additional changes to avoid array subscript double expansion in arithmetic contexts

builtins/common.c

@@ -1026,3 +1026,29 @@ builtin_unbind_variable (vname)
     }
   return (unbind_variable (vname));
 }
+
+/* **************************************************************** */
+/*								    */
+/*	    External interface to manipulate shell options	    */
+/*								    */
+/* **************************************************************** */
+
+#if defined (ARRAY_VARS)
+int
+set_expand_once (nval, uwp)
+     int nval, uwp;
+{
+  int oa;
+
+  oa = assoc_expand_once;
+#if 0	/* TAG:bash-5.2 */
+  if (shell_compatibility_level > 51)
+#endif
+    {
+      if (uwp)
+	unwind_protect_int (assoc_expand_once);
+      assoc_expand_once = nval;
+    }
+  return oa;
+}
+#endif

builtins/common.h

@@ -138,6 +138,10 @@ extern sh_builtin_func_t *builtin_address PARAMS((char *));
 extern sh_builtin_func_t *find_special_builtin PARAMS((char *));
 extern void initialize_shell_builtins PARAMS((void));
 
+#if defined (ARRAY_VARS)
+extern int set_expand_once PARAMS((int, int));
+#endif
+
 /* Functions from exit.def */
 extern void bash_logout PARAMS((void));
 
@@ -243,6 +247,11 @@ extern int loop_level;
 /* variables from shift.def */
 extern int print_shift_error;
 
+/* variables from shopt.def */
+#if defined (ARRAY_VARS)
+extern int expand_once_flag;
+#endif
+
 /* variables from source.def */
 extern int source_searches_cwd;
 extern int source_uses_path;

builtins/declare.def

@@ -408,6 +408,12 @@ declare_internal (list, local_var)
 #else
       assoc_noexpand = 0;
 #endif
+      /* XXX - we allow unbalanced brackets if assoc_noexpand is set, we count
+	 brackets and make sure they match if assoc_noexpand is not set. So we
+	 need to make sure we're checking assoc_noexpand and expand_once_flag
+	 for backwards compatibility. We also use assoc_noexpand below when
+	 we call assign_array_element, so we need to make sure they're
+	 consistent in how they count brackets. */
       offset = assignment (name, assoc_noexpand ? 2 : 0);
       aflags = 0;
       created_var = 0;

builtins/mkbuiltins.c

@@ -72,7 +72,8 @@ extern char *strcpy ();
 #define BUILTIN_FLAG_SPECIAL	0x01
 #define BUILTIN_FLAG_ASSIGNMENT 0x02
 #define BUILTIN_FLAG_LOCALVAR	0x04
-#define BUILTIN_FLAG_POSIX_BUILTIN 0x08
+#define BUILTIN_FLAG_POSIX_BUILTIN	0x08
+#define BUILTIN_FLAG_ARRAYREF_ARG	0x10
 
 #define BASE_INDENT	4
 
@@ -173,11 +174,22 @@ char *posix_builtins[] =
   (char *)NULL
 };
 
+/* The builtin commands that can take array references as arguments and pay
+   attention to `assoc_expand_once'. These are the ones that don't assign
+   values, but need to avoid double expansions. */
+char *arrayvar_builtins[] =
+{
+  "declare", "let", "local", "printf", "read", "test", "[",
+  "typeset", "unset", "wait",		/*]*/
+  (char *)NULL
+};
+	
 /* Forward declarations. */
 static int is_special_builtin ();
 static int is_assignment_builtin ();
 static int is_localvar_builtin ();
 static int is_posix_builtin ();
+static int is_arrayvar_builtin ();
 
 #if !defined (HAVE_RENAME)
 static int rename ();
@@ -831,6 +843,8 @@ builtin_handler (self, defs, arg)
     new->flags |= BUILTIN_FLAG_LOCALVAR;
   if (is_posix_builtin (name))
     new->flags |= BUILTIN_FLAG_POSIX_BUILTIN;
+  if (is_arrayvar_builtin (name))
+    new->flags |= BUILTIN_FLAG_ARRAYREF_ARG;
 
   array_add ((char *)new, defs->builtins);
   building_builtin = 1;
@@ -1111,7 +1125,7 @@ char *structfile_header[] = {
   "/* This file is manufactured by ./mkbuiltins, and should not be",
   "   edited by hand.  See the source to mkbuiltins for details. */",
   "",
-  "/* Copyright (C) 1987-2015 Free Software Foundation, Inc.",
+  "/* Copyright (C) 1987-2021 Free Software Foundation, Inc.",
   "",
   "   This file is part of GNU Bash, the Bourne Again SHell.",
   "",
@@ -1250,12 +1264,13 @@ write_builtins (defs, structfile, externfile)
 		  else
 		    fprintf (structfile, "(sh_builtin_func_t *)0x0, ");
 
