Fix Coercion fail message around Array and Object. (#3962)

Author: JooHyukKim

src/main/java/com/fasterxml/jackson/databind/deser/std/StdDeserializer.java

@@ -1421,7 +1421,7 @@ protected final String _parseString(JsonParser p, DeserializationContext ctxt,
             return ob.toString();
         // 29-Jun-2020, tatu: New! "Scalar from Object" (mostly for XML)
         case JsonTokenId.ID_START_OBJECT:
-            return ctxt.extractScalarFromObject(p, this, _valueClass);
+            return ctxt.extractScalarFromObject(p, this, rawTargetType);
         case JsonTokenId.ID_NUMBER_INT:
             act = _checkIntToStringCoercion(p, ctxt, rawTargetType);
             break;
@@ -1453,7 +1453,7 @@ protected final String _parseString(JsonParser p, DeserializationContext ctxt,
                 return text;
             }
         }
-        return (String) ctxt.handleUnexpectedToken(getValueType(ctxt), p);
+        return (String) ctxt.handleUnexpectedToken(rawTargetType, p);
     }
 
     /**

src/test/java/com/fasterxml/jackson/databind/convert/DisableCoercions3690Test.java

@@ -1,11 +1,14 @@
 package com.fasterxml.jackson.databind.convert;
 
-import java.util.List;
-
-import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.cfg.CoercionAction;
 import com.fasterxml.jackson.databind.cfg.CoercionInputShape;
 import com.fasterxml.jackson.databind.exc.InvalidFormatException;
+import com.fasterxml.jackson.databind.exc.MismatchedInputException;
+import com.fasterxml.jackson.databind.type.TypeFactory;
+import java.util.List;
 
 public class DisableCoercions3690Test extends BaseMapTest
 {
@@ -14,6 +17,18 @@ static class Input3690 {
         public List<String> field;
     }
 
+    static class Input3924<T> {
+        private T field;
+
+        public T getField() {
+            return field;
+        }
+
+        public void setField(T field) {
+            this.field = field;
+        }
+    }
+
     // [databind#3690]
     public void testCoercionFail3690() throws Exception
     {
@@ -38,4 +53,50 @@ public void testCoercionFail3690() throws Exception
             verifyException(e, "to `java.lang.String` value");
         }
     }
+
+    // [databind#3924]
+    public void testFailMessage3924() throws Exception {
+        // Arrange : Building a strict ObjectMapper.
+        ObjectMapper mapper = jsonMapperBuilder()
+                .withCoercionConfigDefaults(config -> {
+                    config.setCoercion(CoercionInputShape.Boolean, CoercionAction.Fail)
+                        .setCoercion(CoercionInputShape.Integer, CoercionAction.Fail)
+                        .setCoercion(CoercionInputShape.Float, CoercionAction.Fail)
+                        .setCoercion(CoercionInputShape.String, CoercionAction.Fail)
+                        .setCoercion(CoercionInputShape.Array, CoercionAction.Fail)
+                        .setCoercion(CoercionInputShape.Object, CoercionAction.Fail);
+                })
+                .build();
+
+        // Arrange : Type configuration 
+        TypeFactory typeFactory = mapper.getTypeFactory();
+        JavaType arrayType = typeFactory.constructParametricType(List.class, String.class);
+        JavaType inputType = typeFactory.constructParametricType(Input3924.class, arrayType);
+
+        // Act & Assert
+        _verifyFailedCoercionWithInvalidFormat("{ \"field\": [ 1 ] }", 
+                "Cannot coerce Integer value (1) to `java.lang.String` value",
+                mapper, inputType);
+        
+        _verifyFailedCoercionWithInvalidFormat("{ \"field\": [ [ 1 ] ] }", 
+                "Cannot deserialize value of type `java.lang.String` from Array value", 
+                mapper, inputType);
+        
+        _verifyFailedCoercionWithInvalidFormat("{ \"field\": [ { \"field\": 1 } ] }",
+                "Cannot deserialize value of type `java.lang.String` from Object value",
+                mapper, inputType);
+        
+    }
+
+    private void _verifyFailedCoercionWithInvalidFormat(String jsonStr, String expectedMsg, ObjectMapper mapper, 
+                                                        JavaType inputType) throws Exception 
+    {
+        try {
+            mapper.readValue(jsonStr, inputType);
+            fail("Should not pass");
+        } catch (MismatchedInputException e) {
+            assertEquals(String.class, e.getTargetType());
+            verifyException(e, expectedMsg);
+        }
+    }
 }