536 lines
21 KiB
Scheme
536 lines
21 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2017, 2020 Mathieu Othacehe <m.othacehe@gmail.com>
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;;; Copyright © 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (guix git)
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#:use-module (git)
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#:use-module (git object)
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#:use-module (guix i18n)
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#:use-module (guix base32)
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#:use-module (gcrypt hash)
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#:use-module ((guix build utils) #:select (mkdir-p))
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#:use-module (guix store)
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#:use-module (guix utils)
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#:use-module (guix records)
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#:use-module (guix gexp)
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#:use-module (guix sets)
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#:use-module ((guix diagnostics) #:select (leave))
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#:use-module (rnrs bytevectors)
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#:use-module (ice-9 match)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-11)
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#:use-module (srfi srfi-34)
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#:use-module (srfi srfi-35)
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#:export (%repository-cache-directory
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honor-system-x509-certificates!
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with-repository
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with-git-error-handling
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false-if-git-not-found
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update-cached-checkout
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url+commit->name
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latest-repository-commit
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commit-difference
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commit-relation
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git-checkout
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git-checkout?
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git-checkout-url
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git-checkout-branch
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git-checkout-commit
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git-checkout-recursive?))
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(define %repository-cache-directory
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(make-parameter (string-append (cache-directory #:ensure? #f)
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"/checkouts")))
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(define (honor-system-x509-certificates!)
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"Use the system's X.509 certificates for Git checkouts over HTTPS. Honor
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the 'SSL_CERT_FILE' and 'SSL_CERT_DIR' environment variables."
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;; On distros such as CentOS 7, /etc/ssl/certs contains only a couple of
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;; files (instead of all the certificates) among which "ca-bundle.crt". On
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;; other distros /etc/ssl/certs usually contains the whole set of
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;; certificates along with "ca-certificates.crt". Try to choose the right
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;; one.
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(let ((file (letrec-syntax ((choose
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(syntax-rules ()
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((_ file rest ...)
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(let ((f file))
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(if (and f (file-exists? f))
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f
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(choose rest ...))))
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((_)
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#f))))
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(choose (getenv "SSL_CERT_FILE")
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"/etc/ssl/certs/ca-certificates.crt"
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"/etc/ssl/certs/ca-bundle.crt")))
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(directory (or (getenv "SSL_CERT_DIR") "/etc/ssl/certs")))
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(and (or file
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(and=> (stat directory #f)
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(lambda (st)
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(> (stat:nlink st) 2))))
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(begin
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(set-tls-certificate-locations! directory file)
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#t))))
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(define %certificates-initialized?
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;; Whether 'honor-system-x509-certificates!' has already been called.
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#f)
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(define-syntax-rule (with-libgit2 thunk ...)
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(begin
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;; XXX: The right thing to do would be to call (libgit2-shutdown) here,
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;; but pointer finalizers used in guile-git may be called after shutdown,
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;; resulting in a segfault. Hence, let's skip shutdown call for now.
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(libgit2-init!)
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(unless %certificates-initialized?
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(honor-system-x509-certificates!)
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(set! %certificates-initialized? #t))
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thunk ...))
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(define* (url-cache-directory url
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#:optional (cache-directory
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(%repository-cache-directory))
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#:key recursive?)
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"Return the directory associated to URL in %repository-cache-directory."
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(string-append
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cache-directory "/"
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(bytevector->base32-string
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(sha256 (string->utf8 (if recursive?
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(string-append "R:" url)
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url))))))
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;; Authentication appeared in Guile-Git 0.3.0, check if it is available.
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(define auth-supported?
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(false-if-exception (resolve-interface '(git auth))))
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(define (clone* url directory)
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"Clone git repository at URL into DIRECTORY. Upon failure,
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make sure no empty directory is left behind."
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(with-throw-handler #t
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(lambda ()
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(mkdir-p directory)
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;; Note: Explicitly pass options to work around the invalid default
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;; value in Guile-Git: <https://bugs.gnu.org/29238>.
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(if (module-defined? (resolve-interface '(git))
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'clone-init-options)
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(let ((auth-method (and auth-supported?
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(%make-auth-ssh-agent))))
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(clone url directory
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(if auth-supported?
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(make-clone-options
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#:fetch-options (make-fetch-options auth-method))
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(clone-init-options))))
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(clone url directory)))
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(lambda _
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(false-if-exception (rmdir directory)))))
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(define (url+commit->name url sha1)
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"Return the string \"<REPO-NAME>-<SHA1:7>\" where REPO-NAME is the name of
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the git repository, extracted from URL and SHA1:7 the seven first digits
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of SHA1 string."
