fix for problem with command substitutions inside aliases

CWRU/CWRU.chlog

@@ -3914,3 +3914,21 @@ parse.y
 	  issue reported by Kerin Millar <kfm@plushkava.net>
 	- cond_term: restore extended_glob to a local copy; safer than using
 	  global_extglob, which we will reserve for error recovery
+
+				   8/30
+				   ----
+parse.y
+	- parse_comsub: don't clear the pushed string list; we might need it to
+	  consume additional input to satisfy this command substitution. When
+	  we restore the parser state, don't restore the pushed string list in
+	  case we used it. From
+	  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1018727
+	- parse_comsub: don't modify extended_glob if parser_state includes
+	  PST_EXTPAT, in which case we've already set extended_glob and
+	  global_extglob appropriately. Only matters in compatibility mode.
+
+				   8/31
+				   ----
+subst.c
+	- parameter_brace_transform: make sure we return an error if *xform
+	  is '\0'. Report from Ivan Kapranov <koltiradw@yandex.ru>

MANIFEST

@@ -1002,6 +1002,7 @@ tests/comsub2.sub	f
 tests/comsub3.sub	f
 tests/comsub4.sub	f
 tests/comsub5.sub	f
+tests/comsub6.sub	f
 tests/comsub-eof.tests	f
 tests/comsub-eof0.sub	f
 tests/comsub-eof1.sub	f

parse.y

@@ -4063,10 +4063,11 @@ parse_comsub (qc, open, close, lenp, flags)
      int *lenp, flags;
 {
   int peekc, r;
-  int start_lineno, local_extglob;
+  int start_lineno, local_extglob, was_extpat;
   char *ret, *tcmd;
   int retlen;
   sh_parser_state_t ps;
+  STRING_SAVER *saved_strings;
   COMMAND *saved_global, *parsed_command;
 
   /* Posix interp 217 says arithmetic expressions have precedence, so
@@ -4086,7 +4087,7 @@ parse_comsub (qc, open, close, lenp, flags)
 
   save_parser_state (&ps);
 
-  pushed_string_list = (STRING_SAVER *)NULL;
+  was_extpat = (parser_state & PST_EXTPAT);
 
   /* State flags we don't want to persist into command substitutions. */
   parser_state &= ~(PST_REGEXP|PST_EXTPAT|PST_CONDCMD|PST_CONDEXPR|PST_COMPASSIGN);
@@ -4098,6 +4099,8 @@ parse_comsub (qc, open, close, lenp, flags)
   /* State flags we want to set for this run through the parser. */
   parser_state |= PST_CMDSUBST|PST_EOFTOKEN|PST_NOEXPAND;
 
+  /* leave pushed_string_list alone, since we might need to consume characters
+     from it to satisfy this command substitution (in some perverse case). */
   shell_eof_token = close;
 
   saved_global = global_command;		/* might not be necessary */
@@ -4114,7 +4117,9 @@ parse_comsub (qc, open, close, lenp, flags)
   if (expand_aliases)
     expand_aliases = posixly_correct != 0;
 #if defined (EXTENDED_GLOB)
-  if (shell_compatibility_level <= 51)
+  /* If (parser_state & PST_EXTPAT), we're parsing an extended pattern for a
+     conditional command and have already set global_extglob appropriately. */
+  if (shell_compatibility_level <= 51 && was_extpat == 0)
     {
       local_extglob = global_extglob = extended_glob;
       extended_glob = 1;
@@ -4133,7 +4138,7 @@ parse_comsub (qc, open, close, lenp, flags)
     }
 
 #if defined (EXTENDED_GLOB)
-  if (shell_compatibility_level <= 51)
+  if (shell_compatibility_level <= 51 && was_extpat == 0)
     extended_glob = local_extglob;
 #endif
 
