object_to_pascal_voc applied the 1-index offset in place (xyxy += 1).
Because Detections.__iter__ yields each row of xyxy as a view sharing
memory with detections.xyxy, detections_to_pascal_voc wrote the +1 shift
straight back into the caller's array. A single export shifted every box
by +1px; a second export compounded it, producing wrong XML. A single
export-then-reload happened to round-trip because from_pascal_voc
subtracts 1, which is why no test caught it.
Rebind to a new array (xyxy = xyxy + 1) instead of mutating in place.
On-disk output is unchanged; the source detections are left intact.
Add regression tests asserting object_to_pascal_voc does not mutate its
inputs and that two consecutive exports are identical and leave xyxy
unchanged.
---------
Co-authored-by: jirka <6035284+Borda@users.noreply.github.com>
Co-authored-by: claude[bot] <209825114+claude[bot]@users.noreply.github.com>
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