Add BeforeAnalyzeFileInterface (#2034)

This is a prerequisite of the plugin I mentioned in #378

This may be useful for other types of plugins
(e.g. checking raw file contents or file names)

src/Psalm/Config.php

@@ -422,6 +422,12 @@ class Config
      */
     public $after_analysis = [];
 
+    /**
+     * Static methods to be called after codebase has been populated
+     * @var class-string<Hook\BeforeAnalyzeFileInterface>[]
+     */
+    public $before_analyze_file = [];
+
     /** @var array<string, mixed> */
     private $predefined_constants;
 

src/Psalm/Internal/Analyzer/FileAnalyzer.php

@@ -163,6 +163,9 @@ class FileAnalyzer extends SourceAnalyzer implements StatementsSource
         } catch (PhpParser\Error $e) {
             return;
         }
+        foreach ($codebase->config->before_analyze_file as $plugin_class) {
+            $plugin_class::beforeAnalyzeFile($this);
+        }
 
         if ($codebase->alter_code) {
             foreach ($stmts as $stmt) {

src/Psalm/Plugin/Hook/BeforeAnalyzeFileInterface.php

@@ -0,0 +1,14 @@
+<?php
+namespace Psalm\Plugin\Hook;
+
+use Psalm\Internal\Analyzer\FileAnalyzer;
+
+interface BeforeAnalyzeFileInterface
+{
+    /**
+     * @return void
+     */
+    public static function beforeAnalyzeFile(
+        FileAnalyzer $file_analyzer
+    );
+}