This crash occurs due to a change introduced in D8671 (which isn't yet in upstream, but is still an important fix for Phragment).

Basically the code would attempt to create a directory entry twice, because there were entries like:

• abc/def.txt

in the ZIP file, but it didn't yet have an entry for abc/. This code would add abc/ to the explicit paths to be created, but D8671 introduced a change whereby these preceding paths would automatically be created when abc/def.txt was updated or created. Because the added entry would result in an iteration like:

• abc/def.txt
• abc/

This would crash with a duplicate key exception, because abc/ had already been created in the abc/def.txt update.

This only happens the first time that a directory is missing; obviously the first call to create the directory as part of abc/def.txt in the example above will result in it not being an issue the second time around.

I've tested this change against a normal build (where no new directories were introduced) and nothing broke, so worst case scenario we're in no better position than we started with (but I am fairly confident that this is the correct fix for the issue).