ACP2E-1709: error during declarative schema whitelsit generation

Author: pradeep1819

app/code/Magento/Developer/Model/Setup/Declaration/Schema/WhitelistGenerator.php

@@ -138,7 +138,6 @@ private function persistModule(Schema $schema, string $moduleName)
         //We need to load whitelist file and update it with new revision of code.
         // phpcs:disable Magento2.Functions.DiscouragedFunction
         if (file_exists($whiteListFileName)) {
-            // phpcs:disable Magento2.Functions.DiscouragedFunction
             $content = json_decode(file_get_contents($whiteListFileName), true);
         }
 
@@ -203,46 +202,16 @@ private function getElementsWithAutogeneratedName(Schema $schema, string $tableN
             }
         }
 
-        $constraintName = $this->getConstraintName($schema, $tableName, $tableData);
-        if ($constraintName) {
-            $declaredStructure += $constraintName;
-        }
-
-        return $declaredStructure;
-    }
-
-    /**
-     * Provide autogenerated names of the table constraint.
-     *
-     * @param Schema $schema
-     * @param string $tableName
-     * @param array $tableData
-     * @return array
-     */
-    private function getConstraintName(Schema $schema, string $tableName, array $tableData): array
-    {
-        $declaredStructure = [];
-        $table = $schema->getTableByName($tableName);
-
         $elementType = 'constraint';
         if (!empty($tableData[$elementType])) {
             foreach ($tableData[$elementType] as $tableElementData) {
                 if ($tableElementData['type'] === 'foreign' && isset($tableElementData['referenceTable'])) {
-                    $referenceTable = $schema->getTableByName($tableElementData['referenceTable']);
-                    $column = $table->getColumnByName($tableElementData['column']);
-                    $referenceColumn = $referenceTable->getColumnByName($tableElementData['referenceColumn']);
-                    $constraintName = ($column !== false && $referenceColumn !== false) ?
-                        $this->elementNameResolver->getFullFKName(
-                            $table,
-                            $column,
-                            $referenceTable,
-                            $referenceColumn
-                        ) : null;
+                    $constraintName = $this->getConstraintName($schema, $tableName, $tableElementData);
                 } else {
                     $constraintName = $this->elementNameResolver->getFullIndexName(
                         $table,
                         $tableElementData['column'] ?? [],
-                        $tableElementData['type']
+                        $tableElementData['type'] ?? null
                     );
                 }
                 if ($constraintName) {
@@ -254,6 +223,34 @@ private function getConstraintName(Schema $schema, string $tableName, array $tab
         return $declaredStructure;
     }
 
+    /**
+     * Provide autogenerated names of the table constraint.
+     *
+     * @param Schema $schema
+     * @param string $tableName
+     * @param array $tableElementData
+     * @return string|null
+     */
+    private function getConstraintName(Schema $schema, string $tableName, array $tableElementData): ?string
+    {
+        $table = $schema->getTableByName($tableName);
+
+        $referenceTable = isset($tableElementData['referenceTable'])
+            ? $schema->getTableByName($tableElementData['referenceTable']) : false;
+        $column = isset($tableElementData['column'])
+            ? $table->getColumnByName($tableElementData['column']) : false;
+        $referenceColumn = isset($tableElementData['referenceColumn'])
+            ? $referenceTable->getColumnByName($tableElementData['referenceColumn']) : false;
+
+        return ($column !== false && $referenceColumn !== false && $referenceTable !== false) ?
+            $this->elementNameResolver->getFullFKName(
+                $table,
+                $column,
+                $referenceTable,
+                $referenceColumn
+            ) : null;
+    }
+
     /**
      * Load db_schema content from the primary scope app/etc/db_schema.xml.
      *