TableVal: Propagate &on_change attribute through copy()

Mostly for consistency with &default, &expire_func and other attributes
being propagated through a copy(). Seems this was just missed during
the implementation and/or was never tested for.

NEWS

@@ -20,6 +20,9 @@ Changed Functionality
   an appropriate callback function, log a warning and return a generic handle
   value based on the analyzer and connection information.
 
+- The ``&on_change`` attribute of set and tables is propagated through ``copy()``.
+
+
 Zeek 5.2.0
 ==========
 

src/Val.cc

@@ -2649,6 +2649,9 @@ ValPtr TableVal::DoClone(CloneState* state)
 		detail::timer_mgr->Add(tv->timer);
 		}
 
+	if ( change_func )
+		tv->change_func = change_func;
+
 	if ( expire_func )
 		tv->expire_func = expire_func;
 

testing/btest/Baseline/language.on_change-copy/output

@@ -0,0 +1,9 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+inserting
+tbl_change, a, 1, 5, TABLE_ELEMENT_NEW
+set_change, hi, TABLE_ELEMENT_NEW
+changing
+tbl_change, a, 1, 5, TABLE_ELEMENT_CHANGED
+deleting
+tbl_change, a, 1, 2, TABLE_ELEMENT_REMOVED
+set_change, hi, TABLE_ELEMENT_REMOVED

testing/btest/language/on_change-copy.test

@@ -0,0 +1,31 @@
+# @TEST-EXEC: zeek -b %INPUT >output
+# @TEST-EXEC: btest-diff output
+
+module TestModule;
+
+function tbl_change(t: table[string, int] of count, tpe: TableChange, idxa: string, idxb: int, val: count)
+	{
+	print "tbl_change", idxa, idxb, val, tpe;
+	}
+
+function set_change(t: set[string], tpe: TableChange, idx: string)
+	{
+	print "set_change", idx, tpe;
+	}
+
+global t: table[string, int] of count &on_change=tbl_change;
+global s: set[string] &on_change=set_change;
+
+event zeek_init()
+	{
+	local tc = copy(t);
+	local sc = copy(s);
+	print "inserting";
+	tc["a", 1] = 5;
+	add sc["hi"];
+	print "changing";
+	tc["a", 1] = 2;
+	print "deleting";
+	delete tc["a", 1];
+	delete sc["hi"];
+	}