Merge branch 'typesettounset' into declarednull

Adds 'setopt typeset_to_unset', documentation, failure tests for POSIX incompatibilies, etc.

Completion/compinit

@@ -165,6 +165,7 @@ _comp_options=(
     NO_posixidentifiers
     NO_shwordsplit
     NO_shglob
+    NO_typesettounset
     NO_warnnestedvar
     NO_warncreateglobal
 )

Doc/Zsh/builtins.yo

@@ -1872,7 +1872,11 @@ ifnzman(noderef(Local Parameters))\
 retain their special attributes when made local.
 
 For each var(name)tt(=)var(value) assignment, the parameter
-var(name) is set to var(value).
+var(name) is set to var(value).  If the assignment is omitted and var(name)
+does em(not) refer to an existing parameter, a new parameter is intialized
+to empty string, zero, or empty array (as appropriate), em(unless) the
+shell option tt(TYPESET_TO_UNSET) is set.  When that option is set,
+the parameter attributes are recorded but the parameter remains unset.
 
 If the shell option tt(TYPESET_SILENT) is not set, for each remaining
 var(name) that refers to a parameter that is already set, the name and

Doc/Zsh/options.yo

@@ -1942,6 +1942,16 @@ If the option is set, they will only be shown when parameters are selected
 with the `tt(-m)' option.  The option `tt(-p)' is available whether or not
 the option is set.
 )
+pindex(TYPESET_TO_UNSET)
+pindex(NO_TYPESET_TO_UNSET)
+pindex(TYPESETTOUNSET)
+pindex(NOTYPESETTOUNSET)
+item(tt(TYPESET_TO_UNSET) <K> <S>)(
+When declaring a new parameter with any of the `tt(typeset)' family of
+related commands, the parameter remains unset unless and until a
+value is explicity assigned to it, either in the `tt(typeset)' command
+itself or as a later assignment statement.
+)
 pindex(VERBOSE)
 pindex(NO_VERBOSE)
 pindex(NOVERBOSE)

Src/builtin.c

@@ -2491,7 +2491,7 @@ typeset_single(char *cname, char *pname, Param pm, UNUSED(int func),
 		return NULL;
 	    }
 	}
-	if (isset(POSIXBUILTINS))
+	if (isset(TYPESETTOUNSET))
 	    pm->node.flags |= PM_DEFAULTED;
     } else {
 	if (idigit(*pname))

Src/options.c

@@ -259,6 +259,7 @@ static struct optname optns[] = {
 {{NULL, "transientrprompt",   0},			 TRANSIENTRPROMPT},
 {{NULL, "trapsasync",	      0},			 TRAPSASYNC},
 {{NULL, "typesetsilent",      OPT_EMULATE|OPT_BOURNE},	 TYPESETSILENT},
+{{NULL, "typesettounset",     OPT_EMULATE|OPT_BOURNE},	 TYPESETTOUNSET},
 {{NULL, "unset",	      OPT_EMULATE|OPT_BSHELL},	 UNSET},
 {{NULL, "verbose",	      0},			 VERBOSE},
 {{NULL, "vi",		      0},			 VIMODE},

Src/zsh.h

@@ -2538,6 +2538,7 @@ enum {
     TRANSIENTRPROMPT,
     TRAPSASYNC,
     TYPESETSILENT,
+    TYPESETTOUNSET,
     UNSET,
     VERBOSE,
     VIMODE,

Test/D06subscript.ztst

@@ -289,3 +289,8 @@ F:Regression test for workers/42297
 >14 24
 >b b
 >b?rbaz foob?r
+
+  i=1,3
+  [[ ${a[$i]} = ${a[i]} ]]
+0f:Math evaluation of commas in array subscripts
+F:In math, (($i)) should be the same as ((i)), see workers/47748.

Test/E03posix.ztst

@@ -4,7 +4,7 @@
 #
 
 %prep
- setopt POSIX_BUILTINS
+ setopt POSIX_BUILTINS TYPESET_TO_UNSET
 
 %test
 
@@ -117,3 +117,47 @@
   }
 0:readonly with typeset -p
 >typeset -g -r var
+
+# Tests expected to fail
+
+  echo -
+0f:A single "-" for echo does not end the arguments
+F:POSIX requires a solitary "-" to be a plain argument
+>-
+
+  ARGV0=sh $ZTST_testdir/../Src/zsh -c 'foreach() { true; }'
+-f:"foreach" is not a reserved word
+
+  ARGV0=sh $ZTST_testdir/../Src/zsh -c 'end() { true; }
+-f:"end" is not a reserved word
+
+  a='a:b:' ARGV0=sh $ZTST_testdir/../Src/zsh -c 'IFS=:; printf "<%s>\n" $a'
+0f:IFS is a separator, not a delimiter
+><a>
+><b>
+
+  a=$'\ra\r\rb' ARGV0=sh $ZTST_testdir/../Src/zsh -c 'IFS=:; printf "<%s>\n" $a'
+0f:All whitespace characters are "IFS whitespace"
+F:isspace('\r') is true so \r should behave like space, \t, \n
+F:This may also need to apply to multibyte whitespace
+><a>
+><b>
+
+  ARGV0=sh $ZTST_testdir/../Src/zsh -c 'IFS=2; printf "<%s>\n" $((11*11))'
+0f:IFS applies to math results (numbers treated as strings)
+><1>
+><1>
+
+  ARGV0=sh $ZTST_testdir/../Src/zsh -c 'inf=42; echo $((inf))'
+0f:All identifiers are variable references in POSIX arithmetic
+F:POSIX has neither math functions nor floating point
+>42
+
+  ARGV0=sh $ZTST_testdir/../Src/zsh -c 'EUID=10; echo "$EUID"'
+-f:EUID is not a special variable
+>10
+
+  ARGV0=sh $ZTST_testdir/../Src/zsh -c "printf '<%10s>\n' St$'\M-C\M-)'phane"
+0f:Width of %s is computed in bytes not characters
+F:This is considered a bugfix in zsh
+><  Stéphane>