Reset foreground and background while only comma is specified

[SilverRainZ]

Currently irssi can not correctly process ^C, which is a valid mirc color code.

For ^C4,2ir^C,ssi, the foreground color was inherited and left a comma:

But ^C, has neither foreground nor background, it should be treated as same as ^C:

[ailin-nemui]

does anyone have a mIRC ready to compare if it should be ir,ssi or irssi? does this fix issue #740 ?

[SilverRainZ]

@ailin-nemui I have not a mIRC for testing so I only tested on hexchat and srain.
It really fixes #740.

[ailin-nemui]

we had this bug: irssi-import/bugs.irssi.org#250

here is the comparison: we need to fix something, but maybe differently:

[SilverRainZ]

The one on the right is mIRC? It does't regard the comma as part of color code in ^C,, which means that the foreground color is never inherited -- I think it is unreasonable.

[ailin-nemui]

I think mIRC is the "de facto" standard on mIRC colour codes so we may need to accept the fact that the foreground can not be inherited, ^C, is ^C then,...

[dequis]

irssi:

mirc 7.47:

hexchat

weechat

After doing this I realized there are other more interesting test cases up there. Welp. I'll get to that later.

Regardless of the decisions made here: any changes to this code must go through fuzzing before they are merged. This is particularly fragile code.

[ailin-nemui]

I think the changes itself are good code wise but they don't match mirc

[SilverRainZ]

Well, now it act like mirc.

[ailin-nemui]

how about this:

diff --git a/src/fe-common/core/formats.c b/src/fe-common/core/formats.c
index 005e6fb7..a340bffa 100644
--- a/src/fe-common/core/formats.c
+++ b/src/fe-common/core/formats.c
@@ -1072,7 +1072,8 @@ static void get_mirc_color(const char **str, int *fg_ret, int *bg_ret)
 	fg = fg_ret == NULL ? -1 : *fg_ret;
 	bg = bg_ret == NULL ? -1 : *bg_ret;
 
-	if (!i_isdigit(**str) && **str != ',') {
+	if (!i_isdigit(**str)) {
+		/* turn off color */
 		fg = -1;
 		bg = -1;
 	} else {
@@ -1085,11 +1086,8 @@ static void get_mirc_color(const char **str, int *fg_ret, int *bg_ret)
 				(*str)++;
 			}
 		}
-		if (**str == ',') {
+		if ((*str)[0] == ',' && i_isdigit((*str)[1])) {
 			/* background color */
-			if (!i_isdigit((*str)[1]))
-				bg = -1;
-			else {
 				(*str)++;
 				bg = **str-'0';
 				(*str)++;
@@ -1097,7 +1095,6 @@ static void get_mirc_color(const char **str, int *fg_ret, int *bg_ret)
 					bg = bg*10 + (**str-'0');
 					(*str)++;
 				}
-			}
 		}
 	}