flyway#1154 - Drop functions with length attributes in DB2

flyway-core/src/main/java/org/flywaydb/core/internal/dbsupport/db2/DB2Function.java

@@ -1,12 +1,12 @@
 /**
  * Copyright 2010-2015 Boxfuse GmbH
- *
+ * <p>
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- *
- *         http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -22,33 +22,76 @@
 import org.flywaydb.core.internal.util.StringUtils;
 
 import java.sql.SQLException;
+import java.util.Arrays;
+import java.util.Collection;
 
 /**
  * Db2-specific function.
  */
 public class DB2Function extends Function {
-    /**
-     * Creates a new Db2 function.
-     *
-     * @param jdbcTemplate The Jdbc Template for communicating with the DB.
-     * @param dbSupport    The database-specific support.
-     * @param schema       The schema this function lives in.
-     * @param name         The name of the function.
-     * @param args         The arguments of the function.
-     */
-    public DB2Function(JdbcTemplate jdbcTemplate, DbSupport dbSupport, Schema schema, String name, String... args) {
-        super(jdbcTemplate, dbSupport, schema, name, args);
-    }
-
-    @Override
-    protected void doDrop() throws SQLException {
-        jdbcTemplate.execute("DROP FUNCTION "
-                + dbSupport.quote(schema.getName(), name)
-                + "(" + StringUtils.arrayToCommaDelimitedString(args) + ")");
-    }
-
-    @Override
-    public String toString() {
-        return super.toString() + "(" + StringUtils.arrayToCommaDelimitedString(args) + ")";
-    }
+
+	//Functions with Decfloat and Binary cannot be dropped with specified arguments, but may be dropped without arguments if their
+	//names are unique => This means that if you have overloaded functions with these types, the drop statements will fail.
+	// A possible workaround is to use unique names for functions with these types.
+	private static final Collection<String> typesWithLength = Arrays.asList(
+			"character",
+			"char",
+			"varchar",
+			"graphic",
+			"vargraphic",
+			"decimal",
+			"float",
+			"varbinary");
+
+	/**
+	 * Creates a new Db2 function.
+	 *
+	 * @param jdbcTemplate The Jdbc Template for communicating with the DB.
+	 * @param dbSupport    The database-specific support.
+	 * @param schema       The schema this function lives in.
+	 * @param name         The name of the function.
+	 * @param args         The arguments of the function.
+	 */
+	public DB2Function(JdbcTemplate jdbcTemplate, DbSupport dbSupport, Schema schema, String name, String... args) {
+		super(jdbcTemplate, dbSupport, schema, name, args);
+	}
+
+	@Override
+	protected void doDrop() throws SQLException {
+		try {
+			jdbcTemplate.execute("DROP FUNCTION "
+					+ dbSupport.quote(schema.getName(), name)
+					+ "(" + argsToCommaSeparatedString(args) + ")");
+		} catch (SQLException e) {
+			//Fallback - try to drop it without arguments - will catch most cases that are not supported above, including
+			//functions with types "decfloat(16)", "decfloat(34)" and "binary large object"
+			jdbcTemplate.execute("DROP FUNCTION " + dbSupport.quote(schema.getName(), name));
+		}
+	}
+
+	/**
+	 * Creates a comma separated string of the arguments, with special treatment of types that have or may have length. In that
+	 * case we need to add empty parenthesis to get a match.
+	 *
+	 * @param args The argument list
+	 * @return A comma separated string that can be included in the function drop statement
+	 */
+	private String argsToCommaSeparatedString(String[] args) {
+		StringBuilder buf = new StringBuilder();
+		for (String arg : args) {
+			if (buf.length() > 0) {
+				buf.append(",");
+			}
+			buf.append(arg);
+			if (typesWithLength.contains(arg.toLowerCase())) {
+				buf.append("()"); //Add parenthesis to match on "wildcard" length
+			}
+		}
+		return buf.toString();
+	}
+
+	@Override
+	public String toString() {
+		return super.toString() + "(" + StringUtils.arrayToCommaDelimitedString(args) + ")";
+	}
 }

flyway-core/src/test/resources/migration/dbsupport/db2/sql/function/V1__Function.sql

@@ -14,20 +14,70 @@
 -- limitations under the License.
 --
 
-CREATE FUNCTION TEST_FUNC ( PARAM1 INTEGER )
+CREATE FUNCTION TEST_FUNC(PARAM1 INTEGER)
   RETURNS INTEGER
-  LANGUAGE SQL
-RETURN
-1;
+LANGUAGE SQL
+  RETURN
+  1;
 
-CREATE FUNCTION TEST_FUNC ( PARAM1 INTEGER, PARAM2 INTEGER )
+CREATE FUNCTION TEST_FUNC(PARAM1 INTEGER, PARAM2 INTEGER)
   RETURNS INTEGER
-  LANGUAGE SQL
-RETURN
-1;
+LANGUAGE SQL
+  RETURN
+  1;
 
-CREATE FUNCTION TEST_FUNC ( PARAM1 INTEGER, PARAM2 INTEGER, PARAM3 INTEGER )
+CREATE FUNCTION TEST_FUNC(PARAM1 INTEGER, PARAM2 INTEGER, PARAM3 INTEGER)
   RETURNS INTEGER
-  LANGUAGE SQL
-RETURN
-1;
+LANGUAGE SQL
+  RETURN
+  1;
+
+CREATE OR REPLACE FUNCTION F_CHAR(ARG CHAR(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_VARCHAR(ARG VARCHAR(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_GRAPHIC(ARG GRAPHIC(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_VARGRAPHIC(ARG VARGRAPHIC(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_DECIMAL(ARG DECIMAL(3, 2))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_FLOAT(ARG FLOAT(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_DECFLOAT16(ARG DECFLOAT(16))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_DECFLOAT34(ARG DECFLOAT(34))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_BINARY(ARG BINARY LARGE OBJECT(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;
+
+CREATE OR REPLACE FUNCTION F_NVARCHAR(ARG NVARCHAR(3))
+  RETURNS INTEGER
+LANGUAGE SQL
+  RETURN 1;