unzipping a file with with read only permissions on its zipped folders breaks

[trashhalo]

Describe the bug
When you try to unzip a file that has permissions set to be read only on internal directory structure it will blow up bad match eaccess error because it's trying to create files in the folder that's read only.

To Reproduce

1. download zip file file_test.zip
2. mkdir target
3. :zip.unzip(~c"file_test.zip", cwd: ~c"target") (elixir code)

iex(1)> :zip.unzip(~c"file_test.zip", cwd: ~c"target")
{:error,
 {:EXIT,
  {{:badmatch, {:error, :eacces}},
   [
     {:zip, :file_io, 2, [file: ~c"zip.erl", line: 2757]},
     {:zip, :get_z_file, 11, [file: ~c"zip.erl", line: 2286]},
     {:zip, :get_z_files, 5, [file: ~c"zip.erl", line: 2231]},
     {:zip, :do_unzip, 2, [file: ~c"zip.erl", line: 425]},
     {:zip, :unzip, 2, [file: ~c"zip.erl", line: 410]},
     {:elixir, :eval_external_handler, 3, [file: ~c"src/elixir.erl", line: 386]},
     {:erl_eval, :do_apply, 7, [file: ~c"erl_eval.erl", line: 919]},
     {:elixir, :eval_forms, 4, [file: ~c"src/elixir.erl", line: 364]}
   ]}}}
iex(2)> :zip.unzip(~c"file_test.zip")

Expected behavior
It unzips the files into the folder target.

Affected versions
OTP 27.2, but my guess is it was introduced in 27.1

Additional context
Id also settle for a option to not carry forward permissions from the zip file. Suprisingly it works if you dont pass a cwd. 🤔

[trashhalo]

@garazdawi I think you may have introduced this issue here. d6c4e1f

[garazdawi]

Thanks for the report. The right thing to do here is probably to set all directory permissions after we have created all files and directories... and there should probably also be an option added to ignore all permissions in the archive.

[garazdawi]

Fix available in #9335, please test it with your original problem.

[akoutmos]

Just came across this bug as well and it was a doozy to figure out what was going on lol.

One work around for this while we wait for a new release is to do (in Elixir) :zip.extract(zip_path, [:memory]) and then manually go through the contents of the files and write the files out manually. This way you don't need to worry about the file permissions.

[trashhalo]

Just came across this bug as well and it was a doozy to figure out what was going on lol.

One work around for this while we wait for a new release is to do (in Elixir) :zip.extract(zip_path, [:memory]) and then manually go through the contents of the files and write the files out manually. This way you don't need to worry about the file permissions.

I'm so glad it wasn't just me that lost a day to try to figure this out. Was one of the harder bugs I've hit to trace. Huge thanks to @garazdawi for quick fix!