RubyZip successfully opens a completely blank "zip file"

[weshatheleopard]

> Zip::File.open_buffer('')
=> #<Zip::File:0x00007f5e6803de50 @entry_set=#<Zip::EntrySet:0x00007f5e6803dcc0 @entry_set={}>, @comment="", @name=#<StringIO:0x00007f5e6803de78>, .......

The expectation would be that such attempt fails with an "invalid ZIP format" error, as the "file" doesn't even have the ZIP signature ('PK') at the start.

[hainesr]

Which version of Rubyzip are you using?

Older versions seem to assume that when a buffer is passed then it is creating a new zip - so this would succeed by default.

[weshatheleopard]

Version 2.3.2

And no, I've been passing a buffer with a downloaded ZIP file to open, for years by now.

It's just that recently the website I was downloading the zip file from, started returning zero-length file. And instead of erring out that there's no archive to read from to begin with, ZIP gem claimed that there is an archive but there are no files in it, which sent me down the wrong path.

[hainesr]

Oh yes, it will still work, but it does set the create flag on buffers, so an empty buffer wouldn't be raised as an error. This is changed in the (as yet unreleased) version.