An .xlsx picture below the last text row and past row 10 is uploaded but never indexed #45181

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Dify version

main (dca4024e57)

Cloud or Self Hosted

Self Hosted (Source)

Steps to reproduce

Upload an .xlsx to a knowledge base where a picture sits in a table column below the last row that has text, past row 10. For example, a sheet whose last text row is 2, with a picture anchored at C12 under an Image header:

     A          B          C
1    Question   Answer     Image
2    Q1         A1
...
12                         [picture]

api/core/rag/extractor/excel_extractor.py uploads embedded images first (_extract_images_from_sheet), then walks rows with:

for row in sheet.iter_rows(min_row=start_row, max_col=max_col_idx, values_only=False):

Without max_row, openpyxl stops at sheet.max_row. A row that holds only a picture has no cells, so it is never visited. Rows up to 10 survive only by accident: the header scan (_find_header_and_columns) calls iter_rows(max_row=10), which makes openpyxl create empty cells for rows 1 to 10 and raises max_row to 10.

✔️ Expected Behavior

Each picture-only row becomes a document with its markdown image, as it does for rows up to 10:

"Question":"Q1";"Answer":"A1";"Image":""
"Question":"";"Answer":"";"Image":"![image](.../files/<upload id>/file-preview)"

❌ Actual Behavior

Only the first line is indexed. The picture is still saved to storage with an UploadFile row, but no document references it, so it cannot be retrieved.

Found while testing #44849. A fix with a real-workbook test follows.