From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: 58812@debbugs.gnu.org
Subject: [bug#58812] [PATCH 0/5] Add --symlink option to 'guix shell'.
Date: Wed, 09 Nov 2022 22:37:46 -0500 [thread overview]
Message-ID: <877d03xywl.fsf@gmail.com> (raw)
In-Reply-To: <87leojon1z.fsf_-_@gnu.org> ("Ludovic Courtès"'s message of "Wed, 09 Nov 2022 22:06:16 +0100")
Hi again,
Ludovic Courtès <ludo@gnu.org> writes:
> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>
>> * gnu/build/install.scm (evaluate-populate-directive): By default, error when
>> the target of a symlink doesn't exist. Always ensure TARGET ends with "/".
>> (populate-root-file-system): Call evaluate-populate-directive with
>> #:error-on-dangling-symlink #t and add comment.
>
> [...]
>
>> + (define target* (if (string-suffix? "/" target)
>> + target
>> + (string-append target "/")))
>
> Maybe make it:
>
> (let ((target (if …)))
> …)
>
> so there’s only one ‘target’ in scope (and no ‘target*’); otherwise it’s
> easy to forget the ‘*’ and refer to wrong one.
It's a pattern I've used at other places; I find it more hygienic to not
shadow existing variables; it signal to the reader "be careful, this is
not the same as the argument-bound one, though they are closely
related".
>> + (when error-on-dangling-symlink?
>> + ;; When the symbolic link points to a relative path,
>> + ;; checking if its target exists must be done relative to
>> + ;; the link location.
>> + (with-directory-excursion (if (string-prefix? "/" old)
>> + (getcwd)
>> + (dirname new*)) ;relative
>> + (unless (file-exists? old)
>> + (error (format #f "symlink `~a' points to nonexistent \
>> +file `~a'" new* old)))))
>> + (symlink old new*))
>
> I would avoid the directory excursion when unnecessary:
>
> (unless (if (string-prefix? "/" old)
> (file-exists? old)
> (with-directory-excursion (dirname new)
> (file-exists? old)))
> …)
Done:
--8<---------------cut here---------------start------------->8---
modified gnu/build/install.scm
@@ -99,14 +99,14 @@ (define target* (if (string-suffix? "/" target)
(lambda ()
(when error-on-dangling-symlink?
;; When the symbolic link points to a relative path,
- ;; checking if its target exists must be done relative to
- ;; the link location.
- (with-directory-excursion (if (string-prefix? "/" old)
- (getcwd)
- (dirname new*)) ;relative
- (unless (file-exists? old)
- (error (format #f "symlink `~a' points to nonexistent \
-file `~a'" new* old)))))
+ ;; checking if its target exists must be done relatively
+ ;; to the link location.
+ (unless (if (string-prefix? "/" old)
+ (file-exists? old)
+ (with-directory-excursion (dirname new*)
+ (file-exists? old)))
+ (error (format #f "symlink `~a' points to nonexistent \
+file `~a'" new* old))))
(symlink old new*))
--8<---------------cut here---------------end--------------->8---
> (We could use ‘lstat’ instead of ‘file-exists?’ if we want to allow
> symlinks to dangling symlinks…)
It seems better to leave it as-is; the odd use case of symlinking to a
dangling symlink can be accomplished via "#:error-on-dangling-symlink
#f" :-).
--
Thanks,
Maxim
next prev parent reply other threads:[~2022-11-10 3:38 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-27 3:41 [bug#58812] [PATCH 0/5] Add --symlink option to 'guix shell' Maxim Cournoyer
2022-10-27 3:50 ` [bug#58812] [PATCH 1/5] Makefile.am: Sort EXTRA_DIST entries Maxim Cournoyer
2022-10-27 3:50 ` [bug#58812] [PATCH 2/5] tests: Add a tests/utils.sh support file Maxim Cournoyer
2022-11-09 21:07 ` [bug#58812] [PATCH 0/5] Add --symlink option to 'guix shell' Ludovic Courtès
2022-11-10 3:38 ` Maxim Cournoyer
2022-11-10 4:23 ` [bug#59164] [PATCH v2 1/4] Makefile.am: Sort EXTRA_DIST entries Maxim Cournoyer
2022-11-10 4:23 ` [bug#59161] [PATCH v2 2/4] install: Validate symlink target in evaluate-populate-directive Maxim Cournoyer
2022-11-10 4:23 ` [bug#59162] [PATCH v2 3/4] guix: shell: Add '--symlink' option Maxim Cournoyer
2022-11-10 4:23 ` [bug#59163] [PATCH v2 4/4] shell: Detect --symlink spec problems early Maxim Cournoyer
2022-10-27 3:50 ` [bug#58812] [PATCH 3/5] install: Validate symlink target in evaluate-populate-directive Maxim Cournoyer
2022-11-09 21:06 ` [bug#58812] [PATCH 0/5] Add --symlink option to 'guix shell' Ludovic Courtès
2022-11-10 3:37 ` Maxim Cournoyer [this message]
2022-11-17 17:37 ` [bug#59164] Coding style: similarly-named variables Ludovic Courtès
2022-11-17 18:44 ` [bug#58812] " zimoun
2022-11-18 17:02 ` Maxim Cournoyer
2022-11-21 15:02 ` zimoun
2022-11-21 15:52 ` [bug#59164] " zimoun
2022-11-21 20:55 ` Maxim Cournoyer
2022-11-22 14:35 ` [bug#59164] " zimoun
2022-11-26 14:47 ` Ludovic Courtès
2022-11-17 20:34 ` Maxim Cournoyer
2022-11-20 10:46 ` [bug#58812] " Ludovic Courtès
2022-10-27 3:50 ` [bug#58812] [PATCH 4/5] guix: shell: Add '--symlink' option Maxim Cournoyer
2022-11-09 20:58 ` [bug#58812] [PATCH 0/5] Add --symlink option to 'guix shell' Ludovic Courtès
2022-11-10 3:10 ` Maxim Cournoyer
2022-11-10 14:17 ` Ludovic Courtès
2022-11-10 14:49 ` Maxim Cournoyer
2022-11-10 15:16 ` Maxim Cournoyer
2022-11-14 9:18 ` Ludovic Courtès
2022-11-10 16:05 ` [bug#58812] [PATCH v3 1/4] Makefile.am: Sort EXTRA_DIST entries Maxim Cournoyer
2022-11-10 16:05 ` [bug#58812] [PATCH v3 2/4] install: Validate symlink target in evaluate-populate-directive Maxim Cournoyer
2022-11-10 16:05 ` [bug#58812] [PATCH v3 3/4] guix: shell: Add '--symlink' option Maxim Cournoyer
2022-11-10 16:05 ` [bug#58812] [PATCH v3 4/4] shell: Detect --symlink spec problems early Maxim Cournoyer
2022-11-16 19:03 ` [bug#58812] [PATCH 0/5] Add --symlink option to 'guix shell' zimoun
2022-11-16 19:34 ` Maxim Cournoyer
2022-10-27 3:51 ` [bug#58812] [PATCH 5/5] shell: Detect --symlink spec problems early Maxim Cournoyer
2022-11-15 21:24 ` bug#58812: [PATCH v3 1/4] " Maxim Cournoyer
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