diff --git a/core/modules/file/src/Plugin/Validation/Constraint/FileEncodingConstraint.php b/core/modules/file/src/Plugin/Validation/Constraint/FileEncodingConstraint.php
new file mode 100644
index 0000000000000000000000000000000000000000..5416fd760423c37abb1a699d3fb242be3e4fdad8
--- /dev/null
+++ b/core/modules/file/src/Plugin/Validation/Constraint/FileEncodingConstraint.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\file\Plugin\Validation\Constraint;
+
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\Core\Validation\Attribute\Constraint;
+use Symfony\Component\Validator\Constraint as SymfonyConstraint;
+
+/**
+ * Defines an encoding constraint for files.
+ */
+#[Constraint(
+ id: 'FileEncoding',
+ label: new TranslatableMarkup('File encoding', [], ['context' => 'Validation'])
+)]
+class FileEncodingConstraint extends SymfonyConstraint {
+
+ /**
+ * The error message.
+ *
+ * @var string
+ */
+ public string $message = "The file is encoded with %detected. It must be encoded with %encoding";
+
+ /**
+ * The allowed file encodings.
+ *
+ * @var array
+ */
+ public array $encodings;
+
+}
diff --git a/core/modules/file/src/Plugin/Validation/Constraint/FileEncodingConstraintValidator.php b/core/modules/file/src/Plugin/Validation/Constraint/FileEncodingConstraintValidator.php
new file mode 100644
index 0000000000000000000000000000000000000000..e6b580c80d693420ffe06d1f70c6367f1f6a9a2b
--- /dev/null
+++ b/core/modules/file/src/Plugin/Validation/Constraint/FileEncodingConstraintValidator.php
@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\file\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+/**
+ * Validates the file encoding constraint.
+ */
+class FileEncodingConstraintValidator extends BaseFileConstraintValidator {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function validate(mixed $value, Constraint $constraint): void {
+
+ /** @var \Drupal\file\Entity\FileInterface $file */
+ $file = $this->assertValueIsFile($value);
+ if (!$constraint instanceof FileEncodingConstraint) {
+ throw new UnexpectedTypeException($constraint, FileEncodingConstraint::class);
+ }
+
+ $encodings = $constraint->encodings;
+ $data = file_get_contents($file->getFileUri());
+ foreach ($encodings as $encoding) {
+ $this->validateEncoding($data, $encoding, $constraint);
+ }
+ }
+
+ /**
+ * Validates the encoding of the file.
+ *
+ * @param string $data
+ * The file data.
+ * @param string $encoding
+ * The encoding to validate.
+ * @param \Drupal\file\Plugin\Validation\Constraint\FileEncodingConstraint $constraint
+ * The constraint.
+ */
+ protected function validateEncoding(string $data, string $encoding, FileEncodingConstraint $constraint): void {
+ if (mb_check_encoding($data, $encoding)) {
+ return;
+ }
+ $this->context->addViolation($constraint->message, [
+ '%encoding' => $encoding,
+ '%detected' => mb_detect_encoding($data),
+ ]);
+ }
+
+}
diff --git a/core/modules/file/tests/src/Kernel/Plugin/Validation/Constraint/FileEncodingConstraintValidatorTest.php b/core/modules/file/tests/src/Kernel/Plugin/Validation/Constraint/FileEncodingConstraintValidatorTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..1dd03fa84346eab666bcd969ffb5903daa2bf0b8
--- /dev/null
+++ b/core/modules/file/tests/src/Kernel/Plugin/Validation/Constraint/FileEncodingConstraintValidatorTest.php
@@ -0,0 +1,106 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\file\Kernel\Plugin\Validation\Constraint;
+
+use Drupal\file\Entity\File;
+use Drupal\Tests\file\Kernel\Validation\FileValidatorTestBase;
+
+// cspell:ignore räme
+
+/**
+ * Tests the FileEncodingConstraintValidator.
+ *
+ * @group file
+ * @coversDefaultClass \Drupal\file\Plugin\Validation\Constraint\FileEncodingConstraintValidator
+ */
+class FileEncodingConstraintValidatorTest extends FileValidatorTestBase {
+
+ /**
+ * Tests the FileEncodingConstraintValidator.
+ *
+ * @param array $file_properties
+ * The properties of the file being validated.
+ * @param string[] $encodings
+ * An array of the allowed file encodings.
+ * @param string[] $expected_errors
+ * The expected error messages as string.
+ *
+ * @dataProvider providerTestFileValidateEncodings
+ * @covers ::validate
+ */
+ public function testFileEncodings(array $file_properties, array $encodings, array $expected_errors): void {
+ $data = 'Räme';
+ $data = mb_convert_encoding($data, $file_properties['encoding']);
+ file_put_contents($file_properties['uri'], $data);
+ $file = File::create($file_properties);
+ // Test for failure.
+ $validators = [
+ 'FileEncoding' => [
+ 'encodings' => $encodings,
+ ],
+ ];
+
+ $violations = $this->validator->validate($file, $validators);
+ $actual_errors = [];
+ foreach ($violations as $violation) {
+ $actual_errors[] = $violation->getMessage();
+ }
+ $this->assertEquals($expected_errors, $actual_errors);
+ }
+
+ /**
+ * Data provider for ::testFileEncoding.
