siblings.py (make siblings): a FILE, or a directory it cannot list, at ../<Project> ends in a traceback (NotADirectoryError or PermissionError at siblings.py:558), exit 1, where the doctor calls the slot NOT A CLONE #735

Goal: make siblings answers for every slot beside the holder, without a traceback. It calls a FILE, or a directory it cannot list, at ../<Project> NOT A CLONE and leaves it exactly as it is, as #705 makes the doctor say.

Filed by lane openRepoShape-3 under v1.1.1, on Brett Heap's word of 2026-10-16T13:35:28Z ("yes create v1.1.1"). #705's writer found it, and lane 3's reviewer RV-d measured it while reviewing #705 (#669, #673), as S1 and M1. It is not a regression: main's siblings.py does the same.

What happens. RV-d ran the holder's own scripts/siblings.py --dry-run from its family folder:

• A FILE at ../IRRS: any(target.iterdir()) at siblings.py:558 raises NotADirectoryError, a traceback, exit 1.
• A directory with mode 0311 at ../IRRS (enterable, not listable; 711 is common for another user's directory): the same line raises PermissionError, a traceback, exit 1.
• A directory with mode 000: the same.
• With shape-doctor.py: the members row says, member by member, what make siblings does with the directory beside the holder, in its own word and in place's order, so it no longer says it places a member it leaves exactly as it is, and it spells every value it quotes, so an ESC or a CR in a url no longer reaches the terminal (#669, #673) #705, the doctor's members row calls the first two slots not-a-clone. shape-doctor.py: the members row says, member by member, what make siblings does with the directory beside the holder, in its own word and in place's order, so it no longer says it places a member it leaves exactly as it is, and it spells every value it quotes, so an ESC or a CR in a url no longer reaches the terminal (#669, #673) #705's agreement test holds the FILE case as a strict xfail tied to this issue.

What to do:

• In siblings.py's slot reading, treat a slot that is not a directory, or that cannot be listed (OSError), as NOT A CLONE: reported, and never cloned into or moved.
• Turn shape-doctor.py: the members row says, member by member, what make siblings does with the directory beside the holder, in its own word and in place's order, so it no longer says it places a member it leaves exactly as it is, and it spells every value it quotes, so an ESC or a CR in a url no longer reaches the terminal (#669, #673) #705's strict xfail into a pass.
• Add the mode-0311 case, skipped on Windows and as root.
• siblings.py is a pinned family-root copy, so a change costs each holder an upstream-changed row. The PR body says so.
• Coordinate with siblings.py (make siblings): the printed mv goes astray over an existing .holder/.folder or a dangling link, a lone surrogate or NUL in project: is a traceback, a url with NEL or U+2028 is cut, two warnings print paths raw #690, which changes the printed mv in the same file.

Lands after: #705.