Accidental file deletion when linking

[MooseV2]

While configuring my dotbot config, I ran into an issue that caught me off guard and led to the accidental deletion of source files.

# Directory structure
dotbot.yml
t_source/
------> /config.json

# Initial dotbot.yml
- defaults:
    link:
      relink: true
      create: true
      force: true

- link:
    t_target: t_source

After running dotbot -c dotbot.yml, I get the following

$ dotbot -c dotbot.yml
Creating link t_target -> /home/user/test/t_source
All links have been set up

==> All tasks executed successfully

$ ls -l
-rw-rw-r-- 1 user user  110 Mar 21 22:48 dotbot.yml
drwxrwxr-x 2 user user 4096 Mar 21 22:47 t_source/
lrwxrwxrwx 1 user user   27 Mar 21 22:50 t_target -> /home/user/test/t_source/

$ ls t_target
config.json

Now, I wanted to change my config to instead link the file directly (config.json) instead of the directory (t_source).

    - link:
-       t_target: t_source
+       t_target/config.json: t_source/config.json

Here is where the issue lies. Remember:

1. t_target is a symlink pointing to t_source
2. t_target/config.json exists since we previously linked it.

So when dotbot goes to link this file, it sees that t_target/config.json exists and deletes it to make room for the new link. Since this points to the real original file, t_source/config.json is deleted!

$ ls t_source/config.json
t_source/config.json

$ dotbot -c dotbot.yml
Removing t_target/config.json
Nonexistent source for t_target/config.json : /home/user/test/t_source/config.json
Some links were not successfully set up

==> Some tasks were not executed successfully

$ ls t_source/config.json
ls: cannot access 't_source/config.json': No such file or directory

This is fundamentally user error, but I think it's worth putting some checks around since not only did it delete my source file, but it wasn't clear why it did it until I took some time to investigate.