Subject: emacs: fix odt export

From: [email-masked] (Nicolò Balzarotti)
Date: Sun, 15 Dec 2019 00:45:09 +0100

Hello Guix!

Neither on NixOS or in guix I've ever been able to export an org file to
otd. The error was
'OpenDocument export failed: Buffer is read-only: #<killed buffer>'.

I've seen some report of this error on the web, like:
- https://lists.gnu.org/archive/html/emacs-orgmode/2018-05/msg00545.html
- https://github.com/syl20bnr/spacemacs/issues/1482

but also on our IRC:
- http://logs.guix.gnu.org/guix/2019-05-07.log
- http://logs.guix.gnu.org/guix/2019-07-25.log
but I was not able to find a fix for it.

Today I checked the source and figured it out. The explanation, as
written in the patch, is the following

> Files inside the guix store are read only. "styles.xml" is copied from the
> store (/share/emacs/26.3/etc/org/OrgOdtStyles.xml), so it's read only too.
> ox-odt needs this file, so if it's not writable it will fail. This patch
> adjust the permissions.

So, this patches fixes the permissions on the file.

I've two questions:
1. Is it fine to have a .patch, or should I add a phase where I fix the
   file? this seemed to be easier
2. If the same error happens for other programs, might it make sense to
   "fake" rw permissions in the store (by using a virtual fs or
   something) so that files are copied as rw, but files in the store are
   still ro?

Thanks!

Nicolò

>From c1ad3fff9bda5935651f26e460907a77d1b3d003 Mon Sep 17 00:00:00 2001
From: nixo <[email-masked]>
Date: Sat, 14 Dec 2019 15:17:11 +0100
Subject: [PATCH] * gnu/packages/emascs.scm (emacs)[patches]: Fix odt export.

ox-odt copyes the file /share/emacs/26.3/etc/org/OrgOdtStyles.xml under
/tmp/odt-*/styles.xml and tries to modify it.  Since files in the guix store
are read-only, it will fail.  This patch fixes the export by adjusting
permissions during the export.
---
 gnu/packages/emacs.scm                        |  1 +
 .../patches/emacs-fix-odt-export.patch        | 25 +++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 gnu/packages/patches/emacs-fix-odt-export.patch

diff --git a/gnu/packages/emacs.scm b/gnu/packages/emacs.scm
index eba7f88551..8183b69eb3 100644
--- a/gnu/packages/emacs.scm
+++ b/gnu/packages/emacs.scm
@@ -80,6 +80,7 @@
                "119ldpk7sgn9jlpyngv5y4z3i7bb8q3xp4p0qqi7i5nq39syd42d"))
              (patches (search-patches "emacs-exec-path.patch"
                                       "emacs-fix-scheme-indent-function.patch"
+                                      "emacs-fix-odt-export.patch"
                                       "emacs-source-date-epoch.patch"))
              (modules '((guix build utils)))
              (snippet
diff --git a/gnu/packages/patches/emacs-fix-odt-export.patch b/gnu/packages/patches/emacs-fix-odt-export.patch
new file mode 100644
index 0000000000..0c3c44a2e3
--- /dev/null
+++ b/gnu/packages/patches/emacs-fix-odt-export.patch
@@ -0,0 +1,25 @@
+Files inside the guix store are read only. "styles.xml" is copied from the
+store (/share/emacs/26.3/etc/org/OrgOdtStyles.xml), so it's read only too.
+ox-odt needs this file, so if it's not writable it will fail. This patch
+adjust the permissions.
+
+---
+ lisp/org/ox-odt.el | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/lisp/org/ox-odt.el b/lisp/org/ox-odt.el
+index f9c4a93cc8..61988ffcc4 100644
+--- a/lisp/org/ox-odt.el
++++ b/lisp/org/ox-odt.el
+@@ -1384,6 +1384,8 @@ original parsed data.  INFO is a plist holding export options."
+     ;; create a manifest entry for styles.xml
+     (org-odt-create-manifest-file-entry "text/xml" "styles.xml")
+ 
++    ;; guix store files are ro. This file need to be modified, make it rw
++    (set-file-modes (concat org-odt-zip-dir "styles.xml") #o600)
+     ;; FIXME: Who is opening an empty styles.xml before this point?
+     (with-current-buffer
+ 	(find-file-noselect (concat org-odt-zip-dir "styles.xml") t)
+-- 
+2.24.0
+
-- 
2.24.0