Merge pull request #78: Make color scheme persistence configurable

Related comments/issues/pull requests:
 - #6 (comment)
 - #78
 - #96

README.md

@@ -161,6 +161,12 @@ The session load/save prompts are quite verbose by default because they explain
 
 By default this option is set to false (0). When you set this option to true (1) and you start Vim, the session plug-in will open your last used session instead of the default session. Note that the session plug-in will still show you the dialog asking whether you want to restore the last used session. To get rid of the dialog you have to set `g:session_autoload` to `'yes'`.
 
+### The `g:session_persist_colors` option
+
+By default the plug-in will save the color scheme and the ['background' option] [bg] with the session to be reused the next time that session is loaded, this can be disabled by adding the following line to your [vimrc script] [vimrc]:
+
+    :let g:session_persist_colors = 0
+
 ### The `g:session_persist_globals` option
 
 The vim-session plug-in uses Vim's [:mksession] [mksession] command but it changes ['sessionoptions'][sessionoptions] so that Vim options and mappings are not persisted. The plug-in does this because persistence of options and mappings can break loading of sessions, in other words it's fragile (in my opinion).
@@ -246,7 +252,7 @@ Recently this plug-in switched from reimplementing [:mksession][mksession] to ac
 <!-- Start of generated documentation -->
 
 The documentation of the 34 functions below was extracted from
-1 Vim scripts on July  6, 2014 at 20:47.
+1 Vim scripts on July  6, 2014 at 21:01.
 
 ### Public API for the vim-session plug-in
 
@@ -554,6 +560,7 @@ Here's an example session script generated by the vim-session plug-in while I wa
     unlet SessionLoad
 
 
+[bg]: http://vimdoc.sourceforge.net/htmldoc/options.html#'background'
 [delcommand]: http://vimdoc.sourceforge.net/htmldoc/map.html#:delcommand
 [download-misc]: http://peterodding.com/code/vim/downloads/misc.zip
 [download-session]: http://peterodding.com/code/vim/downloads/session.zip

autoload/xolox/session.vim

@@ -4,7 +4,7 @@
 " Last Change: July 6, 2014
 " URL: http://peterodding.com/code/vim/session/
 
-let g:xolox#session#version = '2.4.15'
+let g:xolox#session#version = '2.5'
 
 " Public API for session persistence. {{{1
 
@@ -45,14 +45,14 @@ function! xolox#session#save_session(commands, filename) " {{{2
   call xolox#session#save_globals(a:commands)
   if is_all_tabs
     call xolox#session#save_features(a:commands)
-    call xolox#session#save_colors(a:commands)
+    if g:session_persist_colors
+      call xolox#session#save_colors(a:commands)
+    endif
   endif
   call xolox#session#save_qflist(a:commands)
   call xolox#session#save_state(a:commands)
   if is_all_tabs
     call xolox#session#save_fullscreen(a:commands)
-  endif
-  if is_all_tabs
     call add(a:commands, 'doautoall SessionLoadPost')
   else
     call add(a:commands, 'let s:winrestcmd = winrestcmd()')

doc/session.txt

@@ -28,11 +28,12 @@ Contents ~
   8. The |g:session_autosave_periodic| option
   9. The |g:session_verbose_messages| option
   10. The |g:session_default_to_last| option
-  11. The |g:session_persist_globals| option
-  12. The |g:session_restart_environment| option
-  13. The |g:session_command_aliases| option
-  14. The |g:session_menu| option
-  15. The |g:loaded_session| option
+  11. The |g:session_persist_colors| option
+  12. The |g:session_persist_globals| option
+  13. The |g:session_restart_environment| option
+  14. The |g:session_command_aliases| option
+  15. The |g:session_menu| option
+  16. The |g:loaded_session| option
  5. Compatibility with other plug-ins |session-compatibility-with-other-plug-ins|
  6. Known issues                                         |session-known-issues|
  7. Function reference                             |session-function-reference|
@@ -363,6 +364,15 @@ instead of the default session. Note that the session plug-in will still show
 you the dialog asking whether you want to restore the last used session. To get
 rid of the dialog you have to set |g:session_autoload| to "'yes'".
 
+-------------------------------------------------------------------------------
+The *g:session_persist_colors* option
+
+By default the plug-in will save the color scheme and the |'background'| option
+with the session to be reused the next time that session is loaded, this can be
+disabled by adding the following line to your |vimrc| script:
+>
+  :let g:session_persist_colors = 0
+<
 -------------------------------------------------------------------------------
 The *g:session_persist_globals* option
 
@@ -490,7 +500,7 @@ might take a while...)
 Function reference ~
 
 The documentation of the 34 functions below was extracted from 1 Vim scripts on
-July 6, 2014 at 20:47.
+July 6, 2014 at 21:01.
 
 -------------------------------------------------------------------------------
                                            *public-api-for-vim-session-plug-in*

plugin/session.vim

@@ -1,6 +1,6 @@
 " Vim script
 " Author: Peter Odding
-" Last Change: June 22, 2014
+" Last Change: July 6, 2014
 " URL: http://peterodding.com/code/vim/session/
 
 " Support for automatic update using the GLVS plug-in.
@@ -109,6 +109,11 @@ if !exists('g:session_menu')
   let g:session_menu = 1
 endif
 
+" Toggle the persistence of color schemes and the 'background' option.
+if !exists('g:session_persist_colors')
+  let g:session_persist_colors = 1
+endif
+
 " Make sure the sessions directory exists and is writable. {{{1
 
 let s:directory = fnamemodify(g:session_directory, ':p')