overwritten during iteration and can still include old data from past iteration if you follow the docs:

	// ...
	var docs []Document

	iterator := documentdb.NewIterator(
		client, documentdb.NewDocumentIterator("coll_self_link", nil, &docs, documentdb.PartitionKey("1"), documentdb.Limit(1)),
	)

	for iterator.Next() {
		if err := iterator.Error(); err != nil {
			log.Fatal(err)
		}
		fmt.Println(len(docs))
	}    

	// ...
}```

Instead, nil the buffer like this:

func main() {
// ...
var docs []Document

iterator := documentdb.NewIterator(
	client, documentdb.NewDocumentIterator("coll_self_link", nil, &docs, documentdb.PartitionKey("1"), documentdb.Limit(1)),
)

for iterator.Next() {
	if err := iterator.Error(); err != nil {
		log.Fatal(err)
	}
	fmt.Println(len(docs))
            docs = nil // zero your buffer to avoid corrupt data!
}    

// ...

}```

Dominant language
Go
Stars
31
Forks
26
No merged PRs in 30d

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