Add (guix self) and use it when pulling.

This mitigates <https://bugs.gnu.org/27284>.

* guix/self.scm: New file.
* Makefile.am (MODULES): Add it.
* build-aux/build-self.scm (libgcrypt, zlib, gzip, bzip2, xz)
(false-if-wrong-guile, package-for-current-guile, guile-json)
(guile-ssh, guile-git, guile-bytestructures): Remove.
(build): Rewrite to simply delegate to 'compiled-guix'.
* gnu/packages.scm (%distro-root-directory): Rewrite to try different
directories.
* guix/discovery.scm (guix): Export 'scheme-files'.
* guix/scripts/pull.scm (build-and-install): Split into...
(install-latest): ... this.  New procedure.  And...
(build-and-install): ... this, which now takes a monadic value argument.
(indirect-root-added): Remove.
(guix-pull): Call 'add-indirect-root'.  Call 'build-from-source' and
pass the result to 'build-and-install'.

1 files changed, 55 insertions, 213 deletions

diff --git a/build-aux/build-self.scm b/build-aux/build-self.scm
index ed8ff5f4ce..d9d9263678 100644
--- a/build-aux/build-self.scm
+++ b/build-aux/build-self.scm
@@ -17,11 +17,9 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (build-self)
-  #:use-module (gnu)
-  #:use-module (guix)
-  #:use-module (guix config)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-19)
+  #:use-module (srfi srfi-26)
   #:use-module (ice-9 match)
   #:export (build))
 
@@ -31,105 +29,51 @@
 ;;; argument: the source tree to build.  It returns a derivation that
 ;;; builds it.
 ;;;
-;;; This file uses modules provided by the already-installed Guix.  Those
-;;; modules may be arbitrarily old compared to the version we want to
-;;; build.  Because of that, it must rely on the smallest set of features
-;;; that are likely to be provided by the (guix) and (gnu) modules, and by
-;;; Guile itself, forever and ever.
-;;;
 ;;; Code:
 
-
-;; The dependencies.  Don't refer explicitly to the variables because they
-;; could be renamed or shuffled around in modules over time.  Conversely,
-;; 'find-best-packages-by-name' is expected to always have the same semantics.
-
-(define libgcrypt
-  (first (find-best-packages-by-name "libgcrypt" #f)))
-
-(define zlib
-  (first (find-best-packages-by-name "zlib" #f)))
-
-(define gzip
-  (first (find-best-packages-by-name "gzip" #f)))
-
-(define bzip2
-  (first (find-best-packages-by-name "bzip2" #f)))
-
-(define xz
-  (first (find-best-packages-by-name "xz" #f)))
-
-(define (false-if-wrong-guile package)
-  "Return #f if PACKAGE depends on the \"wrong\" major version of Guile (e.g.,
-2.0 instead of 2.2), otherwise return PACKAGE."
-  (let ((guile (any (match-lambda
-                      ((label (? package? dep) _ ...)
-                       (and (string=? (package-name dep) "guile")
-                            dep)))
-                    (package-direct-inputs package))))
-    (and (or (not guile)
-             (string-prefix? (effective-version)
-                             (package-version guile)))
-         package)))
-
-(define (package-for-current-guile . names)
-  "Return the package with one of the given NAMES that depends on the current
-Guile major version (2.0 or 2.2), or #f if none of the packages matches."
-  (let loop ((names names))
-    (match names
-      (()
-       #f)
-      ((name rest ...)
-       (match (find-best-packages-by-name name #f)
-         (()
-          (loop rest))
-         ((first _ ...)
-          (or (false-if-wrong-guile first)
-              (loop rest))))))))
-
-(define guile-json
-  (package-for-current-guile "guile-json"
-                             "guile2.2-json"
-                             "guile2.0-json"))
-
-(define guile-ssh
-  (package-for-current-guile "guile-ssh"
-                             "guile2.2-ssh"
-                             "guile2.0-ssh"))
-
-(define guile-git
-  (package-for-current-guile "guile-git"
-                             "guile2.0-git"))
-
-(define guile-bytestructures
-  (package-for-current-guile "guile-bytestructures"
-                             "guile2.0-bytestructures"))
-
-;; The actual build procedure.
-
-(define (top-source-directory)
-  "Return the name of the top-level directory of this source tree."
+;; Use our very own Guix modules.
+(eval-when (compile load eval)
   (and=> (assoc-ref (current-source-location) 'filename)
          (lambda (file)
-           (string-append (dirname file) "/.."))))
-
+           (let ((dir (string-append (dirname file) "/..")))
+             (set! %load-path (cons dir %load-path))))))
 
