fix(tutor): open a temporary copy instead of original file #38522

Problem:
`:Tutor` should open a copy of the tutor file instead of the original. This is
because edits modify the original file buffer, and crashes or other misuse could
potentially corrupt the original file even if it's WO.

Solution:
Copy the tutor file to a temp path before opening. Store the original path in
`b:tutor_file` so metadata json loading still works.

- `tutor#TutorCmd` will now copy the tutor file to a temp path via `tempname()`
  before opening with `drop`. Store the original path in `b:tutor_file` only
  after the buffer is created.
- `tutor#LoadMetadata` now uses `b:tutor_file` to resolve the JSON path instead
  of `expand('%')`, which now points to the temp copy buffer
- `ftplugin/tutor.vim` does not make the `tutor#LoadMetadata` call anymore. It
  was guarded by `filereadable(expand('%').'.json')` which fails for the new
  temp copy path logic . Instead, `tutor#LoadMetadata` is already called
  directly inside `tutor#TutorCmd` since we are already assumed to enable
  interactive.

Co-authored-by: Phạm Bình An <111893501+brianhuster@users.noreply.github.com>

0 files changed, 0 insertions, 0 deletions