error: unknown type name 'GIT_BEGIN_DECL'

[kornelski]

The version of libgit2-sys on crates.io has stopped building on my machine (upgrade to macOS 12 beta may have been related) for an odd reason: GIT_BEGIN_DECL is undefined.

The issue is reliably reproducible, with both Apple clang and Homebrew gcc 11.

warning: In file included from libgit2/src/alloc.c:8:
warning: In file included from libgit2/src/alloc.h:11:
warning: /private/tmp/foo/target/debug/build/libgit2-sys-a2d40bc23ad2df82/out/include/git2/sys/alloc.h:13:1: error: unknown type name 'GIT_BEGIN_DECL'
warning: GIT_BEGIN_DECL
warning: ^

The problem appears to be fixed in the latest git of git2-rs (as of 7d12405), i.e:

git2 = "0.13.20"

doesn't build, but:

git2 = { git = "https://github.com/rust-lang/git2-rs" }

builds fine.

Therefore, can you release the latest changes?

[ehuss]

Hm. We can definitely make a new release, but I am a bit surprised that it would make a difference because there haven't been any changes that would necessarily affect the build of libgit2-sys here. (Changes listed here.) The only change that might be relevant is the vendored-openssl change, but that should only affect the linking of openssl, and only if you are using that feature (are you?). I also wouldn't expect the use of openssl to change the parsing of a header.

Looking at the code, I don't see how that can fail. The top of sys/alloc.h imports git2/common.h which defines GIT_BEGIN_DECL. I don't see how it is possible for that to be undefined.

Does using git2 = { git = "https://github.com/rust-lang/git2-rs", tag="0.13.20" } still fail? I'm wondering if there is some difference in how it is built as a "path-style" dependency (there are various subtle differences).

I'm also wondering, do you maybe have libgit2 installed via homebrew (or anywhere else)? I'm just wondering, if maybe similar to #721 there is some interaction with the system-installed copy.

[kornelski]

Yeah, that's weird! The git dependency from the tag works, the crates.io dep doesn't.

[kornelski]

Oh, nevermind. rm -rf ~/.cargo/registry/ fixed it. My registry copy must have gotten corrupted somehow. Sorry for the false alarm.