Fixed FasterXML#2755

sp4ce · Jun 12, 2020 · 97ed5c9 · 97ed5c9
1 parent cc1dd92
commit 97ed5c9
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Showing 4 changed files with 36 additions and 4 deletions.
diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
@@ -8,6 +8,9 @@ Project: jackson-databind
 
 #2486: Builder Deserialization with JsonCreator Value vs Array
  (reported by Ville K)
+#2755: `StdSubtypeResolver` is not thread safe (possibly due to copy
+  not being made with `ObjectMapper.copy()`)
+ (reported by tjwilson90@github)
 
 2.11.0 (26-Apr-2020)
 

diff --git a/src/main/java/com/fasterxml/jackson/databind/ObjectMapper.java b/src/main/java/com/fasterxml/jackson/databind/ObjectMapper.java
@@ -512,7 +512,7 @@ public boolean useForType(JavaType t)
      * (should very quickly converge to zero after startup), let's
      * explicitly define a low concurrency setting.
      *<p>
-     * Since version 1.5, these may are either "raw" deserializers (when
+     * These may are either "raw" deserializers (when
      * no type information is needed for base type), or type-wrapped
      * deserializers (if it is needed)
      */
@@ -559,7 +559,7 @@ protected ObjectMapper(ObjectMapper src)
     {
         _jsonFactory = src._jsonFactory.copy();
         _jsonFactory.setCodec(this);
-        _subtypeResolver = src._subtypeResolver;
+        _subtypeResolver = src._subtypeResolver.copy();
         _typeFactory = src._typeFactory;
         _injectableValues = src._injectableValues;
         _configOverrides = src._configOverrides.copy();

diff --git a/src/main/java/com/fasterxml/jackson/databind/jsontype/SubtypeResolver.java b/src/main/java/com/fasterxml/jackson/databind/jsontype/SubtypeResolver.java
@@ -14,9 +14,25 @@
  */
 public abstract class SubtypeResolver
 {
+    /**
+     * Method called by {@code ObjectMapper.copy()} to make sure that
+     * {@link SubtypeResolver} instances used by two independent mappers
+     * can not cause thread-safety issues: if resolver is immutable, it
+     * may return {@code this}, but if not, it should create a copy with
+     * same configuration and return that instead.
+     *
+     * @return Either new instance with same configuration as this one (if
+     *    instances are mutable), or this instance (if immutable)
+     *
+     * @since 2.12
+     */
+    public SubtypeResolver copy() {
+        return this;
+    }
+
     /*
     /**********************************************************
-    /* Methods for registering external subtype definitions
+    /* Methods for registering external subtype definitions (init/config)
     /**********************************************************
      */
 
@@ -36,7 +52,7 @@ public abstract class SubtypeResolver
 
     /*
     /**********************************************************
-    /* Subtype resolution
+    /* Subtype resolution (public API)
     /**********************************************************
      */
 

diff --git a/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdSubtypeResolver.java b/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdSubtypeResolver.java
@@ -23,6 +23,19 @@ public class StdSubtypeResolver
 
     public StdSubtypeResolver() { }
 
+    // @since 2.12
+    protected StdSubtypeResolver(StdSubtypeResolver src) {
+        LinkedHashSet<NamedType> reg = src._registeredSubtypes;
+        _registeredSubtypes = (reg == null) ? null
+                : new LinkedHashSet<>(reg);
+    }
+
+    // @since 2.12
+    @Override
+    public SubtypeResolver copy() {
+        return new StdSubtypeResolver(this);
+    }
+
     /*
     /**********************************************************
     /* Subtype registration