[osh] YSH expr sub no longer does dynamic globbing

In YSH, it's a moot point because of simple word evaluation.  YSH never
does dynamic globbing.

In OSH, this behavior is more consistent with simple word evaluation.

[refactor] Introduce word_.PieceQuoted() to make this clear.

Author: Andy C

osh/word_.py

@@ -3,6 +3,7 @@
 """
 
 from _devbuild.gen.id_kind_asdl import Id, Kind, Id_t, Kind_t
+from _devbuild.gen.runtime_asdl import Piece
 from _devbuild.gen.syntax_asdl import (
     Token,
     CompoundWord,
@@ -29,6 +30,15 @@
 _ = log
 
 
+def PieceQuoted(s):
+    # type: (str) -> Piece
+    """
+    For 'hi' "$x" 
+    and $[myexpr] in YSH
+    """
+    return Piece(s, True, False)
+
+
 def LiteralId(part):
     # type: (word_part_t) -> Id_t
     """If the WordPart consists of a single literal token, return its Id.

osh/word_eval.py

@@ -1380,7 +1380,7 @@ def _EvalDoubleQuoted(self, parts, part_vals):
         # of (DoubleQuoted [Literal '']).  This is better but it means we
         # have to check for it.
         if len(parts) == 0:
-            v = Piece('', True, False)
+            v = word_.PieceQuoted('')
             part_vals.append(v)
             return
 
@@ -1782,6 +1782,7 @@ def _EvalExtGlob(self, part, part_vals):
         else:
             op_str = lexer.LazyStr(op)
         # Do NOT split these.
+        # TODO: should be PieceQuoted
         part_vals.append(Piece(op_str, False, False))
 
         for i, w in enumerate(part.arms):
@@ -1857,18 +1858,18 @@ def _EvalWordPart(self, part, part_vals, flags):
             elif case(word_part_e.BracedRangeDigit):
                 part = cast(word_part.BracedRangeDigit, UP_part)
                 # This is the '5' in {1..10} - whether it's quoted should not
-                # matter
+                # matter - it doesn't look like a glob
                 v = Piece(part.s, False, False)
                 part_vals.append(v)
 
             elif case(word_part_e.EscapedLiteral):
                 part = cast(word_part.EscapedLiteral, UP_part)
-                v = Piece(part.ch, True, False)
+                v = word_.PieceQuoted(part.ch)
                 part_vals.append(v)
 
             elif case(word_part_e.SingleQuoted):
                 part = cast(SingleQuoted, UP_part)
-                v = Piece(part.sval, True, False)
+                v = word_.PieceQuoted(part.sval)
                 part_vals.append(v)
 
             elif case(word_part_e.DoubleQuoted):
@@ -1904,7 +1905,7 @@ def _EvalWordPart(self, part, part_vals, flags):
                 # We never parse a quoted string into a TildeSub.
                 assert not quoted
                 s = self.tilde_ev.Eval(part)
-                v = Piece(s, True, False)  # NOT split even when unquoted!
+                v = word_.PieceQuoted(s)
                 part_vals.append(v)
 
             elif case(word_part_e.ArithSub):
@@ -2615,7 +2616,7 @@ def _EvalProcessSub(self, cs_part):
         # type: (CommandSub) -> Piece
         dev_path = self.shell_ex.RunProcessSub(cs_part)
         # pretend it's quoted; no split or glob
-        return Piece(dev_path, True, False)
+        return word_.PieceQuoted(dev_path)
 
 
 _DUMMY = '__NO_COMMAND_SUB__'
@@ -2659,7 +2660,7 @@ def _EvalCommandSub(self, cs_part, quoted):
     def _EvalProcessSub(self, cs_part):
         # type: (CommandSub) -> Piece
         # pretend it's quoted; no split or glob
-        return Piece('__NO_PROCESS_SUB__', True, False)
+        return word_.PieceQuoted('__NO_PROCESS_SUB__')
 
 
 # vim: sw=4

spec/osh-bugs.test.sh

@@ -29,3 +29,13 @@ pp test_ (x)
 ## STDOUT:
 ## END
 
+
+#### YSH $[expr_sub] in OSH should not do dynamic globbing
+
+touch {foo,bar}.txt
+
+echo $["*.txt"]
+
+## STDOUT:
+*.txt
+## END

ysh/expr_eval.py

@@ -52,13 +52,14 @@
 from core import num
 from core import pyutil
 from core import state
-from display import ui
 from core import vm
+from display import ui
 from data_lang import j8
 from frontend import lexer
 from frontend import match
 from frontend import typed_args
 from osh import braces
+from osh import word_
 from mycpp import mops
 from mycpp.mylib import log, NewDict, switch, tagswitch, print_stderr
 from ysh import func_proc
@@ -412,7 +413,7 @@ def EvalExprSub(self, part):
         with switch(part.left.id) as case:
             if case(Id.Left_DollarBracket):  # $[join(x)]
                 s = val_ops.Stringify(val, loc.WordPart(part), 'Expr sub ')
-                return Piece(s, False, False)
+                return word_.PieceQuoted(s)
 
             elif case(Id.Lit_AtLBracket):  # @[split(x)]
                 strs = val_ops.ToShellArray(val, loc.WordPart(part),