From f924dbb835425f6b9a5796918125592870391405 Mon Sep 17 00:00:00 2001
Message-Id: <f924dbb835425f6b9a5796918125592870391405.1631125652.git.public@yoctocell.xyz>
From: Xinglu Chen <public@yoctocell.xyz>
Date: Fri, 3 Sep 2021 17:50:56 +0200
Subject: [PATCH] import: Add 'generic-git' updater.

* guix/import/git.scm: New file.
* doc/guix.texi (Invoking guix refresh): Document it.
* Makefile.am (MODULES): Register it.
* guix/git.scm (ls-remote-refs): New procedure.

Co-authored-by: Sarah Morgensen <iskarian@mgsn.dev>
---
 Makefile.am         |   1 +
 doc/guix.texi       |  27 ++++++
 guix/git.scm        |  33 +++++++
 guix/import/git.scm | 217 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 278 insertions(+)
 create mode 100644 guix/import/git.scm

diff --git a/Makefile.am b/Makefile.am
index 3c79760734..c4d3a456b1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -254,6 +254,7 @@ MODULES =					\
   guix/import/egg.scm   			\
   guix/import/elpa.scm   			\
   guix/import/gem.scm				\
+  guix/import/git.scm                           \
   guix/import/github.scm   			\
   guix/import/gnome.scm				\
   guix/import/gnu.scm				\
diff --git a/doc/guix.texi b/doc/guix.texi
index 36a0c7f5ec..26afb1607a 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -11920,6 +11920,33 @@ the updater for @uref{https://launchpad.net, Launchpad} packages.
 @item generic-html
 a generic updater that crawls the HTML page where the source tarball of
 the package is hosted, when applicable.
+@item generic-git
+a generic updater for packages hosted on Git repositories.  It tries to
+be smart about parsing Git tag names, but if it is not able to parse the
+tag name and compare tags correctly, users can define the following
+properties for a package.
+
+@itemize
+@item @code{tag-prefix}: a regular expression for matching a prefix of
+the tag name.
+
+@item @code{tag-suffix}: a regular expression for matching a suffix of
+the tag name.
+
+@item @code{tag-version-delimiter}: a string used as the delimiter in
+the tag name for separating the numbers of the version.
+@end itemize
+
+@lisp
+(package
+  (name "foo")
+  ;; ...
+  (properties
+    '((tag-prefix . "^release0-")
+      (tag-suffix . "[a-z]?$")
+      (tag-version-delimiter . ":"))))
+@end lisp      
+
 @end table
 
 For instance, the following command only checks for updates of Emacs
diff --git a/guix/git.scm b/guix/git.scm
index 9c6f326c36..c5d0d2da8e 100644
--- a/guix/git.scm
+++ b/guix/git.scm
@@ -56,6 +56,8 @@
             commit-difference
             commit-relation
 
+            ls-remote-refs
+
             git-checkout
             git-checkout?
             git-checkout-url
@@ -556,6 +558,37 @@ objects: 'ancestor (meaning that OLD is an ancestor of NEW), 'descendant, or
               (if (set-contains? oldest new)
                   'descendant
                   'unrelated))))))
+
+;;
+;;; Remote operations.
+;;;
+
+(define* (ls-remote-refs url #:key tags?)
+  "Return the list of references advertised at Git repository URL.  If TAGS?
+is true, limit to only refs/tags."
+  (define (ref? ref)
+    ;; Like `git ls-remote --refs', only show actual references.
+    (and (string-prefix? "refs/" ref)
+         (not (string-suffix? "^{}" ref))))
+
+  (define (tag? ref)
+    (string-prefix? "refs/tags/" ref))
+
+  (define (include? ref)
+    (and (ref? ref)
+         (or (not tags?) (tag? ref))))
+
+  (with-libgit2
+   (call-with-temporary-directory
+    (lambda (cache-directory)
+      (let* ((repository (repository-init cache-directory))
+             ;; Create an in-memory remote so we don't touch disk.
+             (remote (remote-create-anonymous repository url)))
+        (remote-connect remote)
+        (remote-disconnect remote)
+        (repository-close! repository)
+
+        (filter include? (map remote-head-name (remote-ls remote))))))))
 