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(string-append
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(string-replace-substring
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(last (string-split url #\/)) ".git" "")
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"-" (string-take sha1 7)))
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(define (resolve-reference repository ref)
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"Resolve the branch, commit or tag specified by REF, and return the
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corresponding Git object."
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(let resolve ((ref ref))
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(match ref
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(('branch . branch)
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(let ((oid (reference-target
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(branch-lookup repository branch BRANCH-REMOTE))))
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(object-lookup repository oid)))
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(('commit . commit)
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(let ((len (string-length commit)))
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;; 'object-lookup-prefix' appeared in Guile-Git in Mar. 2018, so we
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;; can't be sure it's available. Furthermore, 'string->oid' used to
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;; read out-of-bounds when passed a string shorter than 40 chars,
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;; which is why we delay calls to it below.
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(if (< len 40)
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(if (module-defined? (resolve-interface '(git object))
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'object-lookup-prefix)
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(object-lookup-prefix repository (string->oid commit) len)
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(raise (condition
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(&message
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(message "long Git object ID is required")))))
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(object-lookup repository (string->oid commit)))))
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(('tag-or-commit . str)
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(if (or (> (string-length str) 40)
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(not (string-every char-set:hex-digit str)))
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(resolve `(tag . ,str)) ;definitely a tag
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(catch 'git-error
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(lambda ()
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(resolve `(tag . ,str)))
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(lambda _
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;; There's no such tag, so it must be a commit ID.
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(resolve `(commit . ,str))))))
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(('tag . tag)
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(let ((oid (reference-name->oid repository
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(string-append "refs/tags/" tag))))
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;; OID may point to a "tag" object, but it can also point directly
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;; to a "commit" object, as surprising as it may seem. Return that
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;; object, whatever that is.
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(object-lookup repository oid))))))
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(define (switch-to-ref repository ref)
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"Switch to REPOSITORY's branch, commit or tag specified by REF. Return the
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OID (roughly the commit hash) corresponding to REF."
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(define obj
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(resolve-reference repository ref))
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(reset repository obj RESET_HARD)
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(object-id obj))
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(define (call-with-repository directory proc)
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(let ((repository #f))
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(dynamic-wind
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(lambda ()
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(set! repository (repository-open directory)))
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(lambda ()
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(proc repository))
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(lambda ()
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(repository-close! repository)))))
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(define-syntax-rule (with-repository directory repository exp ...)
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"Open the repository at DIRECTORY and bind REPOSITORY to it within the
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dynamic extent of EXP."
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(call-with-repository directory
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(lambda (repository) exp ...)))
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(define (report-git-error error)
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"Report the given Guile-Git error."
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;; Prior to Guile-Git commit b6b2760c2fd6dfaa5c0fedb43eeaff06166b3134,
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;; errors would be represented by integers.
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(match error
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((? integer? error) ;old Guile-Git
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(leave (G_ "Git error ~a~%") error))
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((? git-error? error) ;new Guile-Git
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(leave (G_ "Git error: ~a~%") (git-error-message error)))))
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(define-syntax-rule (with-git-error-handling body ...)
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(catch 'git-error
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(lambda ()
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body ...)
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(lambda (key err)
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(report-git-error err))))
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(define (load-git-submodules)
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"Attempt to load (git submodules), which was missing until Guile-Git 0.2.0.
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Return true on success, false on failure."
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(match (false-if-exception (resolve-interface '(git submodule)))
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(#f
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(set! load-git-submodules (const #f))
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#f)
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(iface
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(module-use! (resolve-module '(guix git)) iface)
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(set! load-git-submodules (const #t))
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#t)))
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(define* (update-submodules repository
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#:key (log-port (current-error-port)))
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"Update the submodules of REPOSITORY, a Git repository object."
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;; Guile-Git < 0.2.0 did not have (git submodule).
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(if (load-git-submodules)
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(for-each (lambda (name)
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(let ((submodule (submodule-lookup repository name)))
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(format log-port (G_ "updating submodule '~a'...~%")
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name)
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(submodule-update submodule)
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;; Recurse in SUBMODULE.
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(let ((directory (string-append
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(repository-working-directory repository)
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"/" (submodule-path submodule))))
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(with-repository directory repository
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(update-submodules repository
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#:log-port log-port)))))
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(repository-submodules repository))
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(format (current-error-port)
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(G_ "Support for submodules is missing; \
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please upgrade Guile-Git.~%"))))
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(define-syntax-rule (false-if-git-not-found exp)
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"Evaluate EXP, returning #false if a GIT_ENOTFOUND error is raised."
