From: Stefan Sperling <stsp@stsp.name>
Subject: Re: tog: fix display of lines ending in \r\n
To: Christian Weisgerber <naddy@mips.inka.de>, gameoftrees@openbsd.org
Date: Thu, 10 Dec 2020 23:52:04 +0100

On Thu, Dec 10, 2020 at 11:34:21PM +0100, Stefan Sperling wrote:
> On Thu, Dec 10, 2020 at 11:17:48PM +0100, Christian Weisgerber wrote:
> > Stefan Sperling:
> > 
> > > What specific problem are you looking at?
> > 
> > tog's log view dealing with the attached repository.
> > 
> > There are two ESC characters in the commit message.  They are escaped
> > to "^[", but then the next line is offset by 4 characters.
> > 
> > This would be consistent with ESC being handled as a zero-width
> > character, and a later instance (curses itself?) turning them into
> > visible sequences.
> 
> One thing we could do is this. Keeps the display intact, at least.

For some reason, Tab is both whitespace and control character :-/
This version fixes all Tabs in diffs being replaced by '?'.

diff 0e61ae21efda7ecccd19cccda1393f80ca90f9fd 5ec52daf04c1e30b62cc53dd4b51767bb4c20132
blob - ee044a71602208bed395a517f0354d580be3407f
blob + cc5cc30aef358c4400940c48e94d842f5b3a264a
--- tog/tog.c
+++ tog/tog.c
@@ -19,6 +19,7 @@
 #include <sys/ioctl.h>
 
 #include <ctype.h>
+#include <wctype.h>
 #include <errno.h>
 #define _XOPEN_SOURCE_EXTENDED
 #include <curses.h>
@@ -1175,8 +1176,12 @@ format_line(wchar_t **wlinep, int *widthp, const char 
 
 	i = 0;
 	while (i < wlen) {
-		int width = wcwidth(wline[i]);
+		int width;
 
+		if (!iswspace(wline[i]) && iswcntrl(wline[i]))
+			wline[i] = L'?';
+
+		width = wcwidth(wline[i]);
 		if (width == 0) {
 			i++;
 			continue;