From 74e79e6330c01f027ac6f772a7ceefdc807416ed Mon Sep 17 00:00:00 2001
From: freestrings <freestrings@gmail.com>
Date: Sat, 21 Mar 2020 15:50:19 +0900
Subject: [PATCH] Empty result for filter expression returns array of null #39

---
 src/select/mod.rs    |  8 ++++----
 tests/op.rs          | 28 +++++++++++++---------------
 tests/return_type.rs | 15 ++++++++++++---
 3 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/src/select/mod.rs b/src/select/mod.rs
index ac639ea..cf5c312 100644
--- a/src/select/mod.rs
+++ b/src/select/mod.rs
@@ -220,7 +220,7 @@ impl<'a> FilterTerms<'a> {
 
             if tmp.is_empty() {
                 self.0.pop();
-                return Some(vec![&Value::Null]);
+                return Some(vec![]);
             } else {
                 return Some(tmp);
             }
@@ -275,7 +275,7 @@ impl<'a> FilterTerms<'a> {
 
             if tmp.is_empty() {
                 self.0.pop();
-                return Some(vec![&Value::Null]);
+                return Some(vec![]);
             } else {
                 return Some(tmp);
             }
@@ -530,7 +530,7 @@ impl<'a, 'b> Selector<'a, 'b> {
                 }
                 ExprTerm::Json(rel, _, v) => {
                     if v.is_empty() {
-                        self.current = Some(vec![&Value::Null]);
+                        self.current = Some(vec![]);
                     } else if let Some(vec) = rel {
                         self.current = Some(vec);
                     } else {
@@ -538,7 +538,7 @@ impl<'a, 'b> Selector<'a, 'b> {
                     }
                 }
                 ExprTerm::Bool(false) => {
-                    self.current = Some(vec![&Value::Null]);
+                    self.current = Some(vec![]);
                 }
                 _ => {}
             }
diff --git a/tests/op.rs b/tests/op.rs
index 1146ac0..1ade0dd 100644
--- a/tests/op.rs
+++ b/tests/op.rs
@@ -1,8 +1,6 @@
 #[macro_use]
 extern crate serde_json;
 
-use serde_json::Value;
-
 use common::{read_json, select_and_then_compare, setup};
 
 mod common;
@@ -58,7 +56,7 @@ fn op_object_and_or() {
     select_and_then_compare(
         "$.friends[?( (@.id >= 2 || @.id == 1) && @.id == 0)]",
         read_json("./benchmark/data_obj.json"),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -202,7 +200,7 @@ fn op_lt_for_string_value() {
     setup();
 
     select_and_then_compare(
-        r#"$.[?(@.a < "b")]"#, json!({ "a": "b" }), json!([Value::Null]),
+        r#"$.[?(@.a < "b")]"#, json!({ "a": "b" }), json!([]),
     );
 }
 
@@ -220,7 +218,7 @@ fn op_gt_for_string_value() {
     setup();
 
     select_and_then_compare(
-        r#"$.[?(@.a > "b")]"#, json!({ "a": "b" }), json!([Value::Null]),
+        r#"$.[?(@.a > "b")]"#, json!({ "a": "b" }), json!([]),
     );
 }
 
@@ -251,7 +249,7 @@ fn op_ne_for_object_value() {
     select_and_then_compare(
         r#"$.[?(@.a != @.c)]"#,
         json!({"a": { "1": 1 }, "b": { "2": 2 }, "c": { "1": 1 }}),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -262,7 +260,7 @@ fn op_lt_for_object_value() {
     select_and_then_compare(
         r#"$.[?(@.a < @.c)]"#,
         json!({"a": { "1": 1 }, "b": { "2": 2 }, "c": { "1": 1 }}),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -273,7 +271,7 @@ fn op_le_for_object_value() {
     select_and_then_compare(
         r#"$.[?(@.a <= @.c)]"#,
         json!({"a": { "1": 1 }, "b": { "2": 2 }, "c": { "1": 1 }}),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -284,7 +282,7 @@ fn op_gt_for_object_value() {
     select_and_then_compare(
         r#"$.[?(@.a > @.c)]"#,
         json!({"a": { "1": 1 }, "b": { "2": 2 }, "c": { "1": 1 }}),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -295,7 +293,7 @@ fn op_ge_for_object_value() {
     select_and_then_compare(
         r#"$.[?(@.a >= @.c)]"#,
         json!({"a": { "1": 1 }, "b": { "2": 2 }, "c": { "1": 1 }}),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -306,7 +304,7 @@ fn op_eq_for_complex_value() {
     select_and_then_compare(
         r#"$.[?(1 == @.a)]"#,
         json!({ "a": { "b": 1 } }),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -317,7 +315,7 @@ fn op_ne_for_complex_value() {
     select_and_then_compare(
         r#"$.[?("1" != @.a)]"#,
         json!({ "a": { "b": 1 } }),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -328,7 +326,7 @@ fn op_le_for_complex_value() {
     select_and_then_compare(
         r#"$.[?(@.a <= 1)]"#,
         json!({ "a": { "b": 1 } }),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -339,7 +337,7 @@ fn op_gt_for_complex_value() {
     select_and_then_compare(
         r#"$.[?(@.a > "1")]"#,
         json!({ "a": { "b": 1 } }),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -355,7 +353,7 @@ fn op_compare_different_types() {
     ]
         .iter()
     {
-        select_and_then_compare(path, json!({}), json!([Value::Null]));
+        select_and_then_compare(path, json!({}), json!([]));
     }
 }
 
diff --git a/tests/return_type.rs b/tests/return_type.rs
index 04a5fed..0139dda 100644
--- a/tests/return_type.rs
+++ b/tests/return_type.rs
@@ -1,8 +1,6 @@
 #[macro_use]
 extern crate serde_json;
 
-use serde_json::Value;
-
 use common::{read_json, select_and_then_compare, setup};
 
 mod common;
@@ -62,7 +60,7 @@ fn return_type_for_child_object_not_matched() {
     select_and_then_compare(
         "$.school[?(@.friends[10])]",
         read_json("./benchmark/data_obj.json"),
-        json!([Value::Null]),
+        json!([]),
     );
 }
 
@@ -96,4 +94,15 @@ fn return_type_for_array_filter_true() {
             {"id": 2, "name": "Gray Berry"}
         ]]),
     );
+}
+
+#[test]
+fn return_type_empty() {
+    setup();
+
+    select_and_then_compare(
+        "$[?(@.key==43)]",
+        json!([{"key": 42}]),
+        json!([]),
+    );
 }
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