Vim clears tags after failed omnicompletion

Question

I am using Vim 7.3 with a great deal of plugins, mainly for PHP development. The omnicompletion works well, apart from a small glitch I've come across. I'm trying to work out whether this is a bug in Vim or a problem with my set up, so here's the situation:

I use set tags=<files> to specify the ctags files that I'm using.

:set tags=/home/jon/.vimtags.php,/home/jon/project/.vimtags.php

If I then print the contents of tags, I get what I expect to:

:set tags?
 tags=/home/jon/.vimtags.php,/home/jon/project/.vimtags.php 

I can also use omnicomplete as usual, with <C-x> <C-o>. This is, until I try and complete with something that doesn't exist (i.e. an unknown tag that returns no results). I get the "Pattern not found" error message and then, bizarrely, my tags file list is cleared. If I print the contents of tags straight after, I get:

:set tags?
 tags=

I've done a great deal of grepping on the Vim plugins that I'm using but, as far as I can see, none of them are setting the tags files anywhere.

Can anyone tell me whether this is due to something in my set-up or a bug in Vim itself? Or even whether anyone else finds the same issue?

Answer 1

I can confirm that this isn't default Vim behaviour - it was being caused by the indexer plugin. For some reason, there was a function that reset tags when the omnicomplete failed. I'm going to contact the developer about this, and see if he can come up with a solution.