From 15d85a5c74d1261dba1148a9483d313de0d2f35b Mon Sep 17 00:00:00 2001
From: Henrik Lissner <henrik@lissner.net>
Date: Tue, 2 Feb 2021 04:48:03 -0500
Subject: [PATCH] Fix nix-mode for nix-shell shell scripts

Wasn't correctly detecting the interpreter argument for nix-shell
shebangs. It must be done in two parts in case cached-nix-shell is
used (which means the shebang will span 2+ lines).
---
 modules/lang/nix/autoload.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/modules/lang/nix/autoload.el b/modules/lang/nix/autoload.el
index cf345407e..d28319f12 100644
--- a/modules/lang/nix/autoload.el
+++ b/modules/lang/nix/autoload.el
@@ -53,7 +53,8 @@
   (save-excursion
     (goto-char (point-min))
     (save-match-data
-      (if (not (re-search-forward "#! *\\(?:cached-\\)?nix-shell +-i +\\([^ \n]+\\)" 256 t))
+      (if (not (and (re-search-forward "\\_<nix-shell " (line-end-position 2) t)
+                    (re-search-forward "-i +\"?\\([^ \"\n]+\\)" (line-end-position) t)))
           (message "Couldn't determine mode for this script")
         (let* ((interp (match-string 1))
                (mode