+ *
+ * @return array[][]
+ * The test cases.
+ */
+ public static function providerTestFileValidateEncodings(): array {
+ $utf8_encoded_txt_file_properties = [
+ 'filename' => 'druplicon.txt',
+ 'uri' => 'public://druplicon.txt',
+ 'status' => 0,
+ 'encoding' => 'UTF-8',
+ ];
+ $windows1252_encoded_txt_file = [
+ 'filename' => 'druplicon-win.txt',
+ 'uri' => 'public://druplicon-win.txt',
+ 'status' => 1,
+ 'encoding' => 'windows-1252',
+ ];
+ return [
+ 'UTF-8 encoded file validated with "UTF-8" encoding' => [
+ 'file_properties' => $utf8_encoded_txt_file_properties,
+ 'encodings' => ['UTF-8'],
+ 'expected_errors' => [],
+ ],
+ 'Windows-1252 encoded file validated with "UTF-8" encoding' => [
+ 'file_properties' => $windows1252_encoded_txt_file,
+ 'encodings' => ['UTF-8'],
+ 'expected_errors' => [
+ 'The file is encoded with ASCII. It must be encoded with UTF-8',
+ ],
+ ],
+ ];
+ }
+
+ /**
+ * Helper function that returns a .po file with invalid encoding.
+ */
+ public function getInvalidEncodedPoFile() {
+ return <<< EOF
+msgid ""
+msgstr ""
+"Project-Id-Version: Drupal 8\\n"
+"MIME-Version: 1.0\\n"
+"Content-Type: text/plain; charset=Windows-1252\\n"
+"Content-Transfer-Encoding: 8bit\\n"
+"Plural-Forms: nplurals=2; plural=(n > 1);\\n"
+
+msgid "Swamp"
+msgstr "Räme"
+EOF;
+ }
+
+}
diff --git a/core/modules/locale/src/Form/ImportForm.php b/core/modules/locale/src/Form/ImportForm.php
index 132adb194ed760d7fe7f4119c9299f6d94362adf..544332fde100a9b545dbceb55647fbafd7e3b14e 100644
--- a/core/modules/locale/src/Form/ImportForm.php
+++ b/core/modules/locale/src/Form/ImportForm.php
@@ -101,6 +101,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
$validators = [
'FileExtension' => ['extensions' => 'po'],
'FileSizeLimit' => ['fileLimit' => Environment::getUploadMaxSize()],
+ 'FileEncoding' => ['encodings' => ['UTF-8']],
];
$form['file'] = [
'#type' => 'file',
diff --git a/core/modules/locale/tests/src/Functional/LocaleImportFunctionalTest.php b/core/modules/locale/tests/src/Functional/LocaleImportFunctionalTest.php
index af93c0e99c251b9ffe254aa638949af3af4b4269..db50cef067194814c47ca9f4d740441a6594df54 100644
--- a/core/modules/locale/tests/src/Functional/LocaleImportFunctionalTest.php
+++ b/core/modules/locale/tests/src/Functional/LocaleImportFunctionalTest.php
@@ -11,7 +11,7 @@
use Drupal\Tests\BrowserTestBase;
// cspell:ignore chien chiens deutsch januari lundi montag moutons műveletek
-// cspell:ignore svibanj
+// cspell:ignore svibanj räme
/**
* Tests the import of locale files.
@@ -250,6 +250,9 @@ public function testStandalonePoFile(): void {
$this->submitForm($search, 'Filter');
$this->assertSession()->pageTextNotContains('No strings available.');
+ // Try importing a .po file with invalid encoding.
+ $this->importPoFile($this->getInvalidEncodedPoFile(), [], ['Windows-1252']);
+ $this->assertSession()->pageTextContains('The file is encoded with ASCII. It must be encoded with UTF-8');
}
/**
@@ -402,10 +405,15 @@ public function testCreatedLanguageTranslation(): void {
* Contents of the .po file to import.
* @param array $options
* (optional) Additional options to pass to the translation import form.
+ * @param array $encodings
+ * (optional) The encoding of the file.
*/
- public function importPoFile($contents, array $options = []) {
+ public function importPoFile($contents, array $options = [], array $encodings = []) {
$file_system = \Drupal::service('file_system');
$name = $file_system->tempnam('temporary://', "po_") . '.po';
+ foreach ($encodings as $encoding) {
+ $contents = mb_convert_encoding($contents, $encoding);
+ }
file_put_contents($name, $contents);
$options['files[file]'] = $name;
$this->drupalGet('admin/config/regional/translate/import');
@@ -672,6 +680,24 @@ public function getPoFileWithConfigDe() {
msgid "German"
msgstr "Deutsch"
+EOF;
+ }
+
+ /**
+ * Helper function that returns a .po file with invalid encoding.
+ */
+ public function getInvalidEncodedPoFile() {
+ return <<< EOF
+msgid ""
+msgstr ""
+"Project-Id-Version: Drupal 8\\n"
+"MIME-Version: 1.0\\n"
+"Content-Type: text/plain; charset=Windows-1252\\n"
+"Content-Transfer-Encoding: 8bit\\n"
+"Plural-Forms: nplurals=2; plural=(n > 1);\\n"
+
+msgid "Swamp"
+msgstr "Räme"
EOF;
}