From a9d426c492e7834bf658ab598fea3be32608839d Mon Sep 17 00:00:00 2001
From: Thiago Jung Bauermann <bauermann@kolabnow.com>
Date: Fri, 3 Dec 2021 23:16:11 -0300
Subject: [PATCH] gnu: Add texlive-latex-luatex.
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When TeX Live was updated to version 2021 the ‘lualatex’ format started
being generated with the LuaHBTeX engine, but the ‘lualatex’ command still
uses the LuaTeX engine. This causes the command to fail:

  user@popigai:~$ lualatex hello.tex
  This is LuaTeX, Version 1.13.0 (TeX Live 2021/GNU Guix)
  restricted system commands enabled.

  ---! lualatex.fmt was written by luahbtex
  (Fatal format file error; I'm stymied)user@popigai:~$

The correct way to fix this problem would be either to change texlive-bin
to make ‘lualatex’ use the LuaHBTeX engine, or to change texlive-latex-base
to generate ‘lualatex.fmt’ with LuaTeX. Both options would rebuild large
parts of the world.

Ricardo Wurmus suggested creating a new package to provide ‘lualatex.fmt’
for LuaTeX as a workaround. This is what this package does.

Fixes https://issues.guix.gnu.org/51252.

* gnu/packages/tex.scm (texlive-latex-luatex): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
---
 gnu/packages/tex.scm | 65 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/gnu/packages/tex.scm b/gnu/packages/tex.scm
index 910be212ac..256fe7da90 100644
--- a/gnu/packages/tex.scm
+++ b/gnu/packages/tex.scm
@@ -3746,6 +3746,71 @@ (define-public texlive-luaotfload
 
 (define-deprecated-package texlive-luatex-luaotfload texlive-luaotfload)
 
+;; FIXME: This package is a temporary workaround to provide ‘lualatex.fmt’ for
+;; the LuaTeX engine. It is needed because it was discovered too late in the
+;; core-updates-frozen cycle that texlive-latex-base only provides it for
+;; LuaHBTeX. See https://issues.guix.gnu.org/51252.
+(define-public texlive-latex-luatex
+  (package
+    (name "texlive-latex-luatex")
+    (version (number->string %texlive-revision))
+    (source #f)
+    (build-system gnu-build-system)
+    (arguments
+     `(#:modules ((guix build gnu-build-system)
+                  (guix build utils)
+                  (ice-9 rdelim)
+                  (ice-9 string-fun))
+       #:phases
+       (modify-phases %standard-phases
+         (delete 'unpack)
+         (delete 'bootstrap)
+         (delete 'configure)
+         (delete 'check)
+         (replace 'build
+           (lambda* (#:key inputs #:allow-other-keys)
+             (mkdir "web2c")
+             (let ((fmtutil.cnf-in (open-file
+                                    (string-append
+                                     (assoc-ref inputs "texlive-kpathsea")
+                                     "/share/texmf-dist/web2c/fmtutil.cnf")
+                                    "r"))
+                   (fmtutil.cnf-out (open-file "web2c/fmtutil.cnf" "w")))
+
+               ;; Copy ‘lualatex’ format lines to the new fmtutil.cnf, changing
+               ;; the engine from ‘luahbtex’ to ‘luatex’.
+               (do ((line "" (read-line fmtutil.cnf-in 'concat)))
+                   ((eof-object? line))
+                 (when (string-prefix? "lualatex" line)
+                   (display (string-replace-substring line "luahbtex" "luatex")
+                            fmtutil.cnf-out)))
+               (close-port fmtutil.cnf-out)
+               (close-port fmtutil.cnf-in)
+
+               (invoke "fmtutil" "--sys" "--all" "--fmtdir=web2c"
+                       "--cnffile=web2c/fmtutil.cnf")
+
+               ;; Don't risk this file interfering with anything else.
+               (delete-file "web2c/fmtutil.cnf"))))
+         (replace 'install
+           (lambda* (#:key outputs #:allow-other-keys)
+             (let ((web2c (string-append %output "/share/texmf-dist/web2c")))
+               (mkdir-p web2c)
+               (copy-recursively "web2c" web2c)))))))
+    (native-inputs
+     `(("texlive-bin" ,texlive-bin)
+       ("texlive-babel" ,texlive-babel)
+       ("texlive-cm" ,texlive-cm)
+       ("texlive-fonts-latex" ,texlive-fonts-latex)
+       ("texlive-kpathsea" ,texlive-kpathsea)
+       ("texlive-latex-base" ,texlive-latex-base)
+       ("texlive-lm" ,texlive-lm)
+       ("texlive-tex-ini-files" ,texlive-tex-ini-files)))
+    (home-page (package-home-page texlive-latex-base))
+    (synopsis "LuaLaTeX format files for LuaTeX")
+    (description "This package is necessary to use LaTeX with the LuaTeX engine.")
+    (license (package-license texlive-latex-base))))
+
 (define-public texlive-latex-amsmath
   (package
     (name "texlive-latex-amsmath")