Accidental file deletion when linking#360

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 ``` ````yaml # 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`). ```diff - 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.