Re: V+=1 doesn't work if V is a reference to an integer array element

[Léa Gris]

Le 14/01/2021 à 16:15, Chet Ramey écrivait :
> On 1/13/21 4:40 PM, Léa Gris wrote:
> > Le 13/01/2021 à 22:13, Chet Ramey écrivait :
> > > The `-i' forces arithmetic evaluation, which makes this expand to the 
> > > equivalent of `declare -n b=1'. That's an invalid name for a nameref,
> > > which you'd see if you used `declare -n b=1' instead. The assignment
> > > error causes `declare' to return an non-zero status, but the error
> > > message checks the original value, not the result of arithmetic
> > > evaluation, and the `a[0]' is valid.
> > >
> > > I guess I never thought people would try to use integer variables as
> > > namerefs, since nameref values can't be digits.
> >
> >
> > Sorry Chet, this does not make sense to me. There is no error message.
>
> OK, let's be clear that this sequence of commands from your message is what
> we're talking about:
>
> unset a b
> declare -ai a=(1)
> declare -in b="a[0]"
> declare -p a b
>
> I get this result:
>
> declare -ai a=([0]="1")
> x4: line 4: declare: b: not found
>
> and I explained why there is no variable `b'.


Not the same issue and not exactly same sequence of commands:

unset a; unset -n b
declare -ai a=(1)
declare -n b="a[0]" # No i flag at that point for b
typeset -ni b # Now b also has a int flag alongside the nameref
b+=2 # This is only allowed if b has the int flag
declare -p a b

As Oğuz wrote:
> Seems to be another bug. `bind_variable_internal' calls both
> `assign_array_element' and `make_variable_value' with ASS_APPEND in flags (
> https://git.savannah.gnu.org/cgit/bash.git/tree/variables.c#n3140 ), the
> latter returns 6 (4 + 2), the former adds it to a[0]'s value.


--
Léa Gris