Re: [bug] busyloop upon $=var with NULs when $IFS contains both NUL and a byte > 0x7f

["Jun. T" <takimoto-j@xxxxxxxxxxxxxxxxx>]

> 2022/11/18 23:27, Stephane Chazelas <stephane@xxxxxxxxxxxx> wrote:
> 
> With +o multibyte, no busy loop, but splitting doesn't work properly:
> 
> $ LC_ALL=C zsh +o multibyte -c 'IFS=é$IFS; printf "<%q>\n" $=IFS'
> <$'\303'$'\251'>
> <''>

It seems this can be fixed by the following patch
(use the multibyte code only if MULTIBYTE option is on).

The test script above gives
<''>
<''>
<''>
<''>

I gess this is the expected result (the description of IFS in man
zshparam(1) is not easy to understand).

If this works OK, then I think we can force reset IFS if an invalid
character is found in it when multibyte option is on, because
if a user wants (in C locale) to include any byte in IFS then she/he
can unset multibyte option.



diff --git a/Src/utils.c b/Src/utils.c
index edf5d3df7..a182553e7 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -74,9 +74,6 @@ set_widearray(char *mb_array, Widechar_array wca)
     }
     wca->len = 0;
 
-    if (!isset(MULTIBYTE))
-	return;
-
     if (mb_array) {
 	VARARR(wchar_t, tmpwcs, strlen(mb_array));
 	wchar_t *wcptr = tmpwcs;
@@ -4118,8 +4115,9 @@ inittyptab(void)
      * having IIDENT here is a good idea at all, but this code
      * should disappear into history...
      */
-    for (t0 = 0240; t0 != 0400; t0++)
-	typtab[t0] = IALPHA | IALNUM | IIDENT | IUSER | IWORD;
+    if isset(MULTIBYTE)
+	for (t0 = 0240; t0 != 0400; t0++)
+	    typtab[t0] = IALPHA | IALNUM | IIDENT | IUSER | IWORD;
 #endif
     /* typtab['.'] |= IIDENT; */ /* Allow '.' in variable names - broken */
     typtab['_'] = IIDENT | IUSER;
@@ -4138,7 +4136,7 @@ inittyptab(void)
 	DEFAULT_IFS_SH : DEFAULT_IFS; *s; s++) {
 	int c = STOUC(*s == Meta ? *++s ^ 32 : *s);
 #ifdef MULTIBYTE_SUPPORT
-	if (!isascii(c)) {
+	if (isset(MULTIBYTE) && !isascii(c)) {
 	    /* see comment for wordchars below */
 	    continue;
 	}
@@ -4154,7 +4152,7 @@ inittyptab(void)
     for (s = wordchars ? wordchars : DEFAULT_WORDCHARS; *s; s++) {
 	int c = STOUC(*s == Meta ? *++s ^ 32 : *s);
 #ifdef MULTIBYTE_SUPPORT
-	if (!isascii(c)) {
+	if (isset(MULTIBYTE) && !isascii(c)) {
 	    /*
 	     * If we have support for multibyte characters, we don't
 	     * handle non-ASCII characters here; instead, we turn
@@ -4168,9 +4166,11 @@ inittyptab(void)
 	typtab[c] |= IWORD;
     }
 #ifdef MULTIBYTE_SUPPORT
-    set_widearray(wordchars, &wordchars_wide);
-    set_widearray(ifs ? ifs : EMULATION(EMULATE_KSH|EMULATE_SH) ?
-	DEFAULT_IFS_SH : DEFAULT_IFS, &ifs_wide);
+    if (isset(MULTIBYTE)) {
+	set_widearray(wordchars, &wordchars_wide);
+	set_widearray(ifs ? ifs : EMULATION(EMULATE_KSH|EMULATE_SH) ?
+	    DEFAULT_IFS_SH : DEFAULT_IFS, &ifs_wide);
+    }
 #endif
     for (s = SPECCHARS; *s; s++)
 	typtab[STOUC(*s)] |= ISPECIAL;