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03/03: scripts: time-machine: Error when attempting to visit too old com
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From: |
guix-commits |
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Subject: |
03/03: scripts: time-machine: Error when attempting to visit too old commits. |
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Date: |
Wed, 16 Aug 2023 21:40:30 -0400 (EDT) |
apteryx pushed a commit to branch master
in repository guix.
commit 79ec651a286c71a3d4c72be33a1f80e76a560031
Author: Maxim Cournoyer <maxim.cournoyer@gmail.com>
AuthorDate: Wed Jul 19 11:31:50 2023 -0400
scripts: time-machine: Error when attempting to visit too old commits.
* doc/guix.texi (Invoking guix time-machine): Document limitation.
* guix/inferior.scm (cached-channel-instance): New VALIDATE-CHANNELS
argument. Use it to validate channels when there are no cache hit.
* guix/scripts/time-machine.scm
(%options): Tag the given reference with 'tag-or-commit instead of 'commit.
(%oldest-possible-commit): New variable.
(guix-time-machine) <validate-guix-channel>: New nested procedure. Pass it
to
the 'cached-channel-instance' call.
* tests/guix-time-machine.sh: New test.
* Makefile.am (SH_TESTS): Register it.
Suggested-by: Simon Tournier <zimon.toutoune@gmail.com>
Reviewed-by: Ludovic Courtès <ludo@gnu.org>
Reviewed-by: Simon Tournier <zimon.toutoune@gmail.com>
---
Makefile.am | 1 +
doc/guix.texi | 17 +++++++++++++
guix/inferior.scm | 57 ++++++++++++++++++++++++-------------------
guix/scripts/time-machine.scm | 38 ++++++++++++++++++++++++++---
tests/guix-time-machine.sh | 28 +++++++++++++++++++++
5 files changed, 113 insertions(+), 28 deletions(-)
diff --git a/Makefile.am b/Makefile.am
index 5ffcb6a12d..4228c07803 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -615,6 +615,7 @@ SH_TESTS = \
tests/guix-refresh.sh \
tests/guix-shell.sh \
tests/guix-shell-export-manifest.sh \
+ tests/guix-time-machine.sh \
tests/guix-graph.sh \
tests/guix-describe.sh \
tests/guix-repl.sh \
diff --git a/doc/guix.texi b/doc/guix.texi
index 633d62bd98..e09083c1f8 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -5070,6 +5070,23 @@ opens the door to security vulnerabilities.
@xref{Invoking guix pull,
@option{--allow-downgrades}}.
@end quotation
+Due to @command{guix time-machine} relying on the ``inferiors''
+mechanism (@pxref{Inferiors}), the oldest commit it can travel to is
+commit @samp{6298c3ff} (``v1.0.0''), dated May 1@sup{st}, 2019, which is
+the first release that included the inferiors mechanism. An error is
+returned when attempting to navigate to older commits.
+
+@quotation Note
+Although it should technically be possible to travel to such an old
+commit, the ease to do so will largely depend on the availability of
+binary substitutes. When traveling to a distant past, some packages may
+not easily build from source anymore. One such example are old versions
+of Python 2 which had time bombs in its test suite, in the form of
+expiring SSL certificates. This particular problem can be worked around
+by setting the hardware clock to a value in the past before attempting
+the build.
+@end quotation
+
The general syntax is:
@example
diff --git a/guix/inferior.scm b/guix/inferior.scm
index 5dfd30a6c8..fca6fb4b22 100644
--- a/guix/inferior.scm
+++ b/guix/inferior.scm
@@ -871,11 +871,15 @@ prefix, resolve it; and if 'commit' is unset, fetch
CHANNEL's branch tip."
#:key
(authenticate? #t)
(cache-directory (%inferior-cache-directory))
- (ttl (* 3600 24 30)))
+ (ttl (* 3600 24 30))
+ validate-channels)
"Return a directory containing a guix filetree defined by CHANNELS, a list
of channels.
-The directory is a subdirectory of CACHE-DIRECTORY, where entries can be
reclaimed after TTL seconds.
-This procedure opens a new connection to the build daemon. AUTHENTICATE?
-determines whether CHANNELS are authenticated."
+The directory is a subdirectory of CACHE-DIRECTORY, where entries can be
+reclaimed after TTL seconds. This procedure opens a new connection to the
+build daemon. AUTHENTICATE? determines whether CHANNELS are authenticated.
+VALIDATE-CHANNELS, if specified, must be a one argument procedure accepting a
+list of channels that can be used to validate the channels; it should raise an
+exception in case of problems."
(define commits
;; Since computing the instances of CHANNELS is I/O-intensive, use a
;; cheaper way to get the commit list of CHANNELS. This limits overhead
@@ -923,27 +927,30 @@ determines whether CHANNELS are authenticated."
(if (file-exists? cached)
cached
- (run-with-store store
- (mlet* %store-monad ((instances
- -> (latest-channel-instances store channels
- #:authenticate?
- authenticate?))
- (profile
- (channel-instances->derivation instances)))
- (mbegin %store-monad
- ;; It's up to the caller to install a build handler to report
- ;; what's going to be built.
- (built-derivations (list profile))
-
- ;; Cache if and only if AUTHENTICATE? is true.
- (if authenticate?
