Put all the ls logic into the function

Doing it when sourcing isn't necessary or all that great.

Just make it an actual normal function file.

share/functions/ls.fish

@@ -1,21 +1,25 @@
-#
-# Make ls use colors and show indicators if we are on a system that supports that feature and writing to stdout.
-#
+function ls --description "List contents of directory"
+    # Make ls use colors and show indicators if we are on a system that supports that feature and writing to stdout.
+    #
 
-# BSD, macOS and others support colors with ls -G.
-# GNU ls and FreeBSD ls takes --color=auto. Order of this test is important because ls also takes -G but it has a different meaning.
-# Solaris 11's ls command takes a --color flag.
-# Also test -F because we'll want to define this function even with an ls that can't do colors (like NetBSD).
-
-for opt in --color=auto -G --color -F
-    if command ls $opt / >/dev/null 2>/dev/null
-        function ls --description "List contents of directory" -V opt
-            __fish_set_lscolors
-            isatty stdout
-            and set -a opt -F
-            command ls $opt $argv
+    # BSD, macOS and others support colors with ls -G.
+    # GNU ls and FreeBSD ls takes --color=auto. Order of this test is important because ls also takes -G but it has a different meaning.
+    # Solaris 11's ls command takes a --color flag.
+    # Also test -F because we'll want to define this function even with an ls that can't do colors (like NetBSD).
+    if not set -q __fish_ls_color_opt
+        set -g __fish_ls_color_opt
+        for opt in --color=auto -G --color -F
+            if command ls $opt / >/dev/null 2>/dev/null
+                set -g __fish_ls_color_opt $opt
+                break
+            end
         end
-
-        break
     end
+
+    # Set the colors to the default via `dircolors` if none is given.
+    __fish_set_lscolors
+
+    isatty stdout
+    and set -a opt -F
+    command ls $__fish_ls_color_opt $argv
 end