import: Remove Nix importer.

This importer has suffered from bitrot and no longer works with current
Nix and Nixpkgs.  See <https://bugs.gnu.org/32339> and
<https://bugs.gnu.org/36255>.

* guix/import/snix.scm, guix/scripts/import/nix.scm,
tests/snix.scm: Remove.
* Makefile.am (MODULES, SCM_TESTS): Remove them.
* guix/scripts/import.scm (importers): Remove "nix".
* build-aux/test-env.in: Remove NIXPKGS variable.
* configure.ac: Remove '--with-nixpkgs' option.
* doc/guix.texi (Invoking guix import): Remove bit about "guix import
nix".
* etc/completion/fish/guix.fish: Likewise.

3 files changed, 2 insertions, 559 deletions

diff --git a/guix/import/snix.scm b/guix/import/snix.scm
deleted file mode 100644
index 56934e8cf9..0000000000
--- a/guix/import/snix.scm
+++ /dev/null
@@ -1,467 +0,0 @@
-;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
-;;;
-;;; 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 snix)
-  #:use-module (sxml ssax)
-  #:use-module (ice-9 popen)
-  #:use-module (ice-9 match)
-  #:use-module (ice-9 rdelim)
-  #:use-module (ice-9 format)
-  #:use-module (ice-9 regex)
-  #:use-module (ice-9 vlist)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-9)
-  #:use-module (srfi srfi-11)
-  #:use-module (srfi srfi-26)
-  #:use-module (srfi srfi-37)
-  #:use-module (system foreign)
-  #:use-module (rnrs bytevectors)
-
-  ;; Use the 'package-name->name+version' procedure that works with
-  ;; hyphen-separate name/version, not the one that works with '@'-separated
-  ;; name/version.  Subtle!
-  #:use-module ((guix utils) #:hide (package-name->name+version))
-  #:use-module ((guix build utils) #:select (package-name->name+version))
-
-  #:use-module (guix import utils)
-  #:use-module (guix base16)
-  #:use-module (guix base32)
-  #:use-module (guix config)
-  #:use-module (guix gnu-maintenance)
-  #:export (open-nixpkgs
-            xml->snix
-            nixpkgs->guix-package))
-
-;;; Commentary:
-;;;
-;;; Converting Nix code to s-expressions, and then to Guix `package'
-;;; declarations, using the XML output of `nix-instantiate'.
-;;;
-;;; Code:
-
-
-;;;
-;;; SNix.
-;;;
-
-;; Nix object types visible in the XML output of `nix-instantiate' and
-;; mapping to S-expressions (we map to sexps, not records, so that we
-;; can do pattern matching):
-;;
-;;   at               (at varpat attrspat)
-;;   attr             (attribute loc name value)
-;;   attrs            (attribute-set attributes)
-;;   attrspat         (attribute-set-pattern patterns)
-;;   bool             #f|#t
-;;   derivation       (derivation drv-path out-path attributes)
-;;   ellipsis         '...
-;;   expr             (snix loc body ...)
-;;   function         (function loc at|attrspat|varpat)
-;;   int              int
-;;   list             list
-;;   null             'null
-;;   path             string
-;;   string           string
-;;   unevaluated      'unevaluated
-;;   varpat           (varpat name)
-;;
-;; Initially ATTRIBUTES in `derivation' and `attribute-set' was a promise;
-;; however, handling `repeated' nodes makes it impossible to do anything
-;; lazily because the whole SXML tree has to be traversed to maintain the
-;; list of known derivations.
-
-(define (xml-element->snix elem attributes body derivations)
-  "Return an SNix element corresponding to XML element ELEM."
