Restic: Restic Mount - Be More Vocal Regarding Permission Issues

Output of restic version

restic 0.8.3
compiled with go1.10.1 on linux/amd64

How did you run restic exactly?

sudo mkdir /mnt/restic-b2
--------
:: [stephen@waddleduck] ~
$ ls -ls /mnt
total 12
4 drwxr-xr-x  2 root root 4096 Apr 17 22:13 restic-b2
----------
export B2_ACCOUNT_KEY=XXXXX
export B2_ACCOUNT_ID=YYYYYYY
export RESTIC_PASSWORD=ZZZZZZZz
cd ~/
restic -r b2:bucket-name:/ mount /mnt/restic-b2
------------------
password is correct
*hit CTRL+C at this point after waiting about 7 minutes*
  signal interrupt received, cleaning up
context canceled, ignoring
fusermount: exit status 1
also, the following messages were logged by a library:
2018/04/17 22:18:21 mount helper error: fusermount: user has no write access to mountpoint /mnt/restic-b2
unable to umount (maybe already umounted?): exit status 1: fusermount: entry for /mnt/restic-b2 not found in /etc/mtab
-----------------------
:: [stephen@waddleduck] ~
$ sudo chown stephen:stephen /mnt/restic-b2
-------------
[sudo] password for stephen:
:: [stephen@waddleduck] ~
$ restic -r b2:bucket-name:/ mount /mnt/restic-b2
------------
password is correct
Now serving the repository at /mnt/restic-b2
Don't forget to umount after quitting!

What backend/server/service did you use to store the repository?

Backblaze B2

Expected behavior

Restic should warn you on the command line that the repository couldn't be mounted due to permissions issues.

Actual behavior

Restic does not inform you of this until you "cancel" after waiting for a confirmation of mounting (which is not received). Then, the user is informed as a "mount helper error".

Steps to reproduce the behavior

Make a new directory which your user account does not have write access to, and try mounting to it. Then, after waiting some time (to confirm it won't mount), Ctrl+c, and you will see what happens.

Do you have any idea what may have caused this?

Presumably just that nobody thought it would be necessary to generate such a message at this point :)

Do you have an idea how to solve the issue?

Catch the error and display relevant info to the user.

Did restic help you or made you happy in any way?

Absolutely; every day :D Restic is life!