patch 7.4.786
Problem: It is not possible for a plugin to adjust to a changed setting.
Solution: Add the OptionSet autocommand event. (Christian Brabandt)
diff --git a/runtime/doc/autocmd.txt b/runtime/doc/autocmd.txt
index 8a968b9..20523ea 100644
--- a/runtime/doc/autocmd.txt
+++ b/runtime/doc/autocmd.txt
@@ -259,6 +259,7 @@
|Syntax| when the 'syntax' option has been set
|EncodingChanged| after the 'encoding' option has been changed
|TermChanged| after the value of 'term' has changed
+|OptionSet| after setting any option
Startup and exit
|VimEnter| after doing all the startup stuff
@@ -744,6 +745,27 @@
o Operator-pending
i Insert
c Command line
+ *OptionSet*
+OptionSet After setting an option. The pattern is
+ matched against the long option name.
+ The |v:option_old| variable indicates the
+ old option value, |v:option_new| variable
+ indicates the newly set value, the
+ |v:option_type| variable indicates whether
+ it's global or local scoped and |<amatch>|
+ indicates what option has been set.
+
+ Is not triggered on startup and for the 'key'
+ option for obvious reasons.
+
+ Note: It's a bad idea, to reset an option
+ during this autocommand, since this will
+ probably break plugins. You can always use
+ |noa| to prevent triggering this autocommand.
+ Could be used, to check for existence of the
+ 'backupdir' and 'undodir' options and create
+ directories, if they don't exist yet.
+
*QuickFixCmdPre*
QuickFixCmdPre Before a quickfix command is run (|:make|,
|:lmake|, |:grep|, |:lgrep|, |:grepadd|,