hush: fix EXIT trap display inside exit trap handler

function                                             old     new   delta
hush_exit                                             84      78      -6

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

shell/hush.c

@@ -1357,10 +1357,10 @@ static void hush_exit(int exitcode)
 		/* argv[0] is unused */
 		argv[1] = G.traps[0];
 		argv[2] = NULL;
-		G.traps[0] = NULL;
-		G.exiting = 1;
+		G.exiting = 1; /* prevent EXIT trap recursion */
 		builtin_eval(argv);
-		/* free(argv[1]); - why bother */
+		/* Note: G.traps[0] is not cleared!
+		 * "trap" will still show it */
 	}
 
 #if ENABLE_HUSH_JOB
@@ -7864,7 +7864,7 @@ static int FAST_FUNC builtin_exit(char **argv)
 	 * exit
 	 # EEE (then bash exits)
 	 *
-	 * we can use G.exiting = -1 as indicator "last cmd was exit"
+	 * TODO: we can use G.exiting = -1 as indicator "last cmd was exit"
 	 */
 
 	/* note: EXIT trap is run by hush_exit */

shell/hush_test/hush-trap/exit.right

@@ -1,2 +1,12 @@
 cow
 moo
+Traps1:
+trap -- 'exitfunc' EXIT
+Traps2:
+trap -- 'echo Should not run' EXIT
+Check1: 42
+Traps1:
+trap -- 'exitfunc' EXIT
+Traps2:
+trap -- 'echo Should not run' EXIT
+Check2: 42

shell/hush_test/hush-trap/exit.tests

@@ -1,3 +1,34 @@
 "$THIS_SH" -c 'trap "echo cow" 0'
 "$THIS_SH" -c 'trap "echo moo" EXIT'
 "$THIS_SH" -c 'trap "echo no" 0; trap 0'
+
+(
+exitfunc() {
+        echo "Traps1:"
+        trap
+        # EXIT trap is disabled after it is triggered,
+        # it can not be "re-armed" like this:
+        trap "echo Should not run" EXIT
+        echo "Traps2:"
+        trap
+}
+trap 'exitfunc' EXIT
+exit 42
+)
+echo Check1: $?
+
+(
+exitfunc() {
+        echo "Traps1:"
+        trap
+        # EXIT trap is disabled after it is triggered,
+        # it can not be "re-armed" like this:
+        trap "echo Should not run" EXIT
+        echo "Traps2:"
+        trap
+        exit 42
+}
+trap 'exitfunc' EXIT
+exit 66
+)
+echo Check2: $?