I’ve been using https://github.com/Fuuzetsu/shellcheck-nix-attributes on most of
my derivations, and attaching it to one derived from `mkShell` resulted in
```
shellcheck_buildPhase
In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 1:
echo "------------------------------------------------------------" >>$out
^-- SC2129 (style): Consider using { cmd1; cmd2; } >> file instead of individual redirects.
^--^ SC2086 (info): Double quote to prevent globbing and word splitting.
Did you mean:
echo "------------------------------------------------------------" >>"$out"
In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 2:
echo " WARNING: the existence of this path is not guaranteed." >>$out
^--^ SC2086 (info): Double quote to prevent globbing and word splitting.
Did you mean:
echo " WARNING: the existence of this path is not guaranteed." >>"$out"
In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 3:
echo " It is an internal implementation detail for pkgs.mkShell." >>$out
^--^ SC2086 (info): Double quote to prevent globbing and word splitting.
Did you mean:
echo " It is an internal implementation detail for pkgs.mkShell." >>"$out"
In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 4:
echo "------------------------------------------------------------" >>$out
^--^ SC2086 (info): Double quote to prevent globbing and word splitting.
Did you mean:
echo "------------------------------------------------------------" >>"$out"
In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 5:
echo >> $out
^--^ SC2086 (info): Double quote to prevent globbing and word splitting.
Did you mean:
echo >> "$out"
In /nix/store/8774inwznc87dwhac90winc9b5k6gmkb-nix-shell_shellcheck_buildPhase line 7:
export >> $out
^--^ SC2086 (info): Double quote to prevent globbing and word splitting.
Did you mean:
export >> "$out"
For more information:
https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
https://www.shellcheck.net/wiki/SC2129 -- Consider using { cmd1; cmd2; } >>...
```
——— https://garnix.io/build/qgxbameB
This addresses the shellcheck complaints.
`exit -1` is equivalent to `exit 255`, since Bash does modulo 256 on the
number.
As per ShellCheck:
> SC2242 (error): Can only exit with status 0-255. Other data should be
> written to stdout/stderr.
GNU tar will apparently silently include mtime of files if --mtime is
passed with an unrecognized date format. This led to hash instability
from those mtimes and this fixes it to force all mtimes to epoch
timestamp 0.
