Since switching from IDEA 14 to 16.2, I'm seeing that the temporary files created for using an external diff tool have part of the original filename (including the extension) truncated. I use Araxis Merge for diff'ing Excel files (which IntelliJ doesn't support) which are part of one of the projects I work on. The ".xls" file extension is being removed from the temporary file, which causes Araxis to treat the file as text, instead of doing the smarter Sheet/Row level diff that it normally does for recognized Excel files.
For example, when trying to diff "FileFromVcs.xls" from the Version Control log UI, IntelliJ says "Can't show diff" (expected), and I click the "Show Diff in External Tool" link. Araxis is then called with these two files:
Both files exist with those exact names (including the period at the end) and Araxis then shows a binary diff, which is useless.
This worked fine in 14, so I'm assuming it's just a bug. Any ideas?