Re: PATCH: complist with long display lines

[Bart Schaefer <schaefer@brasslantern.com>]

On Aug 9, 11:04pm, Peter Stephenson wrote:
}
} The main completion code doesn't count an extra line for the screen for
} strings that exactly fit the screen width
} 
} The complist code, however, adds 1 to the count of lines (variously held
} in ml and mlprinted) if the number of columns just reaches the screen
} width.  As it only allocates the number of lines that the main
} completion code tells it, this causes bad array addressing.

Brilliant, Peter.  How did you ever track this down?

It may be worthwhile (or at least satisfying to paranoid types) to add
the following patch, which I've had sitting around uncommitted because
it failed to resolve the addressing issues that you seem to finally
have identified.  This patch prevents the infinite loop alluded to in
21842, by catching cases where an array index starts out negative and
decrements from there.  It might be unnecessary now, but:

Index: Src/Zle/complist.c
--- Src/Zle/complist.c	2006-08-10 00:34:13.000000000 -0700
+++ Src/Zle/complist.c.defense	2006-08-10 21:19:26.000000000 -0700
@@ -841,7 +831,7 @@
     selectlocalmap(NULL);
     settyinfo(&shttyinfo);
     putc('\r', shout);
-    for (i = columns - 1; i--; )
+    for (i = columns - 1; i-- > 0; )
 	putc(' ', shout);
     putc('\r', shout);
 
@@ -1162,7 +1148,7 @@
 		    if (mselect >= 0) {
 			int mm = (mcols * ml), i;
 
-			for (i = mcols; i--; ) {
+			for (i = mcols; i-- > 0; ) {
			    DPUTS(mm+i >= mgtabsize, "BUG: invalid position");
 			    mtab[mm + i] = mtmark(NULL);
 			    mgtab[mm + i] = mgmark(NULL);
@@ -1484,13 +1469,13 @@
 	    int mm = (mcols * ml), i;
 
             if (m->flags & CMF_DUMMY) {
-                for (i = mcols; i--; ) {
+                for (i = mcols; i-- > 0; ) {
		    DPUTS(mm+i >= mgtabsize, "BUG: invalid position");
                     mtab[mm + i] = mtmark(mp);
                     mgtab[mm + i] = mgmark(g);
                 }
             } else {
-                for (i = mcols; i--; ) {
+                for (i = mcols; i-- > 0; ) {
		    DPUTS(mm+i >= mgtabsize, "BUG: invalid position");
                     mtab[mm + i] = mp;
                     mgtab[mm + i] = g;
@@ -1545,13 +1523,13 @@
 	    int mm = mcols * ml, i;
 
             if (m->flags & CMF_DUMMY) {
-                for (i = (width ? width : mcols); i--; ) {
+                for (i = (width ? width : mcols); i-- > 0; ) {
		    DPUTS(mx+mm+i >= mgtabsize, "BUG: invalid position");
                     mtab[mx + mm + i] = mtmark(mp);
                     mgtab[mx + mm + i] = mgmark(g);
                 }
             } else {
-                for (i = (width ? width : mcols); i--; ) {
+                for (i = (width ? width : mcols); i-- > 0; ) {
		    DPUTS(mx+mm+i >= mgtabsize, "BUG: invalid position");
                     mtab[mx + mm + i] = mp;
                     mgtab[mx + mm + i] = g;
@@ -2184,7 +2142,7 @@
 	    Cmatch **p = mtab;
 
 	    for (y = 0; y < mlines; y++) {
-		for (x = mcols; x; x--, p++)
+		for (x = mcols; x > 0; x--, p++)
 		    if (*p && !mmarked(*p) && **p && mselect == (**p)->gnum)
 			break;
 		if (x) {
@@ -2195,7 +2153,7 @@
 	    int c;
 
 	    while (mlbeg) {
-		for (q = p, c = columns; c; q++, c--)
+		for (q = p, c = columns; c > 0; q++, c--)
 		    if (*q && !mmarked(*q))
 			break;
 		if (c)
@@ -2228,7 +2180,7 @@
 	    int c;
 
 	    while (mlbeg < mlines) {
-		for (q = p, c = columns; c; q++, c--)
+		for (q = p, c = columns; c > 0; q++, c--)
 		    if (*q)
 			break;
 		if (c)