Fix output fields order inconsistent with the input (#81)

jackson-jq/src/main/java/net/thisptr/jackson/jq/internal/misc/JsonNodeComparator.java

@@ -1,10 +1,9 @@
 package net.thisptr.jackson.jq.internal.misc;
 
 import java.io.Serializable;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
-import java.util.List;
+import java.util.Iterator;
 import java.util.Map;
 
 import com.fasterxml.jackson.databind.JsonNode;
@@ -92,30 +91,18 @@ public int compare(final JsonNode o1, final JsonNode o2) {
 		}
 
 		if (type == JsonNodeType.OBJECT) {
-			final List<String> names1 = Lists.newArrayList(o1.fieldNames());
-			final List<String> names2 = Lists.newArrayList(o2.fieldNames());
-
-			// compare by keys
-			Collections.sort(names1);
-			Collections.sort(names2);
-			final int s = Math.min(names1.size(), names2.size());
-			for (int i = 0; i < s; ++i) {
-				final int rr = names1.get(i).compareTo(names2.get(i));
-				if (rr != 0)
-					return rr;
+			if (o1.size() != o2.size()) {
+				return o1.size() - o2.size();
 			}
-			final int rr = Integer.compare(names1.size(), names2.size());
-			if (rr != 0)
-				return rr;
-
-			// compare by values (keys are sorted alphabetically)
-			for (final String name : names1) {
-				final int rrr = compare(o1.get(name), o2.get(name));
-				if (rrr != 0)
-					return rrr;
+			Iterator<Map.Entry<String, JsonNode>> it1 = o1.fields();
+			Iterator<Map.Entry<String, JsonNode>> it2 = o2.fields();
+			int rr = 0;
+			while (rr == 0 && it1.hasNext()) {
+				Map.Entry<String, JsonNode> entry1 = it1.next();
+				Map.Entry<String, JsonNode> entry2 = it2.next();
+				rr = entry1.getKey().compareTo(entry2.getKey()) | compare(entry1.getValue(), entry2.getValue());
 			}
-
-			return 0;
+			return rr;
 		}
 
 		throw new IllegalArgumentException("Unknown JsonNodeType: " + type);

jackson-jq/src/main/java/net/thisptr/jackson/jq/internal/tree/ObjectConstruction.java

@@ -1,7 +1,7 @@
 package net.thisptr.jackson.jq.internal.tree;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -26,7 +26,7 @@ public void add(final FieldConstruction field) {
 
 	@Override
 	public void apply(final Scope scope, final JsonNode in, final Path ipath, final PathOutput output, final boolean requirePath) throws JsonQueryException {
-		final Map<String, JsonNode> tmp = new HashMap<>();
+		final Map<String, JsonNode> tmp = new LinkedHashMap<>(fields.size());
 		applyRecursive(scope, in, output, fields, tmp);
 	}
 

jackson-jq/src/test/java/net/thisptr/jackson/jq/JsonQueryTest.java

@@ -13,6 +13,8 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Stream;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import net.thisptr.jackson.jq.internal.misc.JsonNodeComparator;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -132,10 +134,6 @@ static Stream<String> defaultTestCases() throws Throwable {
 		});
 	}
 
-	private static List<ComparableJsonNode> wrap(final List<JsonNode> values) {
-		return ComparableJsonNode.wrap(values);
-	}
-
 	private static Map<Version, Boolean> hasJqCache = new ConcurrentHashMap<>();
 	private static Evaluator cachedJqEvaluator;
 
@@ -162,15 +160,15 @@ private void test(final TestCase tc, final Version version) throws Throwable {
 		if (!tc.ignoreTrueJqBehavior && hasJqCache.computeIfAbsent(version, v -> TrueJqEvaluator.hasJq(v))) {
 			final Result result = cachedJqEvaluator.evaluate(tc.q, tc.in, version, 2000L);
 			assumeThat(result.error).as("%s", command).isNull();
-			assumeThat(wrap(tc.out)).as("%s", command).isEqualTo(wrap(result.values));
+			assertEquals(tc.out, result.values, "%s", command);
 		}
 
 		boolean failed = false;
 		try {
 			final JsonQuery q = JsonQuery.compile(tc.q, version);
 			final List<JsonNode> out = new ArrayList<>();
 			q.apply(scope, tc.in, out::add);
-			assertThat(wrap(out)).as("%s", command).isEqualTo(wrap(tc.out));
+			assertEquals(tc.out, out, "%s", command);
 
 			// JsonQuery.compile($.toString()).toString() === $.toString()
 			final String s1 = q.toString();
@@ -181,7 +179,7 @@ private void test(final TestCase tc, final Version version) throws Throwable {
 			final JsonQuery q1 = JsonQuery.compile(s1, version);
 			final List<JsonNode> out1 = new ArrayList<>();
 			q1.apply(scope, tc.in, out1::add);
-			assertThat(wrap(out1)).as("bad tostring: %s", command).isEqualTo(wrap(tc.out));
+			assertEquals(tc.out, out1, "bad tostring: %s", command);
 		} catch (final Throwable e) {
 			failed = true;
 			if (!tc.failing) {
@@ -196,6 +194,21 @@ private void test(final TestCase tc, final Version version) throws Throwable {
 			assertThat(failed).describedAs("unexpectedly succeeded").isTrue();
 	}
 
+	private void assertEquals(List<JsonNode> expected, List<JsonNode> actual, String description, Object... args) {
+		assertThat(actual).as(description, args)
+				.usingComparator((o1List, o2List) -> {
+					int s1 = o1List != null ? o1List.size() : -1;
+					int s2 = o2List != null ? o2List.size() : -1;
+					if (s1 != s2 || s1 == -1) return s1 - s2;
+					int r = 0;
+					for (int i = 0; i < s1 && r == 0; i++) {
+						r = JsonNodeComparator.getInstance().compare(o1List.get(i), o2List.get(i));
+					}
+					return r;
+				})
+				.isEqualTo(expected);
+	}
+
 	@ParameterizedTest
 	@MethodSource("defaultTestCases")
 	public void test(final String tcText) throws Throwable {

jackson-jq/src/test/resources/jq-test-extra-ok.json

@@ -484,7 +484,7 @@
 		"q": ".num_entries[\"1\"] = 10",
 		"in": {"num_entries": {"2": 20}},
 		"out": [
-			{"num_entries": {"1": 10, "2": 20}}
+			{"num_entries": {"2": 20, "1": 10}}
 		]
 	},
 	{
@@ -1036,5 +1036,19 @@
 			[20, 30],
 			[20, 40]
 		]
+	},
+	{
+		"q": "{a: {depth: 1, b: {depth: 2}}}",
+		"in": null,
+		"out": [
+			{
+				"a": {
+					"depth": 1,
+					"b": {
+						"depth": 2
+					}
+				}
+			}
+		]
 	}
 ]

jackson-jq/src/test/resources/tests/jq-1.5.yaml

@@ -844,7 +844,7 @@
 - q: '.foo = .bar'
   in: {"bar": 42}
   out:
-  - {"foo": 42, "bar": 42}
+  - {"bar": 42, "foo": 42}
   v: '[1.5, 1.5]'
 - q: '.foo |= .+1'
   in: {"foo": 42}

jackson-jq/src/test/resources/tests/jq-1.6.yaml

@@ -1047,7 +1047,7 @@
 - q: '.foo = .bar'
   in: {"bar": 42}
   out:
-  - {"foo": 42, "bar": 42}
+  - {"bar": 42, "foo": 42}
   v: '[1.6, 1.6]'
 - q: '.foo |= .+1'
   in: {"foo": 42}