 (define (date-version-string)
   "Return the current date and hour in UTC timezone, for use as a poor
 person's version identifier."
-  ;; XXX: Replace with a Git commit id.
+  ;; XXX: Last resort when the Git commit id is missing.
   (date->string (current-date 0) "~Y~m~d.~H"))
 
-(define (guile-for-build)
-  "Return a derivation for Guile 2.0 or 2.2, whichever matches the currently
-running Guile."
-  (package->derivation (cond-expand
-                         (guile-2.2
-                          (canonical-package
-                           (specification->package "guile@2.2")))
-                         (else
-                          (canonical-package
-                           (specification->package "guile@2.0"))))))
+(define-syntax parameterize*
+  (syntax-rules ()
+    "Like 'parameterize' but for regular variables (!)."
+    ((_ ((var value) rest ...) body ...)
+     (let ((old var)
+           (new value))
+       (dynamic-wind
+         (lambda ()
+           (set! var new))
+         (lambda ()
+           (parameterize* (rest ...) body ...))
+         (lambda ()
+           (set! var old)))))
+    ((_ () body ...)
+     (begin body ...))))
+
+(define (pure-load-compiled-path)
+  "Return %LOAD-COMPILED-PATH minus the directories containing .go files from
+Guix."
+  (define (purify path)
+    (fold-right delete path
+                (filter-map (lambda (file)
+                              (and=> (search-path path file) dirname))
+                            '("guix.go" "gnu.go"))))
+
+  (let loop ((path %load-compiled-path))
+    (let ((next (purify path)))
+      (if (equal? next path)
+          path
+          (loop next)))))
 
 ;; The procedure below is our return value.
 (define* (build source
@@ -138,131 +82,29 @@ running Guile."
                 #:rest rest)
   "Return a derivation that unpacks SOURCE into STORE and compiles Scheme
 files."
-  ;; The '%xxxdir' variables were added to (guix config) in July 2016 so we
-  ;; cannot assume that they are defined.  Try to guess their value when
-  ;; they're undefined (XXX: we get an incorrect guess when environment
-  ;; variables such as 'NIX_STATE_DIR' are defined!).
-  (define storedir
-    (if (defined? '%storedir) %storedir %store-directory))
-  (define localstatedir
-    (if (defined? '%localstatedir) %localstatedir (dirname %state-directory)))
-  (define sysconfdir
-    (if (defined? '%sysconfdir) %sysconfdir (dirname %config-directory)))
-  (define sbindir
-    (if (defined? '%sbindir) %sbindir (dirname %guix-register-program)))
-
-  (define builder
-    #~(begin
-        (use-modules (guix build pull))
-
-        (letrec-syntax ((maybe-load-path
-                         (syntax-rules ()
-                           ((_ item rest ...)
-                            (let ((tail (maybe-load-path rest ...)))
-                              (if (string? item)
-                                  (cons (string-append item
-                                                       "/share/guile/site/"
-                                                       #$(effective-version))
-                                        tail)
-                                  tail)))
-                           ((_)
-                            '()))))
-          (set! %load-path
-                (append
-                 (maybe-load-path #$guile-json #$guile-ssh
-                                  #$guile-git #$guile-bytestructures)
-                 %load-path)))
-
-        (letrec-syntax ((maybe-load-compiled-path
-                         (syntax-rules ()
-                           ((_ item rest ...)
-                            (let ((tail (maybe-load-compiled-path rest ...)))
-                              (if (string? item)
-                                  (cons (string-append item
-                                                       "/lib/guile/"
-                                                       #$(effective-version)
-                                                       "/site-ccache")
-                                        tail)
-                                  tail)))
-                           ((_)
-                            '()))))
-          (set! %load-compiled-path
-                (append
-                 (maybe-load-compiled-path #$guile-json #$guile-ssh
-                                           #$guile-git #$guile-bytestructures)
-                 %load-compiled-path)))
-
-        ;; XXX: The 'guile-ssh' package prior to Guix commit 92b7258 was
-        ;; broken: libguile-ssh could not be found.  Work around that.
-        ;; FIXME: We want Guile-SSH 0.10.2 or later anyway.
-        #$(if (string-prefix? "0.9." (package-version guile-ssh))
-              #~(setenv "LTDL_LIBRARY_PATH" (string-append #$guile-ssh "/lib"))
-              #t)
-
-        (build-guix #$output #$source
-
-                    #:system #$%system
-                    #:storedir #$storedir
-                    #:localstatedir #$localstatedir
-                    #:sysconfdir #$sysconfdir
-                    #:sbindir #$sbindir
-
-                    #:package-name #$%guix-package-name
-                    #:package-version #$version
-                    #:bug-report-address #$%guix-bug-report-address
-                    #:home-page-url #$%guix-home-page-url
+  ;; Start by jumping into the target Guix so that we have access to the
+  ;; latest packages and APIs.
+  ;;
+  ;; Our checkout in the store has mtime set to the epoch, and thus .go
+  ;; files look newer, even though they may not correspond.
+  (parameterize* ((%load-should-auto-compile #f)
+                  (%fresh-auto-compile #f)
 