@@ -4161,7 +4166,7 @@ parse_comsub (qc, open, close, lenp, flags)
 	  shell_eof_token = ps.eof_token;
 	  expand_aliases = ps.expand_aliases;
 
-	  jump_to_top_level (DISCARD);
+	  jump_to_top_level (DISCARD);	/* XXX - return (&matched_pair_error)? */
 	}
     }
 
@@ -4180,7 +4185,12 @@ INTERNAL_DEBUG(("current_token (%d) != shell_eof_token (%c)", current_token, she
       return (&matched_pair_error);
     }
 
+  /* We don't want to restore the old pushed string list, since we might have
+     used it to consume additional input from an alias while parsing this
+     command substitution. */
+  saved_strings = pushed_string_list;
   restore_parser_state (&ps);
+  pushed_string_list = saved_strings;
 
   tcmd = print_comsub (parsed_command);		/* returns static memory */
   retlen = strlen (tcmd);

subst.c

@@ -8660,7 +8660,7 @@ parameter_brace_transform (varname, value, estatep, xform, rtype, quoted, pflags
       return ((char *)NULL);
     }
 
-  if (valid_parameter_transform (xform) == 0)
+  if (xform[0] == 0 || valid_parameter_transform (xform) == 0)
     {
       this_command_name = oname;
       if (vtype == VT_VARIABLE)

tests/RUN-ONE-TEST

@@ -1,4 +1,4 @@
-BUILD_DIR=/usr/local/build/chet/bash/bash-current
+BUILD_DIR=/usr/local/build/bash/bash-current
 THIS_SH=$BUILD_DIR/bash
 PATH=$PATH:$BUILD_DIR
 

tests/comsub.right

@@ -66,3 +66,14 @@ ok 7
 ok 9
 ok 8
 ok 8 
+Mon Aug 29 20:03:02 EDT 2022
+post foo
+Mon Aug 29 20:03:02 EDT 2022
+post foo1
+Mon Aug 29 20:03:02 EDT 2022
+Mon Aug 29 20:03:02 EDT 2022 after
+7
+Mon Aug 29 20:03:02 EDT 2022
+hey after x
+./comsub6.sub: line 40: syntax error near unexpected token `)'
+./comsub6.sub: line 40: `math1)'

tests/comsub.tests

@@ -81,3 +81,4 @@ ${THIS_SH} ./comsub2.sub
 ${THIS_SH} ./comsub3.sub
 ${THIS_SH} ./comsub4.sub
 ${THIS_SH} ./comsub5.sub
+${THIS_SH} ./comsub6.sub

tests/comsub6.sub

@@ -0,0 +1,40 @@
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+DATE='Mon Aug 29 20:03:02 EDT 2022'
+shopt -s expand_aliases
+
+alias foo='echo $(echo $DATE)'
+alias foo1='echo $(echo $DATE)    '
+
+foo
+echo post foo
+
+foo1
+echo post foo1
+
+alias comsub0='echo $(echo $DATE'
+comsub0)
+comsub0		) after
+
+alias math0='echo $(( 4+3 )'
+math0)
+
+alias x='VAR=$(echo hey)'
+x
+foo
+
+echo $VAR after x
+
+alias math1='echo $( date )'
+math1)

tests/new-exp.right

@@ -648,6 +648,7 @@ i
 declare -i foo
 A
 declare -A foo
+./new-exp10.sub: line 118: ${V@}: bad substitution
 abcxxxdef
 abcådef
 ḅć

tests/new-exp10.sub

@@ -113,3 +113,6 @@ declare -A foo
 echo ${foo@a}
 
 declare -p foo
+
+V=42
+echo ${V@}	# error

tests/new-exp14.sub

@@ -12,7 +12,7 @@
 #   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
-# test the other uses of the 'K' tranform operator and its sibling 'k'
+# test the other uses of the 'K' transform operator and its sibling 'k'
 # the associative array tests are performed separately, since that was the
 # original motivation for this feature
 foo=string