Fix 'unset R' where R is readonly.

OSH was too strict, and it caused the Aboriginal run to fail, because it
tries to 'unset SHELLOPTS'.

We have to rely on 'errexit' for a lot of strictness.

Also:
- add 2 shells snippets that OSH should fail on but doesn't.
- strict-options.test.sh uses the new spec test format.

core/builtin.py

@@ -839,10 +839,16 @@ def Unset(argv, mem, funcs):
      if name in funcs:
        del funcs[name]
    elif arg.v:
      mem.Unset(runtime.LhsName(name), scope_e.Dynamic)
      ok, _  = mem.Unset(runtime.LhsName(name), scope_e.Dynamic)
      if not ok:
        util.error("Can't unset readonly variable %r", name)
        return 1
    else:
      # Try to delete var first, then func.
      found = mem.Unset(runtime.LhsName(name), scope_e.Dynamic)
      ok, found = mem.Unset(runtime.LhsName(name), scope_e.Dynamic)
      if not ok:
        util.error("Can't unset readonly variable %r", name)
        return 1
      #log('%s: %s', name, found)
      if not found:
        if name in funcs:

core/state.py

@@ -623,17 +623,21 @@ def GetVar(self, name, lookup_mode=scope_e.Dynamic):
  def Unset(self, lval, lookup_mode):
    """
    Returns:
      Success or failure.  A non-existent variable is still considered success.
      ok bool, found bool.

      ok is false if the cell is read-only.
      found is false if the name is not there.
    """
    if lval.tag == lvalue_e.LhsName:  # unset x
      cell, namespace = self._FindCellAndNamespace(lval.name, lookup_mode)
      if cell:
        found = True
        if cell.readonly:
          e_die("Can't unset readonly variable %r", lval.name)
          return False, found
        del namespace[lval.name]  # it must be here
        return True  # found
        return True, found # found
      else:
        return False
        return True, False

    elif lval.tag == lvalue_e.LhsIndexedName:  # unset a[1]
      raise NotImplementedError

spec/builtin-vars.test.sh

@@ -153,11 +153,10 @@ echo status=$?
readonly R=foo
unset R
echo status=$?
# status: 1
# stdout-json: ""
# status: 0
# stdout: status=1
# OK dash status: 2
# BUG mksh/bash stdout-json: "status=1\n"
# BUG mksh/bash status: 0
# OK dash stdout-json: ""

### Unset a function without -f
f() {

spec/parse-errors.test.sh

@@ -103,3 +103,16 @@ f() {
echo a(b)
# status: 2
# OK mksh status: 1

### incomplete command sub
$(x
# status: 2
# OK mksh status: 1

### misplaced ;;
echo 1 ;; echo 2
# stdout-json: ""
# status: 2
# OK mksh status: 1

spec/strict-options.test.sh

@@ -1,46 +1,65 @@
#!/usr/bin/env bash

### Sourcing a script that returns is allowed no matter what
### Sourcing a script that returns at the top level
echo one
. spec/testdata/return-helper.sh
echo $?
echo two
# stdout-json: "one\nreturn-helper.sh\n42\ntwo\n"
## STDOUT:
one
return-helper.sh
42
two
## END

### top level control flow
$SH spec/testdata/top-level-control-flow.sh
# stdout-json: "SUBSHELL\nBREAK\nCONTINUE\nRETURN\n"
# OK bash stdout-json: "SUBSHELL\nBREAK\nCONTINUE\nRETURN\nDONE\n"
# status: 0
## status: 0
## STDOUT:
SUBSHELL
BREAK
CONTINUE
RETURN
## OK bash STDOUT:
SUBSHELL
BREAK
CONTINUE
RETURN
DONE
## END

### errexit and top-level control flow
$SH -o errexit spec/testdata/top-level-control-flow.sh
# stdout-json: "SUBSHELL\n"
# status: 2
# OK bash status: 1
## status: 2
## OK bash status: 1
## STDOUT:
SUBSHELL
## END

### set -o strict-control-flow
$SH -o strict-control-flow -c 'echo break; break; echo hi'
# stdout: break
# status: 1
# N-I dash/bash status: 2
# N-I dash/bash stdout-json: ""
# N-I mksh status: 1
# N-I mksh stdout-json: ""
## stdout: break
## status: 1
## N-I dash/bash status: 2
## N-I dash/bash stdout-json: ""
## N-I mksh status: 1
## N-I mksh stdout-json: ""

### return at top level is an error
return
echo "status=$?"
# stdout-json: ""
# OK bash stdout-json: "status=1\n"
## stdout-json: ""
## OK bash STDOUT:
status=1
## END

### continue at top level is NOT an error
# NOTE: bash and mksh both print warnings, but don't exit with an error.
continue
echo status=$?
# stdout: status=0
## stdout: status=0

### break at top level is NOT an error
break
echo status=$?
# stdout: status=0
## stdout: status=0

test/spec.sh

@@ -338,7 +338,7 @@ explore-parsing() {
}

parse-errors() {
  sh-spec spec/parse-errors.test.sh --osh-failures-allowed 3 \
  sh-spec spec/parse-errors.test.sh --osh-failures-allowed 5 \
    ${REF_SHELLS[@]} $OSH "$@"
}