add spec test for nested subshell parse error

[melvinw]

gzip has a utility script called zdiff. It gets used at some point in the check step when building gzip from source. It also makes use of nested subshells in a few places. The osh parser is tripping over these. Here's an example from a simple script.

((echo foo) | tr o 0)
     ^~~
_tmp/foo.sh:1: Unexpected token after arithmetic expression (Id.Word_Compound != Id.Arith_RParen)

Other shells seem to handle this case, so in preparation for an inbound fix, this commit adds a new spec test to cover it.

Related to #2398

[andychu]

Oh yes I saw this in the logs ... I wonder if this is the same as #2337

Awhile ago I added a couple tests in test/spec.sh divergence

---

I think this one might require some design; there is the issue of

• (( vs ( ( with space
• $(( vs $( ( with space - similar bug I think I may have seen

In theory I think regtest/aports/cause.awk can help us de-dupe these bugs, though probably we don't have a smooth process yet

[melvinw]

Oh great! We can close this then

[andychu]

I was thinking about this issue, and I realized it does help to have all the real examples encoded in the spec tests

The one I added was this

# spaces help
good() {
  cputype=`( ( (grep cpu /proc/cpuinfo | cut -d: -f2) ; ($PRTDIAG -v |grep -i sparc) ; grep -i cpu /var/run/dmesg.boot ) | head -n 1) 2> /dev/null`
}

bad() {
  cputype=`(((grep cpu /proc/cpuinfo | cut -d: -f2) ; ($PRTDIAG -v |grep -i sparc) ; grep -i cpu /var/run/dmesg.boot ) | head -n 1) 2> /dev/null`
  #echo cputype=$cputype
}

The good one has spaces for ( ( (

---

But this one is slightly different, so I think it's useful to have it too. And to note that it came from gzip. (hm I didn't note which package the other error is from)

Because we don't know what the exact solution is yet.

But they should be in the same file, I guess spec/divergence is OK

[andychu]

So yeah I think having the exact line helps, and then we can reduce to something more minimal as we fix it

The reducing process is often how I figure out what the bug actually is

[melvinw]

Ah ok. I'll reopen this and plop it in spec/divergence

[andychu]

great thanks!