Safety, --force, and --dry-run

Workler's mutating commands are conservative by default: nothing that exists is ever overwritten, and every command that changes something can print its plan first.

Nothing is overwritten by default

add and apply never replace an existing destination. Two states count as already done and are reported ok:

• a symlink that already points at the right source (already linked)
• a copy whose destination content matches the source (destination matches source)

Anything else — a symlink pointing somewhere else, a regular file, a directory — is a conflict. The error shows both sides and what is currently in the way:

cannot link node_modules: destination already exists
  source:      /path/to/project/node_modules
  destination: /path/to/project/.worktrees/feature-a/node_modules (existing directory)
re-run with --force to replace the destination

Conflicts are detected by content, not timestamps — a copied .env you have since edited in the workspace is a conflict, not silently "up to date".

--dry-run

Prints exactly what would be copied, linked, skipped, replaced, or conflicted — without changing anything:

$ workler apply feature-a --dry-run
dry run: nothing will be changed
ok     link node_modules (already linked)
would  copy .env -> .worktrees/feature-a/.env
conflict copy config/local.json
1 conflict(s); re-run with --force to replace the destination(s)

For add, no clone is created; the whole plan — clone, branch, rules — is printed instead:

$ workler add feature-b --dry-run
cloning /path/to/project
     to /path/to/project/.worktrees/feature-b
create branch feature-b from HEAD
would  link node_modules -> .worktrees/feature-b/node_modules
would  copy .env -> .worktrees/feature-b/.env

--force

Replaces conflicting destinations, and says what it replaced:

copied .env (replaced existing file)

--force also appears on workler remove, where it means something different: remove the workspace even though it has uncommitted changes.

The same caution everywhere else

The safety-first stance runs through the whole CLI:

• workler remove refuses to delete a workspace with any local changes — untracked files included, since deletion is permanent.
• workler sync only ever fast-forwards; dirty workspaces and diverged branches are skipped, never merged or rebased.
• workler branch-sync never moves a checked-out branch or one with local-only commits.
• Untracked files created by copy rules never count as "dirty" for status and sync. Only remove treats them as blocking — it is the one command that would delete them.