zsh-users/21903: Fix ${...?...} in interactive shell.

On failure should abort back to top level, but we reset the error
flag around commands.  Add a hard error flag that's only reset at top level.

2 files changed, 15 insertions, 1 deletions

diff --git a/Src/subst.c b/Src/subst.c
index 1c2027f32..92fde4598 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2922,6 +2922,13 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
                 if (isset(EXECOPT)) {
                     *idend = '\0';
                     zerr("%s: %s", idbeg, *s ? s : "parameter not set");
+                    /*
+                     * In interactive shell we need to return to
+                     * top-level prompt --- don't clear this error
+                     * after handling a command as we do with
+                     * most errors.
+                     */
+                    errflag |= ERRFLAG_HARD;
                     if (!interact) {
                         if (mypid == getpid()) {
                             /*
diff --git a/Src/zsh.h b/Src/zsh.h
index 996bc3369..2dc5e7e2a 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -2807,7 +2807,14 @@ enum errflag_bits {
     /*
      * User interrupt.
      */
-    ERRFLAG_INT = 2
+    ERRFLAG_INT = 2,
+    /*
+     * Hard error --- return to top-level prompt in interactive
+     * shell.  In non-interactive shell we'll typically already
+     * have exited.  This is reset by "errflag = 0" in
+     * loop(toplevel = 1, ...).
+     */
+    ERRFLAG_HARD = 4
 };
 
 /***********/