-
-  (define (loc)
-    (location (assq-ref attributes 'path)
-              (assq-ref attributes 'line)
-              (assq-ref attributes 'column)))
-
-  (case elem
-    ((at)
-     (values `(at ,(car body) ,(cadr body)) derivations))
-    ((attr)
-     (let ((name (assq-ref attributes 'name)))
-       (cond ((null? body)
-              (values `(attribute-pattern ,name) derivations))
-             ((and (pair? body) (null? (cdr body)))
-              (values `(attribute ,(loc) ,name ,(car body))
-                      derivations))
-             (else
-              (error "invalid attribute body" name (loc) body)))))
-    ((attrs)
-     (values `(attribute-set ,(reverse body)) derivations))
-    ((attrspat)
-     (values `(attribute-set-pattern ,body) derivations))
-    ((bool)
-     (values (string-ci=? "true" (assq-ref attributes 'value))
-             derivations))
-    ((derivation)
-     (let ((drv-path (assq-ref attributes 'drvPath))
-           (out-path (assq-ref attributes 'outPath)))
-       (if (equal? body '(repeated))
-           (let ((body (vhash-assoc drv-path derivations)))
-             (if (pair? body)
-                 (values `(derivation ,drv-path ,out-path ,(cdr body))
-                         derivations)
-
-                 ;; DRV-PATH hasn't been encountered yet but may be later
-                 ;; (see <http://article.gmane.org/gmane.linux.distributions.nixos/5946>.)
-                 ;; Return an `unresolved' node.
-                 (values `(unresolved
-                           ,(lambda (derivations)
-                              (let ((body (vhash-assoc drv-path derivations)))
-                                (if (pair? body)
-                                    `(derivation ,drv-path ,out-path
-                                                 ,(cdr body))
-                                    (error "no previous occurrence of derivation"
-                                           drv-path)))))
-                         derivations)))
-           (values `(derivation ,drv-path ,out-path ,body)
-                   (vhash-cons drv-path body derivations)))))
-    ((ellipsis)
-     (values '... derivations))
-    ((expr)
-     (values `(snix ,(loc) ,@body) derivations))
-    ((function)
-     (values `(function ,(loc) ,body) derivations))
-    ((int)
-     (values (string->number (assq-ref attributes 'value))
-             derivations))
-    ((list)
-     (values body derivations))
-    ((null)
-     (values 'null derivations))
-    ((path)
-     (values (assq-ref attributes 'value) derivations))
-    ((repeated)
-     (values 'repeated derivations))
-    ((string)
-     (values (assq-ref attributes 'value) derivations))
-    ((unevaluated)
-     (values 'unevaluated derivations))
-    ((varpat)
-     (values `(varpat ,(assq-ref attributes 'name)) derivations))
-    (else (error "unhandled Nix XML element" elem))))
-
-(define (resolve snix derivations)
-  "Return a new SNix tree where `unresolved' nodes from SNIX have been
-replaced by the result of their application to DERIVATIONS, a vhash."
-  (let loop ((node snix)
-             (seen vlist-null))
-    (if (vhash-assq node seen)
-        (values node seen)
-        (match node
-          (('unresolved proc)
-           (let ((n (proc derivations)))
-             (values n seen)))
-          ((tag body ...)
-           (let ((body+seen (fold (lambda (n body+seen)
-                                    (call-with-values
-                                        (lambda ()
-                                          (loop n (cdr body+seen)))
-                                      (lambda (n* seen)
-                                        (cons (cons n* (car body+seen))
-                                              (vhash-consq n #t seen)))))
-                                  (cons '() (vhash-consq node #t seen))
-                                  body)))
-             (values (cons tag (reverse (car body+seen)))
-                     (vhash-consq node #t (cdr body+seen)))))
-          (anything
-           (values anything seen))))))
-
-(define xml->snix
-  (let ((parse
-         (ssax:make-parser NEW-LEVEL-SEED
-                           (lambda (elem-gi attributes namespaces expected-content
-                                    seed)
-                             (cons '() (cdr seed)))
-
-                           FINISH-ELEMENT
-                           (lambda (elem-gi attributes namespaces parent-seed
-                                            seed)
-                             (let ((snix        (car seed))
-                                   (derivations (cdr seed)))
-                               (let-values (((snix derivations)
-                                             (xml-element->snix elem-gi
-                                                                attributes
-                                                                snix
-                                                                derivations)))
-                                 (cons (cons snix (car parent-seed))
-                                       derivations))))
-
-                           CHAR-DATA-HANDLER
-                           (lambda (string1 string2 seed)
-                             ;; Discard inter-node strings, which are blanks.
-                             seed))))
-    (lambda (port)
-      "Return the SNix represention of TREE, an SXML tree as returned by
-parsing the XML output of `nix-instantiate' on Nixpkgs."
-      (match (parse port (cons '() vlist-null))
-        (((snix) . derivations)
-         (resolve snix derivations))))))
-
-(define (attribute-value attribute)
-  "Return the value of ATTRIBUTE."
