Bad searches should not be stored in the user's session.

1. Enter something in QuickSearch that Lucene doesn't like, for example "989]", and then press Enter
2. Don't do anything else except go straight to an issue (like via History or via a portlet or a bookmarked link or an issue open in another window)
3. Click "Link this issue to an existing issue"
4. Start typing in the issue key input box

The logs get a stack trace that starts with this

2010-02-05 09:53:05,801 http-80-Processor23 ERROR [jira.plugin.issuepick.ConstScoreLuceneCurrentSearchIssuePickerSearchProvider] Error while executing search request
com.atlassian.jira.issue.search.SearchException: org.apache.lucene.queryParser.ParseException: Cannot parse '989]': Lexical error at line 1, column 5.  Encountered: <EOF> after : ""
...
	at com.atlassian.jira.web.dwr.AjaxIssuePicker.getIssues(AjaxIssuePicker
...

The user doesn't see any difference, but I have wasted several cups of coffee repeatedly tracking down this error message every few months (I know, partly my fault for being so dense to not recognize it every time, but, hey, there are a lot of error messages in those logs and some of them really are bad because we have so many plugins)