SDKMAN environment variables don't change when su-ing to another user

[reitzig]

Run the following commands:

$ whoami
raphael
$ echo $SDKMAN_CANDIDATES_DIR
/home/raphael/.sdkman/candidates
$ su dhtp
Password: 
$ whoami 
dhtp
$ echo $SDKMAN_CANDIDATES_DIR

Expected: /home/dhtp/.sdkman/candidates

Actual: /home/raphael/.sdkman/candidates

[reitzig]

In conf.d/sdk.fish, we re-initialize SDKMAN if not set -q SDKMAN_DIR. This is not enough here: the variable is set (inherited from the shell where su was called), provided the user making that call has SDKMAN installed. If there is sufficient access, sdk will even work.

[reitzig]

Since an automated test seems to be more involved to set up, efficacy of the fix was confirmed by manual testing.

Only: turns out that sdkman-init.sh has the same issue, it won't overwrite existing but wrong values of the environment variables.

[reitzig]

I created a PR upstream: sdkman/sdkman-cli/pull/718