From ff6b6dd204838ece4570dbbcc45ee4eec1575a1c Mon Sep 17 00:00:00 2001
From: Lukas Eder <lukas.eder@gmail.com>
Date: Wed, 16 Oct 2019 11:14:12 +0200
Subject: [PATCH] [jOOQ/jOOQ#8528] Cascade drop column commands to local
 constraints

---
 .../java/org/jooq/impl/DDLInterpreter.java    | 45 +++++++++++++++++--
 jOOQ/src/main/java/org/jooq/impl/Tools.java   | 11 +++++
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/jOOQ/src/main/java/org/jooq/impl/DDLInterpreter.java b/jOOQ/src/main/java/org/jooq/impl/DDLInterpreter.java
index de7053e477..cb537a8c72 100644
--- a/jOOQ/src/main/java/org/jooq/impl/DDLInterpreter.java
+++ b/jOOQ/src/main/java/org/jooq/impl/DDLInterpreter.java
@@ -43,6 +43,7 @@ import static org.jooq.impl.ConstraintType.PRIMARY_KEY;
 import static org.jooq.impl.DSL.unquotedName;
 import static org.jooq.impl.SQLDataType.BIGINT;
 import static org.jooq.impl.Tools.EMPTY_FIELD;
+import static org.jooq.impl.Tools.intersect;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -268,6 +269,46 @@ final class DDLInterpreter {
         ));
     }
 
+    private final void dropColumns(MutableTable table, List<MutableField> fields) {
+        Iterator<MutableIndex> it1 = table.indexes.iterator();
+
+        indexLoop:
+        while (it1.hasNext()) {
+            for (MutableSortField msf : it1.next().fields) {
+                if (fields.contains(msf.field)) {
+                    it1.remove();
+                    continue indexLoop;
+                }
+            }
+        }
+
+        if (table.primaryKey != null)
+            if (intersect(table.primaryKey.keyFields, fields))
+                table.primaryKey = null;
+
+        Iterator<MutableUniqueKey> it2 = table.uniqueKeys.iterator();
+
+        ukLoop:
+        while (it2.hasNext()) {
+            if (intersect(it2.next().keyFields, fields)) {
+                it2.remove();
+                continue ukLoop;
+            }
+        }
+
+        Iterator<MutableForeignKey> it3 = table.foreignkeys.iterator();
+
+        fkLoop:
+        while (it3.hasNext()) {
+            if (intersect(it3.next().keyFields, fields)) {
+                it3.remove();
+                continue fkLoop;
+            }
+        }
+
+        table.fields.removeAll(fields);
+    }
+
     @SuppressWarnings({ "rawtypes", "unchecked" })
     private final void accept0(AlterTableImpl query) {
         Table<?> table = query.$table();
@@ -377,14 +418,12 @@ final class DDLInterpreter {
                 mk.name = (UnqualifiedName) renameConstraintTo.getUnqualifiedName();
         }
         else if (dropColumns != null) {
-            // TODO Implement cascade
-            // TODO check if any constraints or indexes reference this column.
             List<MutableField> fields = existing.fields(dropColumns.toArray(EMPTY_FIELD), false);
 
             if (fields.size() < dropColumns.size() && !query.$ifExistsColumn())
                 existing.fields(dropColumns.toArray(EMPTY_FIELD), true);
 
-            existing.fields.removeAll(fields);
+            dropColumns(existing, fields);
         }
         else if (dropConstraint != null) {
             ConstraintImpl impl = (ConstraintImpl) dropConstraint;
diff --git a/jOOQ/src/main/java/org/jooq/impl/Tools.java b/jOOQ/src/main/java/org/jooq/impl/Tools.java
index a43bf1619d..d88b5b4873 100644
--- a/jOOQ/src/main/java/org/jooq/impl/Tools.java
+++ b/jOOQ/src/main/java/org/jooq/impl/Tools.java
@@ -5282,4 +5282,15 @@ final class Tools {
         }
         return sb.toString();
     }
+
+    /**
+     * Whether the intersection of two collection is non-empty.
+     */
+    static final <T> boolean intersect(Collection<T> c1, Collection<T> c2) {
+        for (T t1 : c1)
+            if (c2.contains(t1))
+                return true;
+
+        return false;
+    }
 }