-                    #:libgcrypt #$libgcrypt
-                    #:zlib #$zlib
-                    #:gzip #$gzip
-                    #:bzip2 #$bzip2
-                    #:xz #$xz
+                  ;; Work around <https://bugs.gnu.org/29226>.
+                  (%load-compiled-path (pure-load-compiled-path)))
+    ;; FIXME: This is currently too expensive notably because it involves
+    ;; compiling a number of the big package files such as perl.scm, which
+    ;; takes lots of time and memory as of Guile 2.2.2.
+    ;;
+    ;; (let ((reload-guix (module-ref (resolve-interface '(guix self))
+    ;;                                'reload-guix)))
+    ;;   (reload-guix))           ;cross fingers!
 
-                    ;; XXX: This is not perfect, enabling VERBOSE? means
-                    ;; building a different derivation.
-                    #:debug-port (if #$verbose?
-                                     (current-error-port)
-                                     (%make-void-port "w")))))
-
-  (unless guile-git
-    ;; XXX: Guix before February 2017 lacks a 'guile-git' package altogether.
-    ;; If we try to upgrade anyway, the logic in (guix scripts pull) will not
-    ;; build (guix git), which will leave us with an unusable 'guix pull'.  To
-    ;; avoid that, fail early.
-    (format (current-error-port)
-            "\
-Your installation is too old and lacks a '~a' package.
-Please upgrade to an intermediate version first, for instance with:
-
-  guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.13.0.tar.gz
-\n"
-            (match (effective-version)
-              ("2.0" "guile2.0-git")
-              (_     "guile-git")))
-    (exit 1))
-
-  (mlet %store-monad ((guile (guile-for-build)))
-    (gexp->derivation "guix-latest" builder
-                      #:modules '((guix build pull)
-                                  (guix build utils)
-                                  (guix build compile)
-
-                                  ;; Closure of (guix modules).
-                                  (guix modules)
-                                  (guix memoization)
-                                  (guix sets))
-
-                      ;; Arrange so that our own (guix build …) modules are
-                      ;; used.
-                      #:module-path (list (top-source-directory))
-
-                      #:guile-for-build guile)))
+    (let ((guix-derivation (module-ref (resolve-interface '(guix self))
+                                       'guix-derivation)))
+      (guix-derivation source version))))
 
 ;; This file is loaded by 'guix pull'; return it the build procedure.
 build
 
-;; Local Variables:
-;; eval: (put 'with-load-path 'scheme-indent-function 1)
-;; End:
-
 ;;; build-self.scm ends here