-  (match attribute
-    (('attribute _ _ value) value)))
-
-(define (derivation-source derivation)
-  "Return the \"src\" attribute of DERIVATION or #f if not found."
-  (match derivation
-    (('derivation _ _ (attributes ...))
-     (find-attribute-by-name "src" attributes))))
-
-(define (derivation-output-path derivation)
-  "Return the output path of DERIVATION."
-  (match derivation
-    (('derivation _ out-path _)
-     out-path)
-    (_ #f)))
-
-(define (source-output-path src)
-  "Return the output path of SRC, the \"src\" attribute of a derivation."
-  (derivation-output-path (attribute-value src)))
-
-(define (source-urls src)
-  "Return the URLs of SRC, the \"src\" attribute of a derivation."
-  (match src
-    (('attribute _ _ ('derivation _ _ (attributes ...)))
-     (match (find-attribute-by-name "urls" attributes)
-       (('attribute _ _ value)
-        value)))
-    (_ #f)))
-
-(define (source-sha256 src)
-  "Return the sha256 of SRC, the \"src\" attribute of a derivation, as a
-bytevector."
-  (match src
-    (('attribute _ _ ('derivation _ _ (attributes ...)))
-     (match (find-attribute-by-name "outputHash" attributes)
-       (('attribute _ _ value)
-        (match value
-          ((= string-length 52)
-           (nix-base32-string->bytevector value))
-          ((= string-length 64)
-           (base16-string->bytevector value))
-          (_
-           (error "unsupported hash format" value))))))
-    (_ #f)))
-
-(define (derivation-source-output-path derivation)
-  "Return the output path of the \"src\" attribute of DERIVATION or #f
-if DERIVATION lacks an \"src\" attribute."
-  (and=> (derivation-source derivation) source-output-path))
-
-(define* (open-nixpkgs nixpkgs #:optional attribute)
-  "Return an input pipe to the XML representation of Nixpkgs.  When
-ATTRIBUTE is true, only that attribute is considered."
-  (with-fluids ((%default-port-encoding "UTF-8"))
-    (let ((cross-system (format #f "{
-  config = \"i686-guix-linux-gnu\";
-  libc = \"glibc\";
-  arch = \"guix\";
-  withTLS = true;
-  float = \"hard\";
-  openssl.system = \"linux-generic32\";
-  platform = (import ~a/pkgs/top-level/platforms.nix).sheevaplug;
-}" nixpkgs)))
-      (apply open-pipe* OPEN_READ
-             "nix-instantiate" "--strict" "--eval-only" "--xml"
-
-             ;; Pass a dummy `crossSystem' argument so that `buildInputs' and
-             ;; `nativeBuildInputs' are not coalesced.
-             ;; XXX: This is hacky and has other problems.
-             ;"--arg" "crossSystem" cross-system
-
-             `(,@(if attribute
-                     `("-A" ,attribute)
-                     '())
-               ,nixpkgs)))))
-
-(define (pipe-failed? pipe)
-  "Close pipe and return its status if it failed."
-  (let ((status (close-pipe pipe)))
-    (if (or (status:term-sig status)
-            (not (= (status:exit-val status) 0)))
-        status
-        #f)))
-
-(define (find-attribute-by-name name attributes)
-  "Return attribute NAME in ATTRIBUTES, an attribute set or list of SNix
-attributes, or #f if NAME cannot be found."
-  (find (lambda (a)
-          (match a
-            (('attribute _ (? (cut string=? <> name)) _)
-             a)
-            (_ #f)))
-        (match attributes
-          (('attribute-set (attributes ...))
-           attributes)
-          (_
-           attributes))))
-
-(define (license-variable license)
-  "Return the name of the (guix licenses) variable for LICENSE."
-  (match license
-    ("GPLv2+"    'gpl2+)
-    ("GPLv3+"    'gpl3+)
-    ("LGPLv2+"   'lgpl2.1+)
-    ("LGPLv2.1+" 'lgpl2.1+)
-    ("LGPLv3+"   'lgpl3+)
-    (('attribute-set _ ...)
-     ;; At some point in 2013, Nixpkgs switched to attribute sets to represent
-     ;; licenses.  These are listed in lib/licenses.nix.
