From d8dc2a1d814a7fdc69215be382602435cdb7ae6a Mon Sep 17 00:00:00 2001
From: Martijn Dekker <martijn@inlv.org>
Date: Wed, 22 Jun 2022 17:02:25 +0100
Subject: [PATCH] sh_setenviron(): deactivate compound assignment prefix

Reproducers:

$ ksh -c 'typeset -a arr=( ( (a $(($(echo 1) + 1)) c)1))'
ksh: echo: arr[0]._AST_FEATURES=CONFORMANCE - ast UNIVERSE - ucb: cannot be an array
ksh: [1]=1: invalid variable name
$ ksh -c 'typeset -a arr=( (a $(($(echo 1) + 1)) c)1)'
ksh: echo: arr._AST_FEATURES=CONFORMANCE - ast UNIVERSE - ucb: is not an identifier
ksh: [1]=1: invalid variable name

src/cmd/ksh93/sh/name.c: sh_setenviron():
- Save and clear the current compound assignment prefix (sh.prefix)
  while assigning to the _AST_FEATURES variable.
---
 NEWS                            | 5 +++++
 src/cmd/ksh93/include/version.h | 2 +-
 src/cmd/ksh93/sh/name.c         | 4 ++++
 src/cmd/ksh93/tests/comvar.sh   | 9 +++++++++
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index b21cc6b59..30bf4199f 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,11 @@ 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.
 
+2022-06-22:
+
+- Fixed: 'echo' failed when used inside a command substitution that
+  is inside a nested compound assignment.
+
 2022-06-20:
 
 - Fixed a race condition that could cause redirections to fail with a
diff --git a/src/cmd/ksh93/include/version.h b/src/cmd/ksh93/include/version.h
index 84543317b..8f918ada4 100644
--- a/src/cmd/ksh93/include/version.h
+++ b/src/cmd/ksh93/include/version.h
@@ -23,7 +23,7 @@
 
 #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	"2022-06-20"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2022-06-22"	/* 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 ${.sh.version}, so don't change amount of whitespace. */
diff --git a/src/cmd/ksh93/sh/name.c b/src/cmd/ksh93/sh/name.c
index f6aa65b1c..9053365d0 100644
--- a/src/cmd/ksh93/sh/name.c
+++ b/src/cmd/ksh93/sh/name.c
@@ -3125,7 +3125,11 @@ char* sh_setenviron(const char *name)
 	register Namval_t *np;
 	if(name)
 	{
+		char *save_prefix = sh.prefix;
+		/* deactivate a possible compound assignment */
+		sh.prefix = NIL(char*);
 		np = nv_open(name,sh.var_tree,NV_EXPORT|NV_IDENT|NV_NOARRAY|NV_ASSIGN);
+		sh.prefix = save_prefix;
 		if(strchr(name,'='))
 			return(nv_getval(np));
 		_nv_unset(np,0);
diff --git a/src/cmd/ksh93/tests/comvar.sh b/src/cmd/ksh93/tests/comvar.sh
index a6a4b20c7..11118aa47 100755
--- a/src/cmd/ksh93/tests/comvar.sh
+++ b/src/cmd/ksh93/tests/comvar.sh
@@ -706,5 +706,14 @@ EOF
 	"$SHELL" -c "$compound_array"
 ) || err_exit 'unsetting an array turned into a compound variable fails'
 
+# ======
+# before 2022-06-22, this resulted in:
+#   ksh: echo: arr[0]._AST_FEATURES=CONFORMANCE - ast UNIVERSE - ucb: cannot be an array
+#   ksh: [1]=1: invalid variable name
+got=$(set +x; eval 'typeset -a arr=( ( (a $(($(echo 1) + 1)) c)1))' 2>&1; typeset -p arr)
+exp='typeset -a arr=(((a 2 c) 1) )'
+[[ $got == "$exp" ]] || err_exit "'echo' environment messed up by compound assignment" \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+
 # ======
 exit $((Errors<125?Errors:125))