Introduce ObjectMapperValueToTree refaster rule

Author: mohamedsamehsalah

error-prone-contrib/pom.xml

@@ -47,6 +47,10 @@
             <artifactId>jackson-annotations</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-core</artifactId>
+        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/JacksonRules.java

@@ -1,6 +1,8 @@
 package tech.picnic.errorprone.refasterrules;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -45,4 +47,17 @@ Optional<JsonNode> after(JsonNode node, String fieldName) {
       return node.optional(fieldName);
     }
   }
+
+  /** Prefer {@link ObjectMapper#valueToTree(Object)} over more contrived alternatives. */
+  static final class ObjectMapperValueToTree {
+    @BeforeTemplate
+    JsonNode before(ObjectMapper objectMapper, Object object) throws JsonProcessingException {
+      return objectMapper.readTree(objectMapper.writeValueAsString(object));
+    }
+
+    @AfterTemplate
+    JsonNode after(ObjectMapper objectMapper, Object object) {
+      return objectMapper.valueToTree(object);
+    }
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/JacksonRulesTestInput.java

@@ -1,6 +1,8 @@
 package tech.picnic.errorprone.refasterrules;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.NullNode;
 import com.google.common.collect.ImmutableSet;
 import java.util.Optional;
@@ -22,4 +24,8 @@ ImmutableSet<Optional<JsonNode>> testJsonNodeOptionalString() {
         Optional.of(NullNode.getInstance().get("baz")),
         Optional.ofNullable(NullNode.getInstance().get("qux")));
   }
+
+  JsonNode testObjectMapperValueToTree() throws JsonProcessingException {
+    return new ObjectMapper().readTree(new ObjectMapper().writeValueAsString("foo"));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/JacksonRulesTestOutput.java

@@ -1,6 +1,8 @@
 package tech.picnic.errorprone.refasterrules;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.NullNode;
 import com.google.common.collect.ImmutableSet;
 import java.util.Optional;
@@ -22,4 +24,8 @@ ImmutableSet<Optional<JsonNode>> testJsonNodeOptionalString() {
         NullNode.getInstance().optional("baz"),
         NullNode.getInstance().optional("qux"));
   }
+
+  JsonNode testObjectMapperValueToTree() throws JsonProcessingException {
+    return new ObjectMapper().valueToTree("foo");
+  }
 }