#2328 - Postgres JSONB dirty checking - trim json

ebean-core/src/main/java/io/ebeaninternal/server/type/JsonTrim.java

@@ -0,0 +1,33 @@
+package io.ebeaninternal.server.type;
+
+/**
+ * Helper that removes whitespace from JSON. Used to normalise Postgres JSONB content.
+ */
+final class JsonTrim {
+
+  /**
+   * Return JSON with whitespace trimmed.
+   */
+  static String trim(String json) {
+    if (json == null) {
+      return null;
+    }
+    int len = json.length();
+    StringBuilder builder = new StringBuilder(len);
+    boolean escaped = false;
+    boolean quoted = false;
+    for (int i = 0; i < len; i++) {
+      char c = json.charAt(i);
+      if (c == '\"') {
+        if (!escaped) quoted = !quoted;
+        else escaped = false;
+      } else if (quoted && c == '\\') {
+        escaped = true;
+      }
+      if (quoted || !Character.isWhitespace(c)) {
+        builder.append(c);
+      }
+    }
+    return builder.toString();
+  }
+}

ebean-core/src/main/java/io/ebeaninternal/server/type/ScalarTypeJsonObjectMapper.java

@@ -39,7 +39,11 @@ final class ScalarTypeJsonObjectMapper {
       return new GenericObject(jsonManager, field, dbType, docType);
     }
     // using the global default MutationDetection mode (defaults to HASH)
-    prop.setMutationDetection(jsonManager.mutationDetection());
+    final MutationDetection defaultMode = jsonManager.mutationDetection();
+    prop.setMutationDetection(defaultMode);
+    if (MutationDetection.NONE == defaultMode) {
+      return new NoMutationDetection(jsonManager, field, dbType, docType);
+    }
     return new GenericObject(jsonManager, field, dbType, docType);
   }
 
@@ -68,8 +72,11 @@ final class ScalarTypeJsonObjectMapper {
    */
   private static final class GenericObject extends Base<Object> {
 
+    private final boolean jsonb;
+
     GenericObject(TypeJsonManager jsonManager, AnnotatedField field, int dbType, DocPropertyType docType) {
       super(Object.class, jsonManager, field, dbType, docType);
+      this.jsonb = "jsonb".equals(pgType);
     }
 
     @Override
@@ -80,6 +87,9 @@ final class ScalarTypeJsonObjectMapper {
     @Override
     public Object read(DataReader reader) throws SQLException {
       String json = reader.getString();
+      if (jsonb) {
+        json = JsonTrim.trim(json);
+      }
       // pushJson such that we MD5 and store on EntityBeanIntercept later
       reader.pushJson(json);
       if (json == null || json.isEmpty()) {

ebean-core/src/test/java/io/ebeaninternal/server/type/JsonTrimTest.java

@@ -0,0 +1,21 @@
+package io.ebeaninternal.server.type;
+
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class JsonTrimTest {
+
+  @Test
+  public void trim_array() {
+    final String trimmed = JsonTrim.trim("[{\"name\": \"one\", \"along\": 1, \"timestamp\": 1629609021559}, {\"name\": \"two\", \"along\": 2, \"timestamp\": 1629609021559}]");
+    assertThat(trimmed).isEqualTo("[{\"name\":\"one\",\"along\":1,\"timestamp\":1629609021559},{\"name\":\"two\",\"along\":2,\"timestamp\":1629609021559}]");
+  }
+
+  @Test
+  public void trim_object() {
+    final String trimmed = JsonTrim.trim("{\"name\":  \"one\",\t \t \"along\": 1, \"timestamp\": 1629609021559}");
+    assertThat(trimmed).isEqualTo("{\"name\":\"one\",\"along\":1,\"timestamp\":1629609021559}");
+  }
+}