files extracted from zips are missing execute permissions

[travisstaloch]

Zig Version

0.14.0-dev.875+ebd0c6ffd

Steps to Reproduce and Observed Behavior

This issue was reported here. That project uses the package manager to download zips from https://github.com/protocolbuffers/protobuf/releases/. When I unzip one of the zip files manually, the permissions look fine.

-r-xr-xr-x 1 17M May 22 11:45 protoc

But with the package manager I guess they turn into the following as reported in the issue above.

-rw-r--r-- protoc

I asked @marler8997 about this and he said

I don't think I implemented the extension for unix file permissions.

So it sounds like this just hasn't been implemented yet. zip support was added in #19729.

Expected Behavior

Execute permissions should be preserved.

[andrewrk]

To be clear, the expected behavior from the package manager is to ignore permissions from the zip file and set the execute bit based on ELF header and shebang line alone (see #17463). I set the milestone to 0.14.0 in case that is not implemented correctly.

As for implementing extensions in the standard library, that's a separate issue.

[owenbrooks]

For MacOS, that zig-protobuf project downloads the protoc binary in Mach-O file format, so it doesn't get set to executable. Is it worth adding Mach-O header detection to the isExecutable check in addition to ELF and shebang?

[fabioarnold]

Is it worth adding Mach-O header detection to the isExecutable check in addition to ELF and shebang?

I opened a PR here: #21555