Fix NPE for media-only Document in QdrantVectorStore (GH-3609)

[devMtn30]

Problem

Storing a Document that contains only media currently results in a NPE because
ValueFactory.value(null) is invoked.

Solution

• Check document.isText().
• If false, throw an IllegalArgumentException with a clear message.

Issue

Closes #3609

[dev-jonghoonpark]

if (!document.isText()) {
    throw new IllegalArgumentException("""
            QdrantVectorStore supports only text-based Document for now –
            received media-only Document; see issue #3609.
            """);
}

var payload = QdrantValueFactory.toValueMap(document.getMetadata());
payload.put(CONTENT_FIELD_NAME, io.qdrant.client.ValueFactory.value(document.getText()));
return payload;

How about this code?

It can prevent unnecessary execution of QdrantValueFactory.toValueMap.
And it's more intuitive.

[devMtn30]

if (!document.isText()) {
    throw new IllegalArgumentException("""
            QdrantVectorStore supports only text-based Document for now –
            received media-only Document; see issue #3609.
            """);
}

var payload = QdrantValueFactory.toValueMap(document.getMetadata());
payload.put(CONTENT_FIELD_NAME, io.qdrant.client.ValueFactory.value(document.getText()));
return payload;

How about this code?

It can prevent unnecessary execution of QdrantValueFactory.toValueMap. And it's more intuitive.

Thanks for the suggestion-updated!

[dev-jonghoonpark]

I was wondering if there’s a specific reason for declaring a separate variable named documentContent.
If you believe it’s necessary, feel free to keep it. However, in my opinion, it might not be needed.

Additionally, it might be better to move it either before or after the declaration of payload (line 307).

[devMtn30]

Removed the extra variable, inlined document.getText(), and force pushed. Thanks for the spot!

[ilayaperumalg]

@devMtn30 Thank you for the PR. I have submitted a PR which addresses this issue across the vector stores: #3687. Could you review the PR please?

[ilayaperumalg]

Closing this PR in favour of #3687