Added check for case sensitive duplicated file names

includes/Checker/Checks/Plugin_Repo/File_Type_Check.php

@@ -302,6 +302,49 @@ function ( $file ) use ( $plugin_path ) {
 				);
 			}
 		}
+
+		// Duplicated names in different folders.
+		$folders = array();
+		foreach ( $files as $file ) {
+			$folder = str_replace( basename( $file ), '', $file );
+			if ( empty( $folder ) ) {
+				continue;
+			}
+			$folders[] = $folder;
+		}
+		$folders                = array_unique( $folders );
+		$folders_lowercase      = array_map( 'strtolower', $folders );
+		$case_sensitive_folders = array_unique( array_diff_assoc( $folders_lowercase, array_unique( $folders_lowercase ) ) );
+
+		if ( ! empty( $case_sensitive_folders ) ) {
+			$this->add_result_error_for_file(
+				$result,
+				__( 'Case-Sensitive duplicated folders were found. They\'ll be problematic in different systems.', 'plugin-check' ),
+				'case_sensitive_folders',
+				implode( ', ', $case_sensitive_folders ),
+				0,
+				0,
+				'',
+				8
+			);
+		}
+
+		// Duplicated names in same folder.
+		$files_lowercase      = array_map( 'strtolower', $files );
+		$case_sensitive_files = array_unique( array_diff_assoc( $files_lowercase, array_unique( $files_lowercase ) ) );
+
+		if ( ! empty( $case_sensitive_files ) ) {
+			$this->add_result_error_for_file(
+				$result,
+				__( 'Case-Sensitive duplicated files were found. They\'ll be problematic in different systems.', 'plugin-check' ),
+				'case_sensitive_files',
+				implode( ', ', $case_sensitive_files ),
+				0,
+				0,
+				'',
+				8
+			);
+		}
 	}
 
 	/**

tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php

@@ -128,6 +128,48 @@ public function test_run_with_badly_named_errors() {
 		$this->assertCount( 1, wp_list_filter( $errors['badly|file%name!@#$%^&*()+=[]{};:"\'<>,?|`~.php'][0][0], array( 'code' => 'badly_named_files' ) ) );
 	}
 
+	public function test_run_with_case_sensitive_named_errors() {
+		// Initialize the Check_Context with a plugin path that mimics the directory structure.
+		$check_context = new Check_Context( UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/load.php' );
+
+		// Create an empty Check_Result instance for this context.
+		$check_result = new Check_Result( $check_context );
+
+		// Initialize the File_Type_Check instance.
+		$check = new File_Type_Check();
+
+		// Use reflection to make protected method accessible.
+		$reflection         = new ReflectionClass( $check );
+		$check_files_method = $reflection->getMethod( 'look_for_badly_named_files' );
+		$check_files_method->setAccessible( true );
+
+		// Define the custom file list with duplicate names as they would appear in a plugin directory.
+		$custom_files = array(
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/custom-file.php',
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/Custom-File.php',
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/custom-FILE.php',
+		);
+
+		// Invoke method with the Check_Result instance and custom file list.
+		$result = $check_files_method->invoke( $check, $check_result, $custom_files );
+
+		$errors = $check_result->get_errors();
+
+		$this->assertCount( 1, wp_list_filter( $errors['custom-file.php'][0][0], array( 'code' => 'case_sensitive_files' ) ) );
+
+		// Define the custom file list with duplicate folder names as they would appear in a plugin directory.
+		$custom_files = array(
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/sub directory/file-1.php',
+			UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/Sub Directory/file-2.php',
+		);
+
+		// Invoke method with the Check_Result instance and custom file list.
+		$result = $check_files_method->invoke( $check, $check_result, $custom_files );
+		$errors = $check_result->get_errors();
+
+		$this->assertCount( 1, wp_list_filter( $errors['sub directory/'][0][0], array( 'code' => 'case_sensitive_folders' ) ) );
+	}
+
 	public function test_run_with_library_core_errors() {
 		$check_context = new Check_Context( UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-library-core-errors/load.php' );
 		$check_result  = new Check_Result( $check_context );