- (mbegin %store-monad
- (symlink* (derivation->output-path profile) cached)
- (add-indirect-root* cached)
- (return cached))
- (mbegin %store-monad
- (add-temp-root* (derivation->output-path profile))
- (return (derivation->output-path profile)))))))))
+ (begin
+ (when (procedure? validate-channels)
+ (validate-channels channels))
+ (run-with-store store
+ (mlet* %store-monad ((instances
+ -> (latest-channel-instances store channels
+ #:authenticate?
+ authenticate?))
+ (profile
+ (channel-instances->derivation instances)))
+ (mbegin %store-monad
+ ;; It's up to the caller to install a build handler to report
+ ;; what's going to be built.
+ (built-derivations (list profile))
+
+ ;; Cache if and only if AUTHENTICATE? is true.
+ (if authenticate?
+ (mbegin %store-monad
+ (symlink* (derivation->output-path profile) cached)
+ (add-indirect-root* cached)
+ (return cached))
+ (mbegin %store-monad
+ (add-temp-root* (derivation->output-path profile))
+ (return (derivation->output-path profile))))))))))
(define* (inferior-for-channels channels
#:key
diff --git a/guix/scripts/time-machine.scm b/guix/scripts/time-machine.scm
index d7c71ef705..e4fe511382 100644
--- a/guix/scripts/time-machine.scm
+++ b/guix/scripts/time-machine.scm
@@ -2,6 +2,7 @@
;;; Copyright © 2019 Konrad Hinsen <konrad.hinsen@fastmail.net>
;;; Copyright © 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2021 Simon Tournier <zimon.toutoune@gmail.com>
+;;; Copyright © 2023 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -19,13 +20,15 @@
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix scripts time-machine)
+ #:use-module (guix channels)
+ #:use-module (guix diagnostics)
#:use-module (guix ui)
#:use-module (guix scripts)
#:use-module (guix inferior)
#:use-module (guix store)
#:use-module (guix status)
#:use-module ((guix git)
- #:select (with-git-error-handling))
+ #:select (update-cached-checkout with-git-error-handling))
#:use-module ((guix utils)
#:select (%current-system))
#:use-module ((guix scripts pull)
@@ -38,9 +41,17 @@
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-26)
+ #:use-module (srfi srfi-34)
#:use-module (srfi srfi-37)
+ #:use-module (srfi srfi-71)
#:export (guix-time-machine))
+;;; The required inferiors mechanism relied on by 'guix time-machine' was
+;;; firmed up in v1.0.0; it is the oldest, safest commit that can be travelled
+;;; to.
+(define %oldest-possible-commit
+ "6298c3ffd9654d3231a6f25390b056483e8f407c") ;v1.0.0
+
;;;
;;; Command-line options.
@@ -81,7 +92,7 @@ Execute COMMAND ARGS... in an older version of Guix.\n"))
(alist-delete 'repository-url result))))
(option '("commit") #t #f
(lambda (opt name arg result)
- (alist-cons 'ref `(commit . ,arg) result)))
+ (alist-cons 'ref `(tag-or-commit . ,arg) result)))
(option '("branch") #t #f
(lambda (opt name arg result)
(alist-cons 'ref `(branch . ,arg) result)))
@@ -140,8 +151,27 @@ Execute COMMAND ARGS... in an older version of Guix.\n"))
(let* ((opts (parse-args args))
(channels (channel-list opts))
(command-line (assoc-ref opts 'exec))
+ (ref (assoc-ref opts 'ref))
(substitutes? (assoc-ref opts 'substitutes?))
(authenticate? (assoc-ref opts 'authenticate-channels?)))
+
+ (define (validate-guix-channel channels)
+ "Finds the Guix channel among CHANNELS, and validates that REF as
+captured from the closure, a git reference specification such as a commit hash
+or tag associated to CHANNEL, is valid and new enough to satisfy the 'guix
+time-machine' requirements. A `formatted-message' condition is raised
+otherwise."
+ (let* ((guix-channel (find guix-channel? channels))
+ (checkout commit relation (update-cached-checkout
+ (channel-url guix-channel)
+ #:ref (or ref '())
+ #:starting-commit
+ %oldest-possible-commit)))
+ (unless (memq relation '(ancestor self))
+ (raise (formatted-message
+ (G_ "cannot travel past commit `~a' from May 1st, 2019")
+ (string-take %oldest-possible-commit 12))))))
+
(when command-line
(let* ((directory
(with-store store
@@ -153,6 +183,8 @@ Execute COMMAND ARGS... in an older version of Guix.\n"))
#:dry-run? #f)
(set-build-options-from-command-line store opts)
(cached-channel-instance store channels
- #:authenticate?
authenticate?)))))
+ #:authenticate? authenticate?
+ #:validate-channels
+ validate-guix-channel)))))
(executable (string-append directory "/bin/guix")))
(apply execl (cons* executable executable command-line))))))))
diff --git a/tests/guix-time-machine.sh b/tests/guix-time-machine.sh
new file mode 100644
index 0000000000..8b62ef75ea
--- /dev/null
+++ b/tests/guix-time-machine.sh
@@ -0,0 +1,28 @@
+# GNU Guix --- Functional package management for GNU
+# Copyright © 2023 Maxim Cournoyer <maxim.cournoyer@gmail.com>
+#
+# This file is part of GNU Guix.
+#
+# GNU Guix is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or (at
+# your option) any later version.
+#
+# GNU Guix is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
+
+#
+# Test the 'guix time-machine' command-line utility.
+#
+
+guix time-machine --version
+
+# Visiting a commit older than v1.0.0 fails.
+! guix time-machine --commit=v0.15.0
+
+exit 0