Raised as https://support.atlassian.com/browse/STSP-24
My core.excludesfile is set to ~/.gitignore, and when I try and use SourceTree's "Edit File" button it just logs this to the console:
10/28/11 1:54:53.547 PM SourceTree: LSOpenFromURLSpec() returned -43 for application TextEdit path ~/.gitignore.
It really needs to expand tildes in the path before trying to open it.