jinja : fix undefined keys and attributes and int/float as bool (#18924)

* fix undefined keys and attributes

* add falsy tests

* as_bool for integers and floats

* more falsy/truthy tests

* --typo

tests/test-jinja.cpp

@@ -191,6 +191,84 @@ static void test_conditionals(testing & t) {
         json::object(),
         "yes"
     );
+
+    test_template(t, "is undefined falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is undefined attribute falsy",
+        "{{ 'yes' if not y.x else 'no' }}",
+        {{"y", true}},
+        "yes"
+    );
+
+    test_template(t, "is undefined key falsy",
+        "{{ 'yes' if not y['x'] else 'no' }}",
+        {{"y", {{}}}},
+        "yes"
+    );
+
+    test_template(t, "is empty array falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", json::array()}},
+        "yes"
+    );
+
+    test_template(t, "is empty object falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", json::object()}},
+        "yes"
+    );
+
+    test_template(t, "is empty string falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", ""}},
+        "yes"
+    );
+
+    test_template(t, "is 0 falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", 0}},
+        "yes"
+    );
+
+    test_template(t, "is 0.0 falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", 0.0}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty array truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", json::array({""})}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty object truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", {"x", false}}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty string truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", "0"}},
+        "yes"
+    );
+
+    test_template(t, "is 1 truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", 1}},
+        "yes"
+    );
+
+    test_template(t, "is 1.0 truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", 1.0}},
+        "yes"
+    );
 }
 
 static void test_loops(testing & t) {