Upgrade to PHP 8.1 (#6711)

* Upgrade to PHP 8.1
As discussed in https://github.com/FreshRSS/FreshRSS/discussions/5474

https://www.php.net/releases/8.0/en.php
https://www.php.net/releases/8.1/en.php

Upgrade to available native type declarations
https://php.net/language.types.declarations

Upgrade to https://phpunit.de/announcements/phpunit-10.html which requires PHP 8.1+ (good timing, as version 9 was not maintained anymore)

Upgrade `:oldest` Docker dev image to oldest Alpine version supporting PHP 8.1: Alpine 3.16, which includes PHP 8.1.22.

* Include 6736
https://github.com/FreshRSS/FreshRSS/pull/6736

4 files changed, 4 insertions, 8 deletions

diff --git a/cli/_cli.php b/cli/_cli.php
index 9d9d9c32d..9486405aa 100755
--- a/cli/_cli.php
+++ b/cli/_cli.php
@@ -20,8 +20,7 @@ Minz_Translate::init('en');
 
 FreshRSS_Context::$isCli = true;
 
-/** @return never */
-function fail(string $message, int $exitCode = 1) {
+function fail(string $message, int $exitCode = 1): never {
 	fwrite(STDERR, $message . "\n");
 	die($exitCode);
 }
@@ -51,8 +50,7 @@ function accessRights(): void {
 		"\t", 'sudo cli/access-permissions.sh', "\n";
 }
 
-/** @return never */
-function done(bool $ok = true) {
+function done(bool $ok = true): never {
 	if (!$ok) {
 		fwrite(STDERR, (empty($_SERVER['argv'][0]) ? 'Process' : basename($_SERVER['argv'][0])) . ' failed!' . "\n");
 	}
diff --git a/cli/check.translation.php b/cli/check.translation.php
index 0da415d85..b452054ed 100755
--- a/cli/check.translation.php
+++ b/cli/check.translation.php
@@ -102,9 +102,8 @@ function findUsedTranslations(): array {
 
 /**
  * Output help message.
- * @return never
  */
-function checkHelp() {
+function checkHelp(): never {
 	$file = str_replace(__DIR__ . '/', '', __FILE__);
 
 	echo <<<HELP
diff --git a/cli/i18n/I18nFile.php b/cli/i18n/I18nFile.php
index 8085164c5..5d310d6bf 100644
--- a/cli/i18n/I18nFile.php
+++ b/cli/i18n/I18nFile.php
@@ -82,7 +82,6 @@ class I18nFile {
 	 * Flatten an array of translation
 	 *
 	 * @param array<string,I18nValue|array<string,I18nValue>> $translation
-	 * @param string $prefix
 	 * @return array<string,I18nValue>
 	 */
 	private function flatten(array $translation, string $prefix = ''): array {
diff --git a/cli/i18n/I18nValue.php b/cli/i18n/I18nValue.php
index 03e7676ae..aa2a670e1 100644
--- a/cli/i18n/I18nValue.php
+++ b/cli/i18n/I18nValue.php
@@ -32,7 +32,7 @@ class I18nValue {
 		}
 	}
 
-	public function __clone() {
+	public function __clone(): void {
 		$this->markAsTodo();
 	}