Downgrade missing required CSV column from error to warning

When importing a CSV that doesn't contain all required columns defined
in the database schema, the validation was throwing an exception that
halted the entire import. This changes the behavior to emit a warning
instead, allowing the import to proceed with null values for missing
columns. The database layer will handle any actual constraint violations
on a per-row basis.

Fixes: CLOUD-3K9V

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: claudear

src/Migration/Sources/CSV.php

@@ -469,36 +469,33 @@ private function validateCSVHeaders(array $headers, array $columnTypes, array $r
         $internals = ['$id', '$permissions', '$createdAt', '$updatedAt'];
         $allKnown = \array_keys($columnTypes);
 
-        // Only validate that required columns are present
+        $messages = [];
+
+        // Check for missing required columns — warn but don't fail
         $missingRequired = [];
         foreach (\array_keys($requiredColumns) as $requiredColumn) {
             if (!\in_array($requiredColumn, $headers)) {
                 $missingRequired[] = $requiredColumn;
             }
         }
 
-        $messages = [];
-
-        // If there are missing required columns, throw an exception
         if (!empty($missingRequired)) {
             $label = \count($missingRequired) === 1 ? 'Missing required column' : 'Missing required columns';
-            $messages[] = "$label: '" . \implode("', '", $missingRequired) . "'";
-        }
-        if (!empty($missingRequired)) {
-            throw new \Exception('CSV header validation failed: ' . \implode('. ', $messages), Exception::CODE_VALIDATION);
+            $messages[] = "$label: '" . \implode("', '", $missingRequired) . "' (rows will have null values)";
         }
 
-        // If there are unknown columns but no missing required columns, just log a warning
+        // Check for unknown columns
         $unknown = \array_diff($headers, $allKnown, $internals);
         if (!empty($unknown)) {
             $label = \count($unknown) === 1 ? 'Unknown column' : 'Unknown columns';
             $messages[] = "$label: '" . \implode("', '", $unknown) . "' (will be ignored)";
         }
-        if (!empty($unknown)) {
+
+        if (!empty($messages)) {
             $this->addWarning(new Warning(
                 UtopiaResource::TYPE_ROW,
                 Transfer::GROUP_DATABASES,
-                \implode(', ', $messages),
+                \implode('. ', $messages),
                 $this->resourceId
             ));
         }

tests/Migration/Unit/General/CSVTest.php

@@ -416,6 +416,49 @@ public function testCSVExportImportCompatibility()
         }
     }
 
+    /**
+     * @throws \ReflectionException
+     */
+    private function callValidateCSVHeaders(array $headers, array $columnTypes, array $requiredColumns): void
+    {
+        $reflection = new \ReflectionClass(CSV::class);
+        $instance = $reflection->newInstanceWithoutConstructor();
+
+        $refProp = $reflection->getProperty('resourceId');
+        $refProp->setAccessible(true);
+        $refProp->setValue($instance, 'test_db:test_table');
+
+        $refMethod = $reflection->getMethod('validateCSVHeaders');
+        $refMethod->setAccessible(true);
+
+        $refMethod->invoke($instance, $headers, $columnTypes, $requiredColumns);
+    }
+
+    public function testValidateCSVHeadersMissingRequiredColumnDoesNotThrow(): void
+    {
+        // A CSV with only 'name' column, but 'texte' is required in the schema
+        $headers = ['name'];
+        $columnTypes = ['name' => 'string', 'texte' => 'string'];
+        $requiredColumns = ['texte' => true];
+
+        // This should NOT throw — missing required columns should be a warning, not an error
+        $this->callValidateCSVHeaders($headers, $columnTypes, $requiredColumns);
+
+        // If we reach here, the test passes (no exception thrown)
+        $this->assertTrue(true);
+    }
+
+    public function testValidateCSVHeadersAllRequiredPresent(): void
+    {
+        $headers = ['name', 'texte'];
+        $columnTypes = ['name' => 'string', 'texte' => 'string'];
+        $requiredColumns = ['texte' => true];
+
+        // Should not throw when all required columns are present
+        $this->callValidateCSVHeaders($headers, $columnTypes, $requiredColumns);
+        $this->assertTrue(true);
+    }
+
     private function recursiveDelete(string $dir): void
     {
         if (is_dir($dir)) {