Reset the implementation of empty arrays.

2 files changed, 9 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index e713dd48..5efa7213 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2019-01-06         Andrew J. Schorr      <aschorr@telemetry-investments.com>
 
+	* array.c (do_delete): If the array is now empty, reset it to the
+	null implementation to avoid being locked into the backend
+	optimization previously selected.
+
+2019-01-06         Andrew J. Schorr      <aschorr@telemetry-investments.com>
+
 	Remove pointless alength macro/method that uses a needless
 	function call indirection to access the table_size value.
 
diff --git a/array.c b/array.c
index d8fbab33..a47660c8 100644
--- a/array.c
+++ b/array.c
@@ -608,6 +608,9 @@ do_delete(NODE *symbol, int nsubs)
 
 	(void) assoc_remove(symbol, subs);
 	DEREF(subs);
+	if (assoc_empty(symbol))
+		/* last element was removed, so reset array type to null */
+		null_array(symbol);
 
 #undef free_subs
 }