dotfiles/.config/dot/.claude/tasks/0008-folders-collision-handling.md

spec, blocked-by

spec	blocked-by
dot-setup-folders	0007-folders-non-empty-confirmation

What to build

Make the --yes-confirmed merge from the prior slice collision-safe: when a legacy folder and its short-named target both contain an entry with the same name, use no-clobber move semantics so the target's existing file is never silently overwritten. Report which files were skipped due to a collision, and leave the legacy folder in place (don't remove it) whenever any collision occurred during that folder's migration, rather than deleting a folder that still holds something that couldn't be merged.

This closes the gap left by the old bash setup_folders's naive mv $from/* $to, which had no collision protection at all.

Acceptance criteria

• A filename collision between a legacy folder and its already-populated short-named target is skipped, not overwritten (the target's existing file is preserved byte-for-byte)
• The skipped collision is reported to the user
• The legacy folder is left in place (not removed) when a collision occurred, even though --yes was given and other non-colliding files in it were moved
• Re-running dot setup folders after a collision was reported and left in place behaves consistently (doesn't lose the previously-skipped file, doesn't re-move already-migrated files)
• ~/.config/dot/tests/dot.fish covers the above cases and fishtape ~/.config/dot/tests/dot.fish passes