FreeBSD cycle detected when const-evaluating

[ryanavella]

I get the following error both when running cargo install https and git clone ... && cd http && cargo build (i.e. latest commit on master branch)

I'm not exactly sure what your build.rs is doing, but FreeBSD has the function getbsize which might be helpful here?

error[E0391]: cycle detected when const-evaluating + checking `util::os::non_windows_non_macos::BLKGETSIZE`
  --> http/target/debug/build/https-db5e3b91851aac53/out/ioctl-data/ioctl.rs:3:1
   |
3  | static BLKGETSIZE: libc::c_ulong = BLKGETSIZE as libc::c_ulong;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: ...which requires const-evaluating + checking `util::os::non_windows_non_macos::BLKGETSIZE`...
  --> http/target/debug/build/https-db5e3b91851aac53/out/ioctl-data/ioctl.rs:3:36
   |
3  | static BLKGETSIZE: libc::c_ulong = BLKGETSIZE as libc::c_ulong;
   |                                    ^^^^^^^^^^
   = note: ...which again requires const-evaluating + checking `util::os::non_windows_non_macos::BLKGETSIZE`, completing the cycle
note: cycle used when elaborating drops for `util::os::non_windows_non_macos::file_length_impl`
  --> src/util/os/non_windows_non_macos.rs:39:47
   |
39 |             let ok = unsafe { ioctl(dev_file, BLKGETSIZE, &mut block_count as *mut c_ulong) } == 0;
   |                                               ^^^^^^^^^^
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

For more information about this error, try `rustc --explain E0391`.
error: could not compile `https` (bin "http") due to previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `https` (bin "httplz") due to previous error

Meta

rustc --version --verbose:

rustc 1.74.1 (a28077b28 2023-12-04)
binary: rustc
commit-hash: a28077b28a02b92985b3a3faecf92813155f1ea1
commit-date: 2023-12-04
host: x86_64-unknown-freebsd
release: 1.74.1
LLVM version: 17.0.4

cargo --version --verbose

cargo 1.74.1 (ecb9851af 2023-10-18)
release: 1.74.1
commit-hash: ecb9851afd3095e988daaa35a48bc7f3cb748e04
commit-date: 2023-10-18
host: x86_64-unknown-freebsd
libgit2: 1.7.1 (sys:0.18.0 vendored)
libcurl: 8.4.0-DEV (sys:0.4.68+curl-8.4.0 vendored ssl:OpenSSL/1.1.1u)
ssl: OpenSSL 1.1.1u  30 May 2023
os: FreeBSD 14.0-RELEASE-p3 [64-bit]

uname -imrs

FreeBSD 14.0-RELEASE amd64 GENERIC

[ryanavella]

I tried the following quick hack to bypass build.rs:

-#[cfg(any(target_os = "windows", target_os = "macos"))]
+#[cfg(any(target_os = "windows", target_os = "macos", target_os = "freebsd"))]
 fn get_ioctl_data() {}
 
-#[cfg(not(any(target_os = "windows", target_os = "macos")))]
+#[cfg(not(any(target_os = "windows", target_os = "macos", target_os = "freebsd")))]
 fn get_ioctl_data() {
     let ioctl_dir = Path::new(&env::var("OUT_DIR").unwrap()).join("ioctl-data");

Compilation proceeded even further but it still produces an error:

error: couldn't read http/target/debug/build/https-db5e3b91851aac53/out/ioctl-data/ioctl.rs: No such file or directory (os error 2)
 --> src/util/os/non_windows_non_macos.rs:9:1
  |
9 | include!(concat!(env!("OUT_DIR"), "/ioctl-data/ioctl.rs"));
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `include` (in Nightly builds, run with -Z macro-backtrace for more info)

error: could not compile `https` (bin "http") due to previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `https` (bin "httplz") due to previous error

So unfortunately I don't think there is a quick-fix. Currently FreeBSD is compiled as if it were Linux, but FreeBSD doesn't have an ioctl parallel to BLKGETSIZE so I think it may need its own separate cfg.

[ryanavella]

@nabijaczleweli You mentioned over in #158

this should probably use the same methodology as I do in voreutils (https://git.sr.ht/~nabijaczleweli/voreutils/tree/02bcd701febb555147b67e0fa7fdc1504fe3cca2/item/cmd/wc.cpp#L155-177), which includes Linux, {Free,Net}BSD, OpenBSD, and the illumos gate. maybe drop the illumos gate. I'll probably do this in a bit but this is incredibly annoying to do in Rust

Can you clarify which part is "incredibly annoying" about porting this from C++ to Rust? Is it the fact that macro-expanding requires invoking cc in build.rs?

I'm wondering if perhaps we could pre-expand it to a constant and trust that the constant is unlikely to change.

If you take a look at git-blame for FreeBSD's DIOCGMEDIASIZE constant, the most recent commit was 13 years ago, and even that only modified a comment and not the macro itself. So I do think the macro is likely relatively stable.
https://github.com/freebsd/freebsd-src/blob/fb03f7f8e30d21ad74ef7a3ee1b4a7e546fef852/sys/sys/disk.h#L35

[nabijaczleweli]

"Closes:" tag closed the PR but not the issue? Must be a wednesday in githubland. Anyway, try with current develop (at least be7de13)?

[ryanavella]

Excellent, be7de13 works for me, thanks for looking into this!

[nabijaczleweli]

Released in v2.0.0.