[PATCH] zexit: don't write history in sub-shells

i noticed this:

  % read -t10 -k1 &
  [1] 13722
  [1]  + suspended (tty output)  read -t10 -k1
  % kill -HUP %%
  zsh: locking failed for /.../.zhistory: file exists
  [1]  + exit 1     read -t10 -k1

i think the lock failure is because both the sub-shell exiting and the
command executing want to save the history

in any case, i'm not sure why we should write the history out when a
sub-shell exits at all. is there a reason i'm not considering?

dana


diff --git a/Src/builtin.c b/Src/builtin.c
index b3a735fd4..6c7633dbf 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -6067,7 +6067,7 @@ zexit(int val, enum zexit_t from_where)
 	killrunjobs(from_where == ZEXIT_SIGNAL);
     }
     cleanfilelists();
-    if (isset(RCS) && interact) {
+    if (isset(RCS) && interact && !subsh) {
 	if (!nohistsave) {
 	    int writeflags = HFILE_USE_OPTIONS;
 	    if (from_where == ZEXIT_SIGNAL)
@@ -6075,7 +6075,7 @@ zexit(int val, enum zexit_t from_where)
 	    saveandpophiststack(1, writeflags);
 	    savehistfile(NULL, 1, writeflags);
 	}
-	if (islogin && !subsh) {
+	if (islogin) {
 	    sourcehome(".zlogout");
 #ifdef GLOBAL_ZLOGOUT
 	    if (isset(RCS) && isset(GLOBALRCS))