Allow to use non-primary columns in crossref tables

src/Propel/Generator/Model/CrossForeignKeys.php

@@ -132,7 +132,7 @@ public function getIncomingForeignKey(): ?ForeignKey
      */
     public function isAtLeastOneLocalPrimaryKeyNotCovered(ForeignKey $fk): bool
     {
-        $primaryKeys = $fk->getLocalPrimaryKeys();
+        $primaryKeys = $fk->getLocalColumnObjects();
         foreach ($primaryKeys as $primaryKey) {
             $covered = false;
             foreach ($this->getCrossForeignKeys() as $crossFK) {

src/Propel/Generator/Model/ForeignKey.php

@@ -874,7 +874,7 @@ public function isAtLeastOneLocalColumnRequired(): bool
      */
     public function isAtLeastOneLocalPrimaryKeyIsRequired(): bool
     {
-        foreach ($this->getLocalPrimaryKeys() as $pk) {
+        foreach ($this->getLocalColumnObjects() as $pk) {
             if ($pk->isNotNull() && !$pk->hasDefaultValue()) {
                 return true;
             }

tests/Propel/Tests/Issues/IssueIsCrossRefTest.php

@@ -0,0 +1,98 @@
+<?php
+
+/**
+ * MIT License. This file is part of the Propel package.
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Propel\Tests\Issues;
+
+use TestGroupObject;
+use TestUserObject;
+use TestGroupObjectNegative;
+use TestUserObjectNegative;
+use Propel\Generator\Util\QuickBuilder;
+use Propel\Tests\TestCase;
+
+/**
+ * Regression test for https://github.com/propelorm/Propel2/pull/1994
+ */
+class IssueIsCrossRefTest extends TestCase
+{
+    /**
+     * @return void
+     */
+    public function setUp(): void
+    {
+        if (!class_exists('\TestUserGroupObject')) {
+            $schema = <<<EOF
+<database>
+    <table name="test_group_object">
+        <column name="id" type="integer" primaryKey="true" required="true" />
+    </table>
+    <table name="test_user_object">
+        <column name="id" type="integer" primaryKey="true" required="true" />
+    </table>
+    <table name="test_group_object_negative">
+        <column name="id" type="integer" primaryKey="true" required="true" />
+    </table>
+    <table name="test_user_object_negative">
+        <column name="id" type="integer" primaryKey="true" required="true" />
+    </table>
+    <table name="test_user_group_object" isCrossRef="true">
+        <column name="id" type="integer" primaryKey="true" required="true" />
+        <column name="user_id" type="integer" required="true"/>
+        <column name="group_id" type="integer" required="true"/>
+        <foreign-key foreignTable="test_user_object">
+            <reference local="user_id" foreign="id"/>
+        </foreign-key>
+        <foreign-key foreignTable="test_group_object">
+            <reference local="group_id" foreign="id"/>
+        </foreign-key>
+    </table>
+    <table name="test_user_group_object_negative" isCrossRef="true">
+        <column name="id" type="integer" primaryKey="true" required="true" />
+        <column name="user_negative_id" type="integer"/>
+        <column name="group_negative_id" type="integer"/>
+        <foreign-key foreignTable="test_user_object_negative">
+            <reference local="user_negative_id" foreign="id"/>
+        </foreign-key>
+        <foreign-key foreignTable="test_group_object_negative">
+            <reference local="group_negative_id" foreign="id"/>
+        </foreign-key>
+    </table>
+</database>
+EOF;
+            QuickBuilder::buildSchema($schema);
+        }
+    }
+
+    /**
+     * @return void
+     */
+    public function testGenerateIsCrossRefCode()
+    {
+        $testGroupObject = new TestGroupObject();
+        $testUserObject = new TestUserObject();
+        $testGroupNegative = new TestGroupObjectNegative();
+        $testUserNegative = new TestUserObjectNegative();
+
+        $this->assertTrue(
+            method_exists($testGroupObject, 'createTestUserObjectsQuery'),
+            'Class does not have method createTestUserObjectsQuery'
+        );
+        $this->assertTrue(
+            method_exists($testUserObject, 'createTestGroupObjectsQuery'),
+            'Class does not have method createTestUserObjectsQuery'
+        );
+        $this->assertFalse(
+            method_exists($testGroupNegative, 'createTestUserObjectNegativesQuery'),
+            'Class does not have method createTestUserObjectsQuery'
+        );
+        $this->assertFalse(
+            method_exists($testUserNegative, 'createTestGroupObjectNegativesQuery'),
+            'Class does not have method createTestUserObjectsQuery'
+        );
+    }
+}