Minor fix to CollectionDeserializer to fix FasterXML/jackson-dataformats-text#199

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -8,6 +8,7 @@ Project: jackson-databind
 
 #2486: Builder Deserialization with JsonCreator Value vs Array
  (reported by Ville K)
+- Minor fix to `CollectionDeserializer` to help with [dataformats-text#199] (CSV)
 
 2.11.0 (26-Apr-2020)
 

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

@@ -236,9 +236,13 @@ public Collection<Object> deserialize(JsonParser p, DeserializationContext ctxt)
         // there is also possibility of "auto-wrapping" of single-element arrays.
         // Hence we only accept empty String here.
         if (p.hasToken(JsonToken.VALUE_STRING)) {
-            String str = p.getText();
-            if (str.length() == 0) {
-                return (Collection<Object>) _valueInstantiator.createFromString(ctxt, str);
+            // 16-May-2020, tatu: As [dataformats-text#199] need to avoid blocking
+            //    check to `isExpectedStartArrayToken()` (needed for CSV in-field array/list logic)
+            if (_valueInstantiator.canCreateFromString()) {
+                String str = p.getText();
+                if (str.length() == 0) {
+                    return (Collection<Object>) _valueInstantiator.createFromString(ctxt, str);
+                }
             }
         }
         return deserialize(p, ctxt, createDefaultInstance(ctxt));

src/test/java/com/fasterxml/jackson/databind/deser/jdk/JDKScalarsTest.java

@@ -564,7 +564,7 @@ private void _testEmptyToNullCoercion(Class<?> primType, Object emptyValue) thro
     public void testBase64Variants() throws Exception
     {
         final byte[] INPUT = "abcdefghijklmnopqrstuvwxyz1234567890abcdefghijklmnopqrstuvwxyz1234567890X".getBytes("UTF-8");
-        
+
         // default encoding is "MIME, no linefeeds", so:
         Assert.assertArrayEquals(INPUT, MAPPER.readValue(
                 quote("YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXoxMjM0NTY3ODkwYWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXoxMjM0NTY3ODkwWA=="),
@@ -585,7 +585,7 @@ public void testBase64Variants() throws Exception
         Assert.assertArrayEquals(INPUT, (byte[]) reader.with(Base64Variants.PEM).readValue(
                 quote("YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXoxMjM0NTY3ODkwYWJjZGVmZ2hpamts\\nbW5vcHFyc3R1dnd4eXoxMjM0NTY3ODkwWA=="
         )));
-    }    
+    }
 
     /*
     /**********************************************************