 
 ;;;
diff --git a/guix/import/git.scm b/guix/import/git.scm
new file mode 100644
index 0000000000..52c98de197
--- /dev/null
+++ b/guix/import/git.scm
@@ -0,0 +1,217 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
+;;; Copyright © 2021 Sarah Morgensen <iskarian@mgsn.dev>
+;;;
+;;; 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/>.
+
+(define-module (guix import git)
+  #:use-module (guix build utils)
+  #:use-module (guix diagnostics)
+  #:use-module (guix git)
+  #:use-module (guix git-download)
+  #:use-module (guix i18n)
+  #:use-module (guix packages)
+  #:use-module (guix upstream)
+  #:use-module (guix utils)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 rdelim)
+  #:use-module (ice-9 regex)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-35)
+  #:export (%generic-git-updater))
+
+;;; Commentary:
+;;;
+;;; This module provides a generic package updater for packages hosted on Git
+;;; repositories.
+;;;
+;;; It tries to be smart about tag names, but if it is not automatically able
+;;; to parse the tag names correctly, users can set the `tag-prefix',
+;;; `tag-suffix' and `tag-version-delimiter' properties of the package to make
+;;; the updater parse the Git tag name correctly.
+;;;
+;;; Code:
+
+;;; Errors & warnings
+
+(define-condition-type &git-no-valid-tags-error &error
+  git-no-valid-tags-error?)
+
+(define (git-no-valid-tags-error)
+  (raise (condition (&message (message "no valid tags found"))
+                    (&git-no-valid-tags-error))))
+
+(define-condition-type &git-no-tags-error &error
+  git-no-tags-error?)
+
+(define (git-no-tags-error)
+  (raise (condition (&message (message "no tags were found"))
+                    (&git-no-tags-error))))
+
+
+;;; Updater
+
+(define %pre-release-words
+  '("alpha" "beta" "rc" "dev" "test"))
+
+(define* (get-version-mapping tags #:key prefix suffix delim pre-releases?)
+  (define (guess-delim)
+    (let ((total (length tags))
+          (dots (reduce + 0 (map (cut string-count <> #\.) tags)))
+          (dashes (reduce + 0 (map (cut string-count <> #\-) tags)))
+          (underscores (reduce + 0 (map (cut string-count <> #\_) tags))))
+      (display (format #t "total: ~d, dots: ~d, dashes ~d, underscores ~d~%"
+              total dots dashes underscores))
+      (cond
+       ((>= dots (* total 0.35)) ".")
+       ((>= dashes (* total 0.8)) "-")
+       ((>= underscores (* total 0.8)) "_")
+       (else ""))))
+
+  (define delim-rx (regexp-quote (or delim (guess-delim))))
+  (define suffix-rx
+    (string-append
+     (or suffix
+         (if pre-releases?
+             (string-append ".*(" (string-join %pre-release-words "|") ").*")
+             ""))
+     "$"))
+  
+  (define prefix-rx (string-append "^" (or prefix "[^[:digit:]]*")))
+  (pk delim-rx)
+
+  (define tag-rx
+     (string-append "([[:digit:]][^" delim-rx "[:punct:]]*"
+                    "(" delim-rx "[^[:punct:]" delim-rx "]+)"
+                    ;; If there is are no delimiters, it could mean that the
+                    ;; version just contains one number (e.g., "2"), thus, use
+                    ;; "*" instead of "+" to match zero or more numbers.
+                    (if (string=? delim-rx "") "*" "+")
+                    ")" suffix-rx))
+
+  (define (get-version tag)
+    (let ((tag-match (regexp-exec (make-regexp tag-rx) tag)))
+      (pk tag)
+      (pk tag-match)
+      (pk tag-rx)
+      (and tag-match
+           (regexp-exec (make-regexp prefix-rx) (match:prefix tag-match))
+           (regexp-substitute/global
+            #f delim-rx (match:substring tag-match)
+            ;; Don't insert "." if there aren't any delimiters in the first
+            ;; place.
+            'pre (if (string=? delim-rx "") "" ".") 'post))))
+
+  (define (entry<? a b)
+    (eq? (version-compare (car a) (car b)) '<))
+
+  (let ((mapping (fold alist-cons '() (map get-version tags) tags)))
+    (stable-sort! (filter car mapping) entry<?)))
