Is there a tool out there that finds and merges pdfs based on hashes so as to eliminate duplicates? Has there been any discussion on creating such a tool?
You could use some external tool on the 'storage' directory in your Zotero data directory to find duplicates, paste the parent directory's 8-character name into the Zotero search bar in All Fields & Tags mode, and delete one of the two PDFs that way.
We'd take a patch to automatically remove one of two identical PDFs when merging duplicates (and to scan existing sibling attachments), but it would have to somehow deal with any other metadata that might exist on the attachment item (different titles, different filenames, tags, attachment notes).
Along with the above complications, many PDFs are watermarked, which is why this has never been a higher priority.
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We'd take a patch to automatically remove one of two identical PDFs when merging duplicates (and to scan existing sibling attachments), but it would have to somehow deal with any other metadata that might exist on the attachment item (different titles, different filenames, tags, attachment notes).
Along with the above complications, many PDFs are watermarked, which is why this has never been a higher priority.