-		  fprintf (structfile, "%s%s%s%s%s, %s_doc,\n",
+		  fprintf (structfile, "%s%s%s%s%s%s, %s_doc,\n",
 		    "BUILTIN_ENABLED | STATIC_BUILTIN",
 		    (builtin->flags & BUILTIN_FLAG_SPECIAL) ? " | SPECIAL_BUILTIN" : "",
 		    (builtin->flags & BUILTIN_FLAG_ASSIGNMENT) ? " | ASSIGNMENT_BUILTIN" : "",
 		    (builtin->flags & BUILTIN_FLAG_LOCALVAR) ? " | LOCALVAR_BUILTIN" : "",
 		    (builtin->flags & BUILTIN_FLAG_POSIX_BUILTIN) ? " | POSIX_BUILTIN" : "",
+		    (builtin->flags & BUILTIN_FLAG_ARRAYREF_ARG) ? " | ARRAYREF_BUILTIN" : "",
 		    document_name (builtin));
 
 		  /* Don't translate short document summaries that are identical
@@ -1645,6 +1660,13 @@ is_posix_builtin (name)
   return (_find_in_table (name, posix_builtins));
 }
 
+static int
+is_arrayvar_builtin (name)
+     char *name;
+{
+  return (_find_in_table (name, arrayvar_builtins));
+}
+
 #if !defined (HAVE_RENAME)
 static int
 rename (from, to)

builtins/set.def

@@ -959,8 +959,15 @@ unset_builtin (list)
 #if defined (ARRAY_VARS)
       if (var && unset_array)
 	{
+	  int tvflags;
+
+	  tvflags = vflags;
+#if 0	/* TAG:bash-5.2 */
+	  if (shell_compatibility_level <= 51)
+	    tvflags |= VA_ALLOWALL;
+#endif
 	  /* Let unbind_array_element decide what to do with non-array vars */
-	  tem = unbind_array_element (var, t, vflags);	/* XXX new third arg */
+	  tem = unbind_array_element (var, t, tvflags);	/* XXX new third arg */
 	  if (tem == -2 && array_p (var) == 0 && assoc_p (var) == 0)
 	    {
 	      builtin_error (_("%s: not an array variable"), var->name);

builtins/shopt.def

@@ -1,7 +1,7 @@
 This file is shopt.def, from which is created shopt.c.
 It implements the Bash `shopt' builtin.
 
-Copyright (C) 1994-2020 Free Software Foundation, Inc.
+Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -120,6 +120,7 @@ extern int debugging_mode;
 #if defined (ARRAY_VARS)
 extern int assoc_expand_once;
 extern int array_expand_once;
+int expand_once_flag;
 #endif
 
 #if defined (SYSLOG_HISTORY)
@@ -140,6 +141,10 @@ static int shopt_enable_hostname_completion PARAMS((char *, int));
 static int shopt_set_complete_direxpand PARAMS((char *, int));
 #endif
 
+#if defined (ARRAY_VARS)
+static int set_assoc_expand PARAMS((char *, int));
+#endif
+
 static int shopt_set_debug_mode PARAMS((char *, int));
 
 static int shopt_login_shell;
@@ -163,7 +168,7 @@ static struct {
 } shopt_vars[] = {
   { "autocd", &autocd, (shopt_set_func_t *)NULL },
 #if defined (ARRAY_VARS)
-  { "assoc_expand_once", &assoc_expand_once, (shopt_set_func_t *)NULL },
+  { "assoc_expand_once", &expand_once_flag, set_assoc_expand },
 #endif
   { "cdable_vars", &cdable_vars, (shopt_set_func_t *)NULL },
   { "cdspell", &cdspelling, (shopt_set_func_t *)NULL },
@@ -362,7 +367,7 @@ reset_shopt_options ()
 #endif
 
 #if defined (ARRAY_VARS)
-  assoc_expand_once = 0;
+  expand_once_flag = assoc_expand_once = 0;
 #endif
 
 #if defined (HISTORY)
@@ -897,3 +902,17 @@ initialize_bashopts (no_bashopts)
   /* Set up the $BASHOPTS variable. */
   set_bashopts ();
 }
+
+#if defined (ARRAY_VARS)
+static int
+set_assoc_expand (option_name, mode)
+     char *option_name;
+     int mode;
+{
+#if 0 /* TAG: bash-5.2, fix shell_compatibility_level test */
+  if (shell_compatibility_level <= 51)
+#endif
+    assoc_expand_once = expand_once_flag;
+  return 0;
+}
+#endif