Fix bug with ${x/#/replace} caught by wild tests.

Also, fix a bug in the prior OSH implementation.  The negative index
was wrong in the case of an empty pattern.

core/libstr.py

@@ -274,21 +274,22 @@ def Replace(self, s, op):
class _ConstStringReplacer(_Replacer):
  def __init__(self, pat, replace_str):
    self.pat = pat
    self.pat_len = len(pat)
    self.replace_str = replace_str

  def Replace(self, s, op):
    if op.do_all:
      return s.replace(self.pat, self.replace_str)
    elif op.do_prefix:
      if s.startswith(self.pat):
        n = len(self.pat)
        return self.replace_str + s[n:]
        return self.replace_str + s[self.pat_len:]
      else:
        return s
    elif op.do_suffix:
      if s.endswith(self.pat):
        n = len(self.pat)
        return s[:-n] + self.replace_str
        # NOTE: This handles ${s/#/foo}.  See spec test in var-op-strip.
        i = len(s) - self.pat_len
        return s[:i] + self.replace_str
      else:
        return s
    else:

osh/word_parse.py

@@ -232,10 +232,8 @@ def _ReadPatSubVarOp(self, lex_mode):
        do_suffix = True
        pat.parts.pop(0)

    if len(pat.parts) == 0:
      # TODO: Print the modifier better.
      p_die('Pattern in ${x/pat/replace} must not be empty (got modifier %s)',
            first_part, token=self.cur_token)
    # NOTE: If there is a modifier, the pattern can be empty, e.g.
    # ${s/#/foo} and ${a/%/foo}.

    if self.token_type == Id.Right_VarSub:
      # e.g. ${v/a} is the same as ${v/a/}  -- empty replacement string

spec/var-op-strip.test.sh

@@ -85,5 +85,25 @@ argv.py "${s%%abcde}" "${s%abcde}" "${s#abcde}" "${s##abcde}"
['abcd', 'abcd', 'abcd', 'abcd']
## END

#### Prepend using replacement of #
# This case was found in Kubernetes and others
array=(aa bb '')
argv.py ${array[@]/#/prefix-}
## STDOUT:
['prefix-aa', 'prefix-bb', 'prefix-']
## END
## N-I dash status: 2
## N-I dash stdout-json: ""
## N-I mksh status: 1
## N-I mksh stdout-json: ""


#### Append using replacement of %
array=(aa bb '')
argv.py ${array[@]/%/-suffix}
## STDOUT:
['aa-suffix', 'bb-suffix', '-suffix']
## END
## N-I dash status: 2
## N-I dash stdout-json: ""
## N-I mksh status: 1
## N-I mksh stdout-json: ""

test/parse-errors.sh

@@ -130,6 +130,10 @@ arith-expr() {
  _error-case '$(( ` ))'

  _error-case '$(( $ ))'

  # "Can't assign to None" is misleading.
  # From wild/src/distro/portage/bin/helper-functions.sh
  _error-case '$(( ${var} = fd ))'
}

bool-expr() {