From b1c0c2d8a1a482491b6219cb6fd77b1e1de4c8d4 Mon Sep 17 00:00:00 2001
From: kkmuffme <11071985+kkmuffme@users.noreply.github.com>
Date: Thu, 22 Sep 2022 00:10:27 +0200
Subject: [PATCH 1/2] add hideAllErrorsExceptPassedFiles config option

for files only (not directories, since that wouldn't make practical sense)
---
 src/Psalm/Config.php                            | 13 +++++++++++++
 src/Psalm/Internal/Analyzer/ProjectAnalyzer.php |  6 ++++++
 2 files changed, 19 insertions(+)

diff --git a/src/Psalm/Config.php b/src/Psalm/Config.php
index c97021c5ed3..72d7ae02b4c 100644
--- a/src/Psalm/Config.php
+++ b/src/Psalm/Config.php
@@ -295,6 +295,11 @@ class Config
      */
     public $hide_external_errors = false;
 
+    /**
+     * @var bool
+     */
+    public $hide_all_errors_except_passed_files = false;
+
     /** @var bool */
     public $allow_includes = true;
 
@@ -926,6 +931,7 @@ private static function fromXmlAndPaths(
             'useDocblockPropertyTypes' => 'use_docblock_property_types',
             'throwExceptionOnError' => 'throw_exception',
             'hideExternalErrors' => 'hide_external_errors',
+            'hideAllErrorsExceptPassedFiles' => 'hide_all_errors_except_passed_files',
             'resolveFromConfigFile' => 'resolve_from_config_file',
             'allowFileIncludes' => 'allow_includes',
             'strictBinaryOperands' => 'strict_binary_operands',
@@ -1567,6 +1573,13 @@ public function reportIssueInFile(string $issue_type, string $file_path): bool
 
         $project_analyzer = ProjectAnalyzer::getInstance();
 
+        // if the option is set and at least one file is passed via CLI
+        if ($this->hide_all_errors_except_passed_files
+            && $project_analyzer->check_paths_files
+            && !in_array($file_path, $project_analyzer->check_paths_files, true)) {
+            return false;
+        }
+
         $codebase = $project_analyzer->getCodebase();
 
         if (!$this->hide_external_errors) {
diff --git a/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php b/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php
index 40b3316df2a..21cc4ca0893 100644
--- a/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php
@@ -204,6 +204,11 @@ class ProjectAnalyzer
      */
     public $provide_completion = false;
 
+    /**
+     * @var list<string>
+     */
+    public $check_paths_files = [];
+
     /**
      * @var array<string,string>
      */
@@ -1178,6 +1183,7 @@ public function checkPaths(array $paths_to_check): void
             if (is_dir($path)) {
                 $this->checkDirWithConfig($path, $this->config, true);
             } elseif (is_file($path)) {
+                $this->check_paths_files[] = $path;
                 $this->codebase->addFilesToAnalyze([$path => $path]);
                 $this->config->hide_external_errors = $this->config->isInProjectDirs($path);
             }

From b68ac865e1ab2ed97d9e83471c3795b93b7d3c7f Mon Sep 17 00:00:00 2001
From: kkmuffme <11071985+kkmuffme@users.noreply.github.com>
Date: Sat, 24 Sep 2022 10:44:12 +0200
Subject: [PATCH 2/2] add docs

---
 docs/running_psalm/configuration.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/docs/running_psalm/configuration.md b/docs/running_psalm/configuration.md
index f24d4542cc8..6a7f4856bc2 100644
--- a/docs/running_psalm/configuration.md
+++ b/docs/running_psalm/configuration.md
@@ -400,6 +400,14 @@ Useful in testing, this makes Psalm throw a regular-old exception when it encoun
 ```
 Whether or not to show issues in files that are used by your project files, but which are not included in `<projectFiles>`. Defaults to `false`.
 
+#### hideAllErrorsExceptPassedFiles
+```xml
+<psalm
+  hideAllErrorsExceptPassedFiles="[bool]"
+>
+```
+Whether or not to report issues only for files that were passed explicitly as arguments in CLI. This means any files that are loaded with require/include will not report either, if not set in CLI. Useful if you want to only check errors in a single or selected files. Defaults to `false`.
+
 #### cacheDirectory
 ```xml
 <psalm