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(catch 'git-error
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(lambda ()
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exp)
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(lambda (key error . rest)
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(if (= GIT_ENOTFOUND (git-error-code error))
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#f
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(apply throw key error rest)))))
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(define (reference-available? repository ref)
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"Return true if REF, a reference such as '(commit . \"cabba9e\"), is
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definitely available in REPOSITORY, false otherwise."
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(match ref
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(('commit . commit)
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(false-if-git-not-found
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(->bool (commit-lookup repository (string->oid commit)))))
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(_
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#f)))
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(define* (update-cached-checkout url
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#:key
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(ref '(branch . "master"))
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recursive?
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(check-out? #t)
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starting-commit
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(log-port (%make-void-port "w"))
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(cache-directory
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(url-cache-directory
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url (%repository-cache-directory)
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#:recursive? recursive?)))
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"Update the cached checkout of URL to REF in CACHE-DIRECTORY. Return three
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values: the cache directory name, and the SHA1 commit (a string) corresponding
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to REF, and the relation of the new commit relative to STARTING-COMMIT (if
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provided) as returned by 'commit-relation'.
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REF is pair whose key is [branch | commit | tag | tag-or-commit ] and value
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the associated data: [<branch name> | <sha1> | <tag name> | <string>].
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When RECURSIVE? is true, check out submodules as well, if any.
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When CHECK-OUT? is true, reset the cached working tree to REF; otherwise leave
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it unchanged."
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(define canonical-ref
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;; We used to require callers to specify "origin/" for each branch, which
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;; made little sense since the cache should be transparent to them. So
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;; here we append "origin/" if it's missing and otherwise keep it.
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(match ref
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(('branch . branch)
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`(branch . ,(if (string-prefix? "origin/" branch)
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branch
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(string-append "origin/" branch))))
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(_ ref)))
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(with-libgit2
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(let* ((cache-exists? (openable-repository? cache-directory))
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(repository (if cache-exists?
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(repository-open cache-directory)
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(clone* url cache-directory))))
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;; Only fetch remote if it has not been cloned just before.
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(when (and cache-exists?
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(not (reference-available? repository ref)))
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(if auth-supported?
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(let ((auth-method (and auth-supported?
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(%make-auth-ssh-agent))))
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(remote-fetch (remote-lookup repository "origin")
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#:fetch-options (make-fetch-options auth-method)))
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(remote-fetch (remote-lookup repository "origin"))))
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(when recursive?
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(update-submodules repository #:log-port log-port))
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;; Note: call 'commit-relation' from here because it's more efficient
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;; than letting users re-open the checkout later on.
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(let* ((oid (if check-out?
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(switch-to-ref repository canonical-ref)
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(object-id
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(resolve-reference repository canonical-ref))))
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(new (and starting-commit
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(commit-lookup repository oid)))
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(old (and starting-commit
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(false-if-git-not-found
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(commit-lookup repository
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(string->oid starting-commit)))))
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(relation (and starting-commit
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(if old
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(commit-relation old new)
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'unrelated))))
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;; Reclaim file descriptors and memory mappings associated with
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;; REPOSITORY as soon as possible.
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(when (module-defined? (resolve-interface '(git repository))
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'repository-close!)
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(repository-close! repository))
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(values cache-directory (oid->string oid) relation)))))
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(define* (latest-repository-commit store url
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#:key
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recursive?
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(log-port (%make-void-port "w"))
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(cache-directory
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(%repository-cache-directory))
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(ref '(branch . "master")))
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"Return two values: the content of the git repository at URL copied into a
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store directory and the sha1 of the top level commit in this directory. The
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reference to be checkout, once the repository is fetched, is specified by REF.
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REF is pair whose key is [branch | commit | tag] and value the associated
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data, respectively [<branch name> | <sha1> | <tag name>].
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When RECURSIVE? is true, check out submodules as well, if any.
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Git repositories are kept in the cache directory specified by
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%repository-cache-directory parameter.
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Log progress and checkout info to LOG-PORT."
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(define (dot-git? file stat)
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(and (string=? (basename file) ".git")
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(or (eq? 'directory (stat:type stat))
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;; Submodule checkouts end up with a '.git' regular file that
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;; contains metadata about where their actual '.git' directory
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;; lives.
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(and recursive?
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(eq? 'regular (stat:type stat))))))
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(format log-port "updating checkout of '~a'...~%" url)
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(let*-values
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(((checkout commit _)
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(update-cached-checkout url
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#:recursive? recursive?
