[spec/introspect] Stub out shopt -s compat_array and add failing test.

frontend/option_def.py

@@ -229,9 +229,9 @@ def _Init(opt_def):
   # shopt options that aren't in any groups.
   opt_def.Add('failglob')  # not implemented.
 
-  # TODO: Rename eval_unsafe_arith
   opt_def.Add('eval_unsafe_arith')  # recursive parsing and evaluation (ble.sh)
-  opt_def.Add('parse_dynamic_arith')  # dyanmic LHS
+  opt_def.Add('parse_dynamic_arith')  # dynamic LHS
+  opt_def.Add('compat_array')  # ${array} is ${array[0]}
 
   # Two strict options that from bash's shopt
   for name in ['nullglob', 'inherit_errexit']:

spec/introspect.test.sh

@@ -139,14 +139,37 @@ ____
 ['11']
 ## END
 
+
 #### ${FUNCNAME} with prefix/suffix operators (OSH regression)
+shopt -s compat_array
+
+check() {
+  argv.py "${#FUNCNAME}"
+  argv.py "${FUNCNAME::1}"
+  argv.py "${FUNCNAME:1}"
+}
+check
+## STDOUT:
+['5']
+['c']
+['heck']
+## END
+
+#### operators on FUNCNAME not allowed by default
 check() {
+  argv.py "${FUNCNAME}"
   argv.py "${#FUNCNAME}"
   argv.py "${FUNCNAME::1}"
   argv.py "${FUNCNAME:1}"
 }
 check
+## status: 1
 ## STDOUT:
+['check']
+## END
+## OK bash status: 0
+## OK bash STDOUT:
+['check']
 ['5']
 ['c']
 ['heck']

test/spec.sh

@@ -533,7 +533,7 @@ special-vars() {
 }
 
 introspect() {
-  sh-spec spec/introspect.test.sh --no-cd-tmp \
+  sh-spec spec/introspect.test.sh --no-cd-tmp --osh-failures-allowed 1 \
     $BASH $OSH_LIST "$@"
 }