Fix RlistEqual comparison on lists of different lengths

The original issue that leads to this is the fact that the cache
for execresult and execresult_as_data were mixed. This is caused by two
separate issues:

* The function cache uses the args list as key and discards the function
  itself. This means different function with the same args are considered
  identical, and cache is reused.
* The args are passed as an Rlist, and the used Rlist comparison ignores the
  additional items of the longest list when comparing two lists of
  different lengths, leading to treating execresult and execresult_as_data
  as identical when using the same command and shell args.

This PR only fixes the specific case of execresult, but leaves other
function cache issues (e.g. host2ip vs. ip2host could be confused).

libpromises/rlist.c

@@ -1657,8 +1657,8 @@ bool RlistEqual(const Rlist *list1, const Rlist *list2)
             assert(rp1->val.item == NULL && rp2->val.item == NULL);
         }
     }
-
-    return true;
+    // return false if lengths are different
+    return (rp1 == NULL && rp2 == NULL);
 }
 
 bool RlistEqual_untyped(const void *list1, const void *list2)

tests/acceptance/01_vars/04_containers/execresult_and_as_data.cf

@@ -0,0 +1,41 @@
+#######################################################
+#
+# Test the ability to call the same command with execresult and execresult_as_data
+#
+#######################################################
+
+body common control
+{
+      inputs => { "../../default.cf.sub" };
+      bundlesequence  => { default("$(this.promise_filename)") };
+      version => "1.0";
+}
+
+#######################################################
+
+
+bundle agent init
+{
+}
+
+#######################################################
+
+bundle agent test
+{
+  vars:
+    !windows::
+     "res1" string => execresult("echo test", "useshell");
+     "res2" data   => execresult_as_data("echo test", "useshell", "stdout");
+    windows::
+     "res1" string => execresult("echo test", "powershell");
+     "res2" data   => execresult_as_data("echo test", "powershell", "stdout");
+}
+
+
+#######################################################
+
+bundle agent check
+{
+  methods:
+      "any" usebundle => dcs_check_strcmp("${test.res1}", "${test.res2[output]}", "$(this.promise_filename)", "no");
+}

tests/unit/rlist_test.c

@@ -31,6 +31,23 @@ static void test_length(void)
     RlistDestroy(list);
 }
 
+static void test_equality(void)
+{
+    Rlist *list1 = RlistFromSplitString("a,b,c", ',');
+    Rlist *list2 = RlistFromSplitString("a,b,c", ',');
+    Rlist *list3 = RlistFromSplitString("z,b,c", ',');
+    Rlist *list4 = RlistFromSplitString("a,b,c,d", ',');
+
+    assert_true(RlistEqual(list1, list2));
+    assert_false(RlistEqual(list1, list3));
+    assert_false(RlistEqual(list1, list4));
+
+    RlistDestroy(list1);
+    RlistDestroy(list2);
+    RlistDestroy(list3);
+    RlistDestroy(list4);
+}
+
 static void test_prepend_scalar_idempotent(void)
 {
     Rlist *list = NULL;
@@ -750,6 +767,7 @@ int main()
     {
         unit_test(test_prepend_scalar_idempotent),
         unit_test(test_length),
+        unit_test(test_equality),
         unit_test(test_copy),
         unit_test(test_rval_to_scalar),
         unit_test(test_rval_to_scalar2),