Revert "41499 (with one further tweak): POSIX_STRINGS behaviour."

This reverts commit 2eacbef919.

Conflicts:
	ChangeLog

ChangeLog

@@ -1,3 +1,8 @@
+2017-08-08  Peter Stephenson  <p.w.stephenson@ntlworld.com>
+
+	* unposted: back off 41499 as it has side effects which, while
+	perfectly logical, are not what POSIX expects.
+
 2017-08-08  Peter Stephenson  <p.stephenson@samsung.com>
 
 	* 41510: Doc/Zsh/params.yo: update doc for $ZSH_PATCHLEVEL.

Doc/Zsh/options.yo

@@ -2193,16 +2193,16 @@ cindex(discarding embedded nulls in $'...')
 cindex(embedded nulls, in $'...')
 cindex(nulls, embedded in $'...')
 item(tt(POSIX_STRINGS) <K> <S>)(
-This option affects processing of quoted strings, and also
+This option affects processing of quoted strings.  Currently it only
-splitting of strngs.
+affects the behaviour of null characters, i.e. character 0 in the
+portable character set corresponding to US ASCII.
 
-When this option is not set, null characters (character 0 in the
+When this option is not set, null characters embedded within strings
-portable character set coresponding to US ASCII) that are embedded
+of the form tt($')var(...)tt(') are treated as ordinary characters. The
-within strings of the form tt($')var(...)tt(') are treated as ordinary
+entire string is maintained within the shell and output to files where
-characters. The entire string is maintained within the shell and output
+necessary, although owing to restrictions of the library interface
-to files where necessary, although owing to restrictions of the library
+the string is truncated at the null character in file names, environment
-interface the string is truncated at the null character in file names,
+variables, or in arguments to external programs.
-environment variables, or in arguments to external programs.
 
 When this option is set, the tt($')var(...)tt(') expression is truncated at
 the null character.  Note that remaining parts of the same string
@@ -2211,18 +2211,6 @@ beyond the termination of the quotes are not truncated.
 For example, the command line argument tt(a$'b\0c'd) is treated with
 the option off as the characters tt(a), tt(b), null, tt(c), tt(d),
 and with the option on as the characters tt(a), tt(b), tt(d).
-
-Furthermore, when the option is set, a trailing separator followed by an
-empty strings does not cause extra fields to be produced when the string
-is split.  For example,
-
-example(var="foo bar "
-print -l "${=var}")
-
-outputs a blank line at the end if tt(POSIXSTRINGS) is not set, but
-no blank line if the option is set.  Note that empty elements would in
-any case be removed if quotation marks were not used.  If the separator
-is not white space, only the final separator is ignored in this fashion.
 )
 pindex(POSIX_TRAPS)
 pindex(NO_POSIX_TRAPS)

Src/utils.c

@@ -3500,12 +3500,12 @@ skipwsep(char **s)
 mod_export char **
 spacesplit(char *s, int allownull, int heap, int quote)
 {
-    char *t, **ret, **ptr, **eptr;
+    char *t, **ret, **ptr;
     int l = sizeof(*ret) * (wordcount(s, NULL, -!allownull) + 1);
     char *(*dup)(const char *) = (heap ? dupstring : ztrdup);
 
     /* ### TODO: s/calloc/alloc/ */
-    eptr = ptr = ret = (char **) (heap ? hcalloc(l) : zshcalloc(l));
+    ptr = ret = (char **) (heap ? hcalloc(l) : zshcalloc(l));
 
     if (quote) {
 	/*
@@ -3537,7 +3537,6 @@ spacesplit(char *s, int allownull, int heap, int quote)
 	if (s > t || allownull) {
 	    *ptr = (char *) (heap ? zhalloc((s - t) + 1) :
 		                     zalloc((s - t) + 1));
-	    eptr = ptr;
 	    ztrncpy(*ptr++, t, s - t);
 	} else
 	    *ptr++ = dup(nulstring);
@@ -3546,21 +3545,6 @@ spacesplit(char *s, int allownull, int heap, int quote)
     }
     if (!allownull && t != s)
 	*ptr++ = dup("");
-    if (isset(POSIXSTRINGS) && ptr > eptr + 1) {
-	/*
-	 * Trailing separators do not generate extra fields in POSIX.
-	 * Note this is only the final separator --- if the
-	 * immediately preceding field was null it is still counted.
-	 * So just back up one.
-	 */
-	--ptr;
-	if (!heap) {
-	    char **ret2 = realloc(ret, sizeof(*ret) * (ptr+1-ret));
-	    ptr -= ret-ret2;
-	    free(ret);
-	    ret = ret2;
-	}
-    }
     *ptr = NULL;
     return ret;
 }

Test/E01options.ztst

@@ -1339,44 +1339,3 @@
 ?(anon):4: `break' active at end of function scope
 ?(anon):4: `break' active at end of function scope
 ?(anon):4: `break' active at end of function scope
-
-  for opt in POSIX_STRINGS NO_POSIX_STRINGS; do
-    var="foo bar "
-    (setopt $opt; print -l X "${=var}" Y)
-    var="foo2::bar2:"
-    (setopt $opt; IFS=:; print -l X "${=var}" Y)
-    var="foo3:bar3::"
-    (setopt $opt; IFS=:; print -l X "${=var}" Y)
-  done
-0:POSIX_STRINGS effect on final delimiters
->X
->foo
->bar
->Y
->X
->foo2
->
->bar2
->Y
->X
->foo3
->bar3
->
->Y
->X
->foo
->bar
->
->Y
->X
->foo2
->
->bar2
->
->Y
->X
->foo3
->bar3
->
->
->Y