Merge pull request apache#611 from Jugen/fix-clob-empty-string-compar…

…ison CAY-2850 Query using Clob comparison with empty String fails
swarmbox · Apr 23, 2024 · 064dc2a · 064dc2a
2 parents e0a5d09 + 9143de9
commit 064dc2a
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Showing 5 changed files with 17 additions and 4 deletions.
diff --git a/RELEASE-NOTES.txt b/RELEASE-NOTES.txt
@@ -100,4 +100,5 @@ CAY-2827 Saved data-source XML data doesn't correspond to the XSD schema
 CAY-2838 Vertical Inheritance: Problem setting db attribute to null via flattened path
 CAY-2840 Vertical Inheritance: Missing subclass attributes with joint prefetch
 CAY-2841 Multi column ColumnSelect with SHARED_CACHE fails after 1st select
-CAY-2844 Joint prefetch doesn't use ObjEntity qualifier
+CAY-2844 Joint prefetch doesn't use ObjEntity qualifier
+CAY-2850 Query using Clob comparison with empty String fails
diff --git a/cayenne/src/main/java/org/apache/cayenne/access/sqlbuilder/sqltree/TrimmingColumnNode.java b/cayenne/src/main/java/org/apache/cayenne/access/sqlbuilder/sqltree/TrimmingColumnNode.java
@@ -144,7 +144,8 @@ protected int getColumnSize() {
             }
             if(sibling.getType() == NodeType.VALUE) {
                 if(((ValueNode)sibling).getValue() instanceof CharSequence) {
-                    return ((CharSequence) ((ValueNode)sibling).getValue()).length();
+                    int valLen = ((CharSequence) ((ValueNode)sibling).getValue()).length();
+                    return Math.max(1, valLen);
                 }
             }
         }

diff --git a/cayenne/src/main/java/org/apache/cayenne/dba/derby/sqltree/DerbyValueNode.java b/cayenne/src/main/java/org/apache/cayenne/dba/derby/sqltree/DerbyValueNode.java
@@ -37,7 +37,7 @@ public DerbyValueNode(Object value, boolean isArray, DbAttribute attribute, bool
 
     protected void appendStringValue(QuotingAppendable buffer, CharSequence value) {
         if(getAttribute() == null || (getAttribute() != null && getAttribute().getType() == Types.CLOB)) {
-            buffer.append(" CAST(? AS VARCHAR(").append(value.length()).append("))");
+            buffer.append(" CAST(? AS VARCHAR(").append(Math.max(1,value.length())).append("))");
         } else {
             buffer.append(" ?");
         }

diff --git a/cayenne/src/main/java/org/apache/cayenne/dba/firebird/FirebirdSQLTreeProcessor.java b/cayenne/src/main/java/org/apache/cayenne/dba/firebird/FirebirdSQLTreeProcessor.java
@@ -54,7 +54,7 @@ protected void onValueNode(Node parent, ValueNode child, int index) {
             protected void appendStringValue(QuotingAppendable buffer, CharSequence value) {
                 buffer.append("CAST(");
                 super.appendStringValue(buffer, value);
-                buffer.append(" AS VARCHAR(").append(value.length()).append("))");
+                buffer.append(" AS VARCHAR(").append(Math.max(1,value.length())).append("))");
             }
         });
     }

diff --git a/cayenne/src/test/java/org/apache/cayenne/query/SelectQueryClobIT.java b/cayenne/src/test/java/org/apache/cayenne/query/SelectQueryClobIT.java
@@ -109,4 +109,15 @@ public void testSelectNotEqualsClob() throws Exception {
             assertEquals(1, objects.size());
         }
     }
+
+    @Test
+    public void testSelectNotEqualsEmptyClob() throws Exception {
+        if (accessStackAdapter.supportsLobComparisons()) {
+            createClobDataSet();
+            List<?> objects = ObjectSelect.query(ClobTestEntity.class)
+                    .where(ClobTestEntity.CLOB_COL.ne(""))
+                    .select(context);
+            assertEquals(2, objects.size());
+        }
+    }
 }