Check runtime requirements

src/Psalm/Internal/Cli/LanguageServer.php

@@ -61,6 +61,7 @@ final class LanguageServer
     /** @param array<int,string> $argv */
     public static function run(array $argv): void
     {
+        CliUtils::checkRuntimeRequirements();
         gc_disable();
         ErrorHandler::install($argv);
         $valid_short_options = [

src/Psalm/Internal/Cli/Plugin.php

@@ -26,6 +26,7 @@ final class Plugin
 {
     public static function run(): void
     {
+        CliUtils::checkRuntimeRequirements();
         $current_dir = (string)getcwd() . DIRECTORY_SEPARATOR;
         $vendor_dir = CliUtils::getVendorDir($current_dir);
         CliUtils::requireAutoloaders($current_dir, false, $vendor_dir);

src/Psalm/Internal/Cli/Psalm.php

@@ -165,6 +165,7 @@ final class Psalm
      */
     public static function run(array $argv): void
     {
+        CliUtils::checkRuntimeRequirements();
         gc_collect_cycles();
         gc_disable();
 

src/Psalm/Internal/Cli/Psalter.php

@@ -94,6 +94,7 @@ final class Psalter
     /** @param array<int,string> $argv */
     public static function run(array $argv): void
     {
+        CliUtils::checkRuntimeRequirements();
         gc_collect_cycles();
         gc_disable();
 

src/Psalm/Internal/Cli/Refactor.php

@@ -67,6 +67,7 @@ final class Refactor
     /** @param array<int,string> $argv */
     public static function run(array $argv): void
     {
+        CliUtils::checkRuntimeRequirements();
         ini_set('memory_limit', '8192M');
 
         gc_collect_cycles();

src/Psalm/Internal/CliUtils.php

@@ -13,11 +13,13 @@
 use Psalm\Report;
 use RuntimeException;
 
+use function array_filter;
 use function array_slice;
 use function assert;
 use function count;
 use function define;
 use function dirname;
+use function extension_loaded;
 use function fgets;
 use function file_exists;
 use function file_get_contents;
@@ -47,6 +49,8 @@
 use const DIRECTORY_SEPARATOR;
 use const JSON_THROW_ON_ERROR;
 use const PHP_EOL;
+use const PHP_VERSION;
+use const PHP_VERSION_ID;
 use const STDERR;
 use const STDIN;
 
@@ -88,7 +92,7 @@ public static function requireAutoloaders(
         foreach ($autoload_roots as $autoload_root) {
             $has_autoloader = false;
 
-            $nested_autoload_file = dirname($autoload_root, 2). DIRECTORY_SEPARATOR . 'autoload.php';
+            $nested_autoload_file = dirname($autoload_root, 2) . DIRECTORY_SEPARATOR . 'autoload.php';
 
             // note: don't realpath $nested_autoload_file, or phar version will fail
             if (file_exists($nested_autoload_file)) {
@@ -300,7 +304,7 @@ public static function getPathsToCheck($f_paths): ?array
             if ($stdin = fgets(STDIN)) {
                 $filtered_input_paths = preg_split('/\s+/', trim($stdin));
                 if ($filtered_input_paths === false) {
-                    throw new RuntimeException('Invalid paths: '.preg_last_error_msg());
+                    throw new RuntimeException('Invalid paths: ' . preg_last_error_msg());
                 }
             }
             $blocked = $meta['blocked'];
@@ -515,4 +519,54 @@ public static function runningInCI(): bool
             || isset($_SERVER['GITHUB_WORKFLOW'])
             || isset($_SERVER['DRONE']);
     }
+
+    public static function checkRuntimeRequirements(): void
+    {
+        $required_php_version = 7_04_00;
+        $required_php_version_text = '7.4.0';
+
+        // the following list was taken from vendor/composer/platform_check.php
+        // It includes both Psalm's requirements (from composer.json) and the
+        // requirements of our dependencies `netresearch/jsonmapper` and
+        // `phpdocumentor/reflection-docblock`. The latter is transitive
+        // dependency of `felixfbecker/advanced-json-rpc`
+        $required_extensions = [
+            'dom',
+            'filter',
+            'json',
+            'libxml',
+            'pcre',
+            'reflection',
+            'simplexml',
+            'spl',
+            'tokenizer',
+        ];
+        $issues = [];
+
+        if (PHP_VERSION_ID < $required_php_version) {
+            $issues[] = 'Psalm requires a PHP version ">= ' . $required_php_version_text . '".'
+                        . ' You are running ' . PHP_VERSION . '.';
+        }
+
+        $missing_extensions = array_filter(
+            $required_extensions,
+            static fn(string $ext) => !extension_loaded($ext)
+        );
+
+        if ($missing_extensions) {
+            $issues[] = 'Psalm requires the following PHP extensions to be installed: '
+                        . implode(', ', $missing_extensions)
+                        . '.';
+        }
+
+        if ($issues) {
+            fwrite(
+                STDERR,
+                'Psalm has detected issues in your platform:' . PHP_EOL . PHP_EOL
+                . implode(PHP_EOL, $issues)
+                . PHP_EOL . PHP_EOL
+            );
+            exit(1);
+        }
+    }
 }