-     (match (and=> (find-attribute-by-name "shortName" license)
-                   attribute-value)
-       ("agpl3Plus"  'agpl3+)
-       ("gpl2Plus"   'gpl2+)
-       ("gpl3Plus"   'gpl3+)
-       ("lgpl2Plus"  'lgpl2.0+)
-       ("lgpl21Plus" 'lgpl2.1+)
-       ("lgpl3Plus"  'lgpl3+)
-       ((? string? x) x)
-       (_             license)))
-    (_           license)))
-
-(define (package-source-output-path package)
-  "Return the output path of the \"src\" derivation of PACKAGE."
-  (derivation-source-output-path (attribute-value package)))
-
-
-;;;
-;;; Conversion of "Nix expressions" to "Guix expressions".
-;;;
-
-(define (snix-derivation->guix-package derivation)
-  "Return the `package' s-expression corresponding to SNix DERIVATION, a
-Nixpkgs `stdenv.mkDerivation'-style derivation, and the original source
-location of DERIVATION."
-  (match derivation
-    (('derivation _ _ (attributes ...))
-     (let*-values (((full-name loc)
-                    (match (find-attribute-by-name "name" attributes)
-                      (('attribute loc _ value)
-                       (values value loc))
-                      (_
-                       (values #f #f))))
-                   ((name version)
-                    (package-name->name+version full-name)))
-       (define (convert-inputs type)
-         ;; Convert the derivation's input from a list of SNix derivations to
-         ;; a list of name/variable pairs.
-         (match (and=> (find-attribute-by-name type attributes)
-                       attribute-value)
-           (#f
-            '())
-           ((inputs ...)
-            ;; Inputs can be either derivations or the null value.
-            (filter-map (match-lambda
-                         (('derivation _ _ (attributes ...))
-                          (let* ((full-name
-                                  (attribute-value
-                                   (find-attribute-by-name "name" attributes)))
-                                 (name (package-name->name+version full-name)))
-                            (list name
-                                  (list 'unquote (string->symbol name)))))
-                         ('null #f))
-                        inputs))))
-
-       (define (maybe-inputs guix-name inputs)
-         (match inputs
-           (()
-            '())
-           ((inputs ...)
-            (list (list guix-name
-                        (list 'quasiquote inputs))))))
-
-       (define (pretty-uri uri version)
-         (if version
-             (match (factorize-uri uri version)
-               ((items ...)
-                `(string-append ,@items))
-               (x x))
-             uri))
-
-       (let* ((source  (find-attribute-by-name "src" attributes))
-              (urls    (source-urls source))
-              (sha256  (source-sha256 source))
-              (meta    (and=> (find-attribute-by-name "meta" attributes)
-                              attribute-value)))
-         (values
-          `(package
-             (name ,name)
-             (version ,version)
-             (source (origin
-                      (method url-fetch)
-                      (uri ,(pretty-uri (car urls) version))
-                      (sha256
-                       (base32
-                        ,(bytevector->nix-base32-string sha256)))))
-             (build-system gnu-build-system)
-
-             ;; When doing a native Nixpkgs build, `buildInputs' is empty and
-             ;; everything is in `nativeBuildInputs'.  So we can't distinguish
-             ;; between both, here.
-             ;;
-             ;; Note that `nativeBuildInputs' was renamed from
-             ;; `buildNativeInputs' in Nixpkgs sometime around March 2013.
-             ,@(maybe-inputs 'inputs
-                             (convert-inputs "nativeBuildInputs"))
-             ,@(maybe-inputs 'propagated-inputs
-                             (convert-inputs "propagatedNativeBuildInputs"))
-
-             (home-page ,(and=> (find-attribute-by-name "homepage" meta)
-                                attribute-value))
-             (synopsis
-              ;; For GNU packages, prefer the official synopsis.
-              ,(or (false-if-exception
-                    (and=> (find (lambda (gnu-package)
-                                   (equal? (gnu-package-name gnu-package)
-                                           name))
-                                 (official-gnu-packages))
-                           gnu-package-doc-summary))
-                   (and=> (find-attribute-by-name "description" meta)
-                          attribute-value)))
-             (description
-              ;; Likewise, prefer the official description of GNU packages.
