null pointer with symbolic links

[d-a-v]

Bug Report

Current behavior

$ ls -al x y z w

lrwxrwxrwx   1 user user    1 Sep 22 17:25 y -> x      <- y is a symbolic link to x

w:
-rw-r--r--   1 user user    35 Sep 24 00:48 w.ino

x:
-rw-r--r--   1 user user    35 Sep 24 00:48 y.ino

z:
drwxr-xr-x   2 user user  4096 Sep 24 00:41 z.ino      <- z.ino is a directory

$ cat y/y.ino
void setup () { }
void loop () { }

$ cat w/w.ino
void setup () { }
void loop () { }

$ arduino-cli  compile --fqbn arduino:avr:nano y
(segfaults)

$ arduino-cli  compile --fqbn arduino:avr:nano z
(segfaults)

$ arduino-cli  compile --fqbn arduino:avr:nano w
(works)

Symbolic link as sketch directory fails with a segmentation fault.
Directory instead of a file fails with a segmentation faults (dup #358)

Expected behavior

Symbolic link as sketch directory should work.
Directory instead of a file may fail with an error message.

Environment

• CLI version (output of arduino-cli version): arduino-cli Version: 0.0.0-git Commit:
git describe --tag: 0.3.7-alpha.preview-143-gafdf609
• OS and platform: Linux avr

Additional context

none