Issue Summary

Plugins that implement com.atlassian.confluence.plugins.index.api.Extractor2 that does not index the attachment but returns a non-null value (e.g. empty StringBuilder()) from extractText() method will cause file attachments not to be indexed in search as a side effect.
Following plugins seem to be causing this effect:

• Comala Workflows
• ConfiForms
• LucidChart OnPrem
• Questions for Confluence

Steps to Reproduce

1. Install Questions for Confluence
2. Attach a text file to any page
3. Search a word contained in the text file

Expected Results

Attachment text file is found using search.

Actual Results

Text file is not indexed and not found.

The below messages can be found confluence log if debug logging for com.atlassian.bonnie.search.extractor is enabled when the files are correctly indexed but not when the indexing is skipped:

2020-10-15 15:14:20,630 DEBUG [Caesium-1-2] [bonnie.search.extractor.BaseAttachmentContentExtractor] addFields Starting to index attachment: sample.txt

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available