-              ,(or (false-if-exception
-                    (and=> (find (lambda (gnu-package)
-                                   (equal? (gnu-package-name gnu-package)
-                                           name))
-                                 (official-gnu-packages))
-                           gnu-package-doc-description))
-                   (and=> (find-attribute-by-name "longDescription" meta)
-                          attribute-value)))
-             (license ,(and=> (find-attribute-by-name "license" meta)
-                              (compose license-variable attribute-value))))
-          loc))))))
-
-(define (nixpkgs->guix-package nixpkgs attribute)
-  "Evaluate ATTRIBUTE in NIXPKGS, the file name of a Nixpkgs checkout,
-and return the `package' s-expression corresponding to that package."
-  (let ((port (open-nixpkgs nixpkgs attribute)))
-    (match (xml->snix port)
-      (('snix loc (and drv ('derivation _ ...)))
-       (and (not (pipe-failed? port))
-            (snix-derivation->guix-package drv)))
-      (_
-       (not (pipe-failed? port))))))
-
-;;; snix.scm ends here
diff --git a/guix/scripts/import.scm b/guix/scripts/import.scm
index 98554ef79b..bbd9a3b190 100644
--- a/guix/scripts/import.scm
+++ b/guix/scripts/import.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2014, 2020 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2014, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 David Thompson <davet@gnu.org>
 ;;; Copyright © 2018 Kyle Meyer <kyle@kyleam.com>
 ;;; Copyright © 2019 Ricardo Wurmus <rekado@elephly.net>
@@ -76,7 +76,7 @@ rather than \\n."
 ;;; Entry point.
 ;;;
 
-(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "stackage" "elpa" "gem"
+(define importers '("gnu" "pypi" "cpan" "hackage" "stackage" "elpa" "gem"
                     "go" "cran" "crate" "texlive" "json" "opam"))
 
 (define (resolve-importer name)
diff --git a/guix/scripts/import/nix.scm b/guix/scripts/import/nix.scm
deleted file mode 100644
index 45ca7e3fcf..0000000000
--- a/guix/scripts/import/nix.scm
+++ /dev/null
@@ -1,90 +0,0 @@
-;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2016 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © 2014 David Thompson <davet@gnu.org>
-;;;
-;;; 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 scripts import nix)
-  #:use-module (guix ui)
-  #:use-module (guix utils)
-  #:use-module (guix scripts)
-  #:use-module (guix import snix)
-  #:use-module (guix scripts import)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-11)
-  #:use-module (srfi srfi-37)
-  #:use-module (ice-9 match)
-  #:export (guix-import-nix))
-
-
-;;;
-;;; Command-line options.
-;;;
-
-(define %default-options
-  '())
-
-(define (show-help)
-  (display (G_ "Usage: guix import nix NIXPKGS ATTRIBUTE
-Import and convert the Nix expression ATTRIBUTE of NIXPKGS.\n"))
-  (display (G_ "
-  -h, --help             display this help and exit"))
-  (display (G_ "
-  -V, --version          display version information and exit"))
-  (newline)
-  (show-bug-report-information))
-
-(define %options
-  ;; Specification of the command-line options.
-  (cons* (option '(#\h "help") #f #f
-                 (lambda args
-                   (show-help)
-                   (exit 0)))
-         (option '(#\V "version") #f #f
-                 (lambda args
-                   (show-version-and-exit "guix import nix")))
-         %standard-import-options))
-
-
-;;;
-;;; Entry point.
-;;;
-
-(define (guix-import-nix . args)
-  (define (parse-options)
-    ;; Return the alist of option values.
-    (args-fold* args %options
-                (lambda (opt name arg result)
-                  (leave (G_ "~A: unrecognized option~%") name))
-                (lambda (arg result)
-                  (alist-cons 'argument arg result))
-                %default-options))
-
-  (let* ((opts (parse-options))
-         (args (filter-map (match-lambda
-                            (('argument . value)
-                             value)
-                            (_ #f))
-                           (reverse opts))))
-    (match args
-      ((nixpkgs attribute)
-       (let-values (((expr loc)
-                     (nixpkgs->guix-package nixpkgs attribute)))
-         (format #t ";; converted from ~a:~a~%~%"
-                 (location-file loc) (location-line loc))
-         expr))
-      (x
-       (leave (G_ "wrong number of arguments~%"))))))