When `css()`/`xpath()` are called with both `adaptive=True` and
`auto_save=True`, the relocation branch guarded the re-save with
`if elements is not None`. However `relocate()` returns an empty
list (never `None`) when no candidate clears the `percentage`
threshold, so the guard always passed and `self.save(elements[0], ...)`
raised `IndexError: list index out of range`.
This crashes exactly when adaptive resilience is needed most: the page
structure changed enough that nothing matches above the threshold.
Fix: use a truthiness check (`if elements and auto_save`) so the
re-save is skipped when relocation yields nothing. The successful
relocation path (which re-saves the relocated element) is unchanged.
Added a regression test that fails before the fix (IndexError) and
passes after.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Mubashir Rahim
cd4cdc69e6