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#:ref ref
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#:cache-directory
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(url-cache-directory url cache-directory
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#:recursive?
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recursive?)
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#:log-port log-port))
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((name)
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(url+commit->name url commit)))
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(format log-port "retrieved commit ~a~%" commit)
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(values (add-to-store store name #t "sha256" checkout
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#:select? (negate dot-git?))
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commit)))
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(define (print-git-error port key args default-printer)
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(match args
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(((? git-error? error) . _)
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(format port (G_ "Git error: ~a~%")
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(git-error-message error)))))
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(set-exception-printer! 'git-error print-git-error)
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;;;
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;;; Commit difference.
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;;;
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(define* (commit-closure commit #:optional (visited (setq)))
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"Return the closure of COMMIT as a set. Skip commits contained in VISITED,
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a set, and adjoin VISITED to the result."
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(let loop ((commits (list commit))
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(visited visited))
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(match commits
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(()
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visited)
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((head . tail)
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(if (set-contains? visited head)
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(loop tail visited)
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(loop (append (commit-parents head) tail)
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(set-insert head visited)))))))
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(define* (commit-difference new old #:optional (excluded '()))
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"Return the list of commits between NEW and OLD, where OLD is assumed to be
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an ancestor of NEW. Exclude all the commits listed in EXCLUDED along with
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their ancestors.
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Essentially, this computes the set difference between the closure of NEW and
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that of OLD."
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(let loop ((commits (list new))
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(result '())
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(visited (fold commit-closure
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(setq)
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(cons old excluded))))
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(match commits
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(()
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(reverse result))
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((head . tail)
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(if (set-contains? visited head)
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(loop tail result visited)
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(loop (append (commit-parents head) tail)
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(cons head result)
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(set-insert head visited)))))))
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(define (commit-relation old new)
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"Return a symbol denoting the relation between OLD and NEW, two commit
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objects: 'ancestor (meaning that OLD is an ancestor of NEW), 'descendant, or
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'unrelated, or 'self (OLD and NEW are the same commit)."
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(if (eq? old new)
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'self
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(let ((newest (commit-closure new)))
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(if (set-contains? newest old)
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'ancestor
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(let* ((seen (list->setq (commit-parents new)))
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(oldest (commit-closure old seen)))
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(if (set-contains? oldest new)
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'descendant
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'unrelated))))))
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;;;
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;;; Checkouts.
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;;;
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;; Representation of the "latest" checkout of a branch or a specific commit.
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(define-record-type* <git-checkout>
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git-checkout make-git-checkout
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git-checkout?
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(url git-checkout-url)
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(branch git-checkout-branch (default "master"))
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(commit git-checkout-commit (default #f)) ;#f | tag | commit
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(recursive? git-checkout-recursive? (default #f)))
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(define* (latest-repository-commit* url #:key ref recursive? log-port)
|
||
;; Monadic variant of 'latest-repository-commit'.
|
||
(lambda (store)
|
||
;; The caller--e.g., (guix scripts build)--may not handle 'git-error' so
|
||
;; translate it into '&message' conditions that we know will be properly
|
||
;; handled.
|
||
(catch 'git-error
|
||
(lambda ()
|
||
(values (latest-repository-commit store url
|
||
#:ref ref
|
||
#:recursive? recursive?
|
||
#:log-port log-port)
|
||
store))
|
||
(lambda (key error . _)
|
||
(raise (condition
|
||
(&message
|
||
(message
|
||
(match ref
|
||
(('commit . commit)
|
||
(format #f (G_ "cannot fetch commit ~a from ~a: ~a")
|
||
commit url (git-error-message error)))
|
||
(('branch . branch)
|
||
(format #f (G_ "cannot fetch branch '~a' from ~a: ~a")
|
||
branch url (git-error-message error)))
|
||
(_
|
||
(format #f (G_ "Git failure while fetching ~a: ~a")
|
||
url (git-error-message error))))))))))))
|
||
|
||
(define-gexp-compiler (git-checkout-compiler (checkout <git-checkout>)
|
||
system target)
|
||
;; "Compile" CHECKOUT by updating the local checkout and adding it to the
|
||
;; store.
|
||
(match checkout
|
||
(($ <git-checkout> url branch commit recursive?)
|
||
(latest-repository-commit* url
|
||
#:ref (if commit
|
||
`(tag-or-commit . ,commit)
|
||
`(branch . ,branch))
|
||
#:recursive? recursive?
|
||
#:log-port (current-error-port)))))
|
||
|
||
;; Local Variables:
|
||
;; eval: (put 'with-repository 'scheme-indent-function 2)
|
||
;; End:
|