+
+(define* (get-latest-tag url #:key prefix suffix delim pre-releases?)
+  "Return the latest tag available from the Git repository at URL."
+  (define (pre-release? tag)
+    (any (lambda (rx) (regexp-exec (make-regexp rx regexp/icase) tag))
+              %pre-release-words))
+
+  (let* ((tags (map (cut string-drop <> (string-length "refs/tags/"))
+                    (ls-remote-refs url #:tags? #t)))
+         (versions->tags
+          (get-version-mapping (if pre-releases?
+                                   tags
+                                   (filter (negate pre-release?) tags))
+                               #:prefix prefix
+                               #:suffix suffix
+                               #:delim delim
+                               #:pre-releases? pre-releases?)))
+    (display versions->tags)
+    (newline)
+    (cond
+     ((null? tags)
+      (git-no-tags-error))
+     ((null? versions->tags)
+      (git-no-valid-tags-error))
+     (else
+      (match (last versions->tags)
+        ((version . tag)
+         (values version tag)))))))
+
+(define (latest-git-tag-version package tag-prefix tag-suffix
+                                tag-version-delimiter refresh-pre-releases?)
+  "Given a PACKAGE, the TAG-PREFIX, TAG-SUFFIX, TAG-VERSION-DELIMITER, and
+REFRESH-PRE-RELEASES?  properties of PACKAGE, returns the latest version of
+PACKAGE."
+  (guard (c ((or (git-no-tags-error? c) (git-no-valid-tags-error? c))
+             (warning (or (package-field-location package 'source)
+                          (package-location package))
+                      (G_ "~a for ~a~%")
+                      (condition-message c)
+                      (package-name package))
+             #f)
+            ((eq? (exception-kind c) 'git-error)
+             (warning (or (package-field-location package 'source)
+                          (package-location package))
+                      (G_ "failed to fetch Git repository for ~a~%")
+                      (package-name package))
+             #f))
+    (let* ((source (package-source package))
+           (url (git-reference-url (origin-uri source))))
+      ;;(format #t "~a~%" (package-name package))
+      (get-latest-tag url #:prefix tag-prefix #:suffix tag-suffix
+                      #:delim tag-version-delimiter
+                      #:pre-releases? refresh-pre-releases?))))
+
+(define (git-package? package)
+  "Whether the origin of PACKAGE is a Git repostiory."
+  (match (package-source package)
+    ((? origin? origin)
+     (and (eq? (origin-method origin) git-fetch)
+          (git-reference? (origin-uri origin))))
+    (_ #f)))
+
+(define (latest-git-release package)
+  "Return the latest release of PACKAGE."
+  (let* ((name (package-name package))
+         (properties (package-properties package))
+         (tag-prefix (assq-ref properties 'tag-prefix))
+         (tag-suffix (assq-ref properties 'tag-suffix))
+         (tag-version-delimiter (assq-ref properties 'tag-version-delimiter))
+         (refresh-pre-releases? (assq-ref properties 'refresh-pre-releases?))
+         (old-version (package-version package))
+         (url (git-reference-url (origin-uri (package-source package))))
+         (new-version (latest-git-tag-version package
+                                              tag-prefix
+                                              tag-suffix
+                                              tag-version-delimiter
+                                              refresh-pre-releases?)))
+
+    (if new-version
+        (upstream-source
+         (package name)
+         (version new-version)
+         (urls (list url)))
+        ;; No new release or no tags available.
+        #f)))
+
+(define %generic-git-updater
+  (upstream-updater
+   (name 'generic-git)
+   (description "Updater for packages hosted on Git repositories")
+   (pred git-package?)
+   (latest latest-git-release)))
-- 
2.33.0

