windows-bindgen 0.60 generates bindings that depend on windows_sys

[djc]

Summary

In trying to upgrade chrono from -bindgen 0.59 to 0.60, I'm seeing this diff:

diff --git a/src/offset/local/win_bindings.rs b/src/offset/local/win_bindings.rs
index f2def25e..79474490 100644
--- a/src/offset/local/win_bindings.rs
+++ b/src/offset/local/win_bindings.rs
@@ -1,10 +1,9 @@
 #![allow(non_snake_case, non_upper_case_globals, non_camel_case_types, dead_code, clippy::all)]
 
-windows_targets::link!("kernel32.dll" "system" fn GetTimeZoneInformationForYear(wyear : u16, pdtzi : *const DYNAMIC_TIME_ZONE_INFORMATION, ptzi : *mut TIME_ZONE_INFORMATION) -> BOOL);
-windows_targets::link!("kernel32.dll" "system" fn SystemTimeToFileTime(lpsystemtime : *const SYSTEMTIME, lpfiletime : *mut FILETIME) -> BOOL);
-windows_targets::link!("kernel32.dll" "system" fn SystemTimeToTzSpecificLocalTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lpuniversaltime : *const SYSTEMTIME, lplocaltime : *mut SYSTEMTIME) -> BOOL);
-windows_targets::link!("kernel32.dll" "system" fn TzSpecificLocalTimeToSystemTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lplocaltime : *const SYSTEMTIME, lpuniversaltime : *mut SYSTEMTIME) -> BOOL);
-pub type BOOL = i32;
+windows_link::link!("kernel32.dll" "system" fn GetTimeZoneInformationForYear(wyear : u16, pdtzi : *const DYNAMIC_TIME_ZONE_INFORMATION, ptzi : *mut TIME_ZONE_INFORMATION) -> windows_sys::core::BOOL);
+windows_link::link!("kernel32.dll" "system" fn SystemTimeToFileTime(lpsystemtime : *const SYSTEMTIME, lpfiletime : *mut FILETIME) -> windows_sys::core::BOOL);
+windows_link::link!("kernel32.dll" "system" fn SystemTimeToTzSpecificLocalTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lpuniversaltime : *const SYSTEMTIME, lplocaltime : *mut SYSTEMTIME) -> windows_sys::core::BOOL);
+windows_link::link!("kernel32.dll" "system" fn TzSpecificLocalTimeToSystemTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lplocaltime : *const SYSTEMTIME, lpuniversaltime : *mut SYSTEMTIME) -> windows_sys::core::BOOL);
 #[repr(C)]
 #[derive(Clone, Copy)]
 pub struct DYNAMIC_TIME_ZONE_INFORMATION {

Note that the generated code contains the return type of windows_sys::core::BOOL, but part of the goal of using windows-bindgen is that we can avoid the dependency on windows-sys.

Crate manifest

[target.'cfg(windows)'.dependencies]
windows-link = { version = "0.1", optional = true }
[target.'cfg(windows)'.dev-dependencies]
windows-bindgen = { version = "0.60" } # MSRV is 1.74

Crate code

use std::fs;
use windows_bindgen::bindgen;

#[test]
fn gen_bindings() {
    let input = "src/offset/local/win_bindings.txt";
    let output = "src/offset/local/win_bindings.rs";
    let existing = fs::read_to_string(output).unwrap();

    bindgen(["--etc", input]);

    // Check the output is the same as before.
    // Depending on the git configuration the file may have been checked out with `\r\n` newlines or
    // with `\n`. Compare line-by-line to ignore this difference.
    let mut new = fs::read_to_string(output).unwrap();
    if existing.contains("\r\n") && !new.contains("\r\n") {
        new = new.replace("\n", "\r\n");
    } else if !existing.contains("\r\n") && new.contains("\r\n") {
        new = new.replace("\r\n", "\n");
    }

    similar_asserts::assert_eq!(existing, new);
    if !new.lines().eq(existing.lines()) {
        panic!("generated file `{}` is changed.", output);
    }
}

[ChrisDenton]

You can use --no-core to prevent that.

See also #3359

[ChrisDenton]

Oh just a heads up, that flag has been renamed to --no-deps in newer versions as it's goal is to ensure exactly what you want; i.e. the code having no dependencies. #3492

[kennykerr]

I should probably add the most common options to the crate's readme