From 8f14514661ea9e15fc71019de6bef02a4dd9b627 Mon Sep 17 00:00:00 2001
From: Martijn Dekker <martijn@inlv.org>
Date: Sat, 28 May 2022 00:02:46 +0100
Subject: [PATCH] set --default: properly restore ksh IFS behaviour (re:
 9e2a8c69)

Reproducer:

$ (IFS=$'\t\t'; val=$'\tone\t\ttwo\t'; set --posix; \
   set -- $val; echo $#; set --noposix; set -- $val; echo $#)
2
4   <== OK

$ (IFS=$'\t\t'; val=$'\tone\t\ttwo\t'; set --posix; \
   set -- $val; echo $#; set --default; set -- $val; echo $#)
2
2   <== bug

The output of the seconnd command line should be like the first.

When POSIX mode is turned off using 'set --noposix' (or 'set +o
posix'), sh.ifstable is invalidated as it needs to be repopulated
on the next field split to restore ksh-specific special handling of
a repeated $IFS whitespace character as non-whitespace. However,
when 'set --default' is used, this does not happen, which is a bug.

src/cmd/ksh93/sh/args.c: sh_argopts():
- While processing --default, when turning off SH_POSIX, call
  sh_invalidate_ifs() to invalidate sh.ifstable.
---
 NEWS                            | 6 ++++++
 src/cmd/ksh93/include/version.h | 2 +-
 src/cmd/ksh93/sh/args.c         | 6 ++++++
 src/cmd/ksh93/tests/posix.sh    | 3 +++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index c0fa3248d..16b751465 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,12 @@ For full details, see the git log at: https://github.com/ksh93/ksh/tree/1.0
 
 Any uppercase BUG_* names are modernish shell bug IDs.
 
+2022-05-27:
+
+- Fixed a bug introduced on 2022-03-05 where 'set --default', while turning
+  off the --posix option, did not re-enable the special handling of a repeated
+  $IFS whitespace character as non-whitespace.
+
 2022-05-25:
 
 - Fixed a bug introduced on 2021-02-20 that caused incorrect output for
diff --git a/src/cmd/ksh93/include/version.h b/src/cmd/ksh93/include/version.h
index d4af15fd8..e2bd413c8 100644
--- a/src/cmd/ksh93/include/version.h
+++ b/src/cmd/ksh93/include/version.h
@@ -21,7 +21,7 @@
 
 #define SH_RELEASE_FORK	"93u+m"		/* only change if you develop a new ksh93 fork */
 #define SH_RELEASE_SVER	"1.0.0-beta.2"	/* semantic version number: https://semver.org */
-#define SH_RELEASE_DATE	"2022-05-25"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2022-05-27"	/* must be in this format for $((.sh.version)) */
 #define SH_RELEASE_CPYR	"(c) 2020-2022 Contributors to ksh " SH_RELEASE_FORK
 
 /* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */
diff --git a/src/cmd/ksh93/sh/args.c b/src/cmd/ksh93/sh/args.c
index 5e8488553..36701ec96 100644
--- a/src/cmd/ksh93/sh/args.c
+++ b/src/cmd/ksh93/sh/args.c
@@ -170,8 +170,14 @@ int sh_argopts(int argc,register char *argv[])
 			{
 				register const Shtable_t *tp;
 				for(tp=shtab_options; o = tp->sh_number; tp++)
+				{
 					if(!(o&SH_COMMANDLINE) && (o&=0xff)!=SH_RESTRICTED && is_option(&newflags,o))
+					{
 						off_option(&newflags,o);
+						if(o==SH_POSIX)
+							sh_invalidate_ifs();
+					}
+				}
 			}
 			defaultflag++;
 		    	continue;
diff --git a/src/cmd/ksh93/tests/posix.sh b/src/cmd/ksh93/tests/posix.sh
index 91702deeb..8f98907ea 100644
--- a/src/cmd/ksh93/tests/posix.sh
+++ b/src/cmd/ksh93/tests/posix.sh
@@ -113,6 +113,9 @@ got=$(set --noposix; set $val; echo "$#")
 exp=5
 [[ $got == "$exp" ]] || err_exit "repeated IFS whitespace char (noposix): incorrect number of fields" \
 	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+got=$(set --default; set $val; echo "$#")
+[[ $got == "$exp" ]] || err_exit "repeated IFS whitespace char (default): incorrect number of fields" \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
 IFS=$' \t\n' # default
 
 # causes file descriptors > 2 to be left open when invoking another program;