Bugs with (q-) parameter flag

Bugs with (q-) parameter flag

[Bart Schaefer]

Test case:

torch% x=( a '' '\b' 'c d' '$e' )

Baseline:

torch% print -rl ${(q)x}  
a
''
\\b
c\ d
\$e

I'm not certain this first one qualifies as a bug.  Is the empty string a
"special character"?

torch% print -rl ${(q-)x}
a
'\b'
'c d'
'$e'

Note that the empty string has disappeared.  Now for some other cases.
First, the expected behavior:

torch% print -rl ${(qq-)x}
zsh: error in flags

Next:

torch% print -rl ${(q-q)x}
'a'
''''
'\\b'
'c\ d'
'\$e'

I'm not sure exactly what's going on there.  It's not the same as either
${(qq)x} or ${(q)$(q-)x}} although it's close to ${(q-)${(q)x}} ... but
turning empty string into '''' can't possibly be right.

[ Incidentally although ${(q-)x} produces "the most readable output" for a
single depth, ${(q-)${(q-)x}} is less readable than ${(q)${(q-)x}} ]

torch% print -rl ${(q-qq)x}
 ../../zsh-4.0/Src/utils.c:4789: BUG: bad quote type in quotestring
 ../../zsh-4.0/Src/utils.c:4789: BUG: bad quote type in quotestring
 ../../zsh-4.0/Src/utils.c:4789: BUG: bad quote type in quotestring
 ../../zsh-4.0/Src/utils.c:4789: BUG: bad quote type in quotestring
 ../../zsh-4.0/Src/utils.c:4789: BUG: bad quote type in quotestring
'a'
''
'\b'
'c d'
'$e'

That one repeats no matter how many q you use, and you can use as many
of them as you want; ${(q-qqqqqq)x} is accepted.  Normally more than 4
repeats of q produces "error in flags".

Re: Bugs with (q-) parameter flag

[Peter Stephenson]

On Sat, 14 Apr 2012 10:27:12 -0700
Bart Schaefer <schaefer@brasslantern.com> wrote:
> torch% x=( a '' '\b' 'c d' '$e' )
>
> I'm not certain this first one qualifies as a bug.  Is the empty string a
> "special character"?
> 
> torch% print -rl ${(q-)x}
> a
> '\b'
> 'c d'
> '$e'

I don't think that can be right, it doesn't happen with any other form
of quoting.  It's got lost in the gaps between backslash and
double-quote handling.

Index: Src/subst.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/subst.c,v
retrieving revision 1.133
diff -p -u -r1.133 subst.c
--- Src/subst.c	29 Feb 2012 09:57:41 -0000	1.133
+++ Src/subst.c	16 Apr 2012 09:56:19 -0000
@@ -1828,6 +1828,10 @@ paramsubst(LinkList l, LinkNode n, char 
 			quotemod = 1;
 			quotetype = QT_SINGLE_OPTIONAL;
 		    } else {
+			if (quotetype == QT_SINGLE_OPTIONAL) {
+			    /* extra q's after '-' not allowed */
+			    goto flagerr;
+			}
 			quotemod++, quotetype++;
 		    }
 		    break;
Index: Src/utils.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/utils.c,v
retrieving revision 1.267
diff -p -u -r1.267 utils.c
--- Src/utils.c	13 Mar 2012 09:47:02 -0000	1.267
+++ Src/utils.c	16 Apr 2012 09:56:20 -0000
@@ -4735,7 +4735,7 @@ quotestring(const char *s, char **e, int
     char *v;
     int alloclen;
     char *buf;
-    int sf = 0, shownull;
+    int sf = 0, shownull = 0;
     /*
      * quotesub is used with QT_SINGLE_OPTIONAL.
      * quotesub = 0:  mechanism not active
@@ -4750,14 +4750,12 @@ quotestring(const char *s, char **e, int
     const char *uend;
 
     slen = strlen(s);
-    if (instring == QT_BACKSLASH_SHOWNULL) {
-	shownull = 1;
-	instring = QT_BACKSLASH;
-    } else {
-	shownull = 0;
-    }
     switch (instring)
     {
+    case QT_BACKSLASH_SHOWNULL:
+	shownull = 1;
+	instring = QT_BACKSLASH;
+	/*FALLTHROUGH*/
     case QT_BACKSLASH:
 	/*
 	 * With QT_BACKSLASH we may need to use $'\300' stuff.
@@ -4765,22 +4763,23 @@ quotestring(const char *s, char **e, int
 	 * storage and using heap for correct size at end.
 	 */
 	alloclen = slen * 7 + 1;
-	if (!*s && shownull)
-	    alloclen += 2;	/* for '' */
 	break;
 
     case QT_SINGLE_OPTIONAL:
 	/*
 	 * Here, we may need to add single quotes.
+	 * Always show empty strings.
 	 */
 	alloclen = slen * 4 + 3;
-	quotesub = 1;
+	quotesub = shownull = 1;
 	break;
 
     default:
 	alloclen = slen * 4 + 1;
 	break;
     }
+    if (!*s && shownull)
+	alloclen += 2;	/* for '' */
 
     quotestart = v = buf = zshcalloc(alloclen);
 
Index: Test/D04parameter.ztst
===================================================================
RCS file: /cvsroot/zsh/zsh/Test/D04parameter.ztst,v
retrieving revision 1.64
diff -p -u -r1.64 D04parameter.ztst
--- Test/D04parameter.ztst	10 Apr 2012 01:17:03 -0000	1.64
+++ Test/D04parameter.ztst	16 Apr 2012 09:56:20 -0000
@@ -385,6 +385,13 @@
 >$'playing \'stupid\' "games" \\w\\i\\t\\h $quoting.'
 >'playing '\'stupid\'' "games" \w\i\t\h $quoting.'
 
+  x=( a '' '\b' 'c d' '$e' )
+  print -r ${(q)x}
+  print -r ${(q-)x}
+0:Another ${(q...)...} test
+>a '' \\b c\ d \$e
+>a '' '\b' 'c d' '$e'
+
   print -r -- ${(q-):-foo}
   print -r -- ${(q-):-foo bar}
   print -r -- ${(q-):-"*(.)"}

-- 
Peter Stephenson <pws@csr.com>            Software Engineer
Tel: +44 (0)1223 692070                   Cambridge Silicon Radio Limited
Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, UK


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