Subject: [PATCH v2 1/3] store: Tolerate non-existent GC root directories.

From: Ludovic Courtès <[email-masked]>
Date: Thu, 8 Jun 2023 00:09:52 +0200

* guix/store/roots.scm (gc-roots): Wrap 'scandir*' call in 'catch'.
* tests/store-roots.scm ("gc-roots, initial"): New test.  Move
'open-connection' call below.
---
 guix/store/roots.scm  | 12 ++++++++++--
 tests/store-roots.scm | 18 +++++++++++++++---
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/guix/store/roots.scm b/guix/store/roots.scm
index 222f69c5c0..6b949b5a86 100644
--- a/guix/store/roots.scm
+++ b/guix/store/roots.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2014, 2017, 2019 Ludovic Courtès <[email-masked]>
+;;; Copyright © 2012-2014, 2017, 2019, 2023 Ludovic Courtès <[email-masked]>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -105,7 +105,15 @@ (define (gc-roots)
                                      (map (match-lambda
                                             ((file . properties)
                                              (cons (scope file) properties)))
-                                          (scandir* directory regular?)))))
+                                          (catch 'system-error
+                                            (lambda ()
+                                              (scandir* directory regular?))
+                                            (lambda args
+                                              (if (= ENOENT
+                                                     (system-error-errno
+                                                      args))
+                                                  '()
+                                                  (apply throw args))))))))
              (loop (append rest (map first sub-directories))
                    (append (map canonical-root (filter symlink? files))
                            roots)
diff --git a/tests/store-roots.scm b/tests/store-roots.scm
index 5bcf1bc87e..9877987a65 100644
--- a/tests/store-roots.scm
+++ b/tests/store-roots.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2019 Ludovic Courtès <[email-masked]>
+;;; Copyright © 2019, 2023 Ludovic Courtès <[email-masked]>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -21,14 +21,26 @@ (define-module (test-store-deduplication)
   #:use-module (guix store)
   #:use-module (guix store roots)
   #:use-module ((guix utils) #:select (call-with-temporary-directory))
+  #:use-module ((guix build utils) #:select (delete-file-recursively))
+  #:use-module ((guix config) #:select (%state-directory))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-64))
 
-(define %store
-  (open-connection))
+(define %store #f)
 
 (test-begin "store-roots")
 
+(test-equal "gc-roots, initial"
+  (list (string-append %state-directory "/profiles"))
+  (begin
+    ;; 'gc-roots' should gracefully handle lack of that directory.
+    (delete-file-recursively (string-append %state-directory "/profiles"))
+    (gc-roots)))
+
+;; The 'open-connection' call below gets guix-daemon to create
+;; %STATE-DIRECTORY/profiles.
+(set! %store (open-connection))
+
 (test-assert "gc-roots, regular root"
   (let* ((item (add-text-to-store %store "something"
                                   (random-text)))
-- 
2.40.1