There seems to be an issue with the following new bash-5.0 feature:
A nameref name resolution loop in a function now resolves to a variable by
that name in the global scope.
[ Note: "warning: x: circular name reference" messages omitted below. ]
While referencing such a nameref works as described, scalar assignment to it
modifies the variable from the next higher scope rather than the global one:
$ inner() { local -n x=x; x=3; }
$ outer() { local x=2; inner; declare -p x; }
$ x=1; outer; declare -p x
declare -- x="3" # x changed in outer()
declare -- x="1" # global x not changed
There is odd/broken behavior when `declare' is used to modify such a
variable,
similar to https://lists.gnu.org/archive/html/bug-bash/2018-07/msg00072.html
I think the right thing here would be for `declare' to act as if the `-g`
flag
had been supplied and modify the variable in the global scope?
$ f() { local -n x=x; declare x=(2); x=3; declare -p x; }
$ x=1; f; declare -p x
declare -an x=([0]="2") # local nameref borked
declare -- x="1" # global x not changed
$ f() { local -n x=x; declare x=2; }; f
-bash: declare: `2': invalid variable name for name reference
$ f() { local -n x=x; declare -a x=y; declare -p x; }
$ x=1; f; declare -p x
declare -an x=() # local nameref borked
declare -a x=([0]="y") # global x correct (?)
$ unset x; declare -p x
declare -- x="1" # original after unset
`unset' (no `-n') modifies the nameref:
$ f() { local -n x=x; unset x; declare -p x; }
$ x=1; f; declare -p x
declare -- x
declare -- x="1"
If the target is an array reference that results in a circular nameref,
then
neither referencing nor assigning to the nameref works:
$ f() { local -n x=x[0]; echo "<$x>"; x=2; }
$ x=1; f
<>
-bash: `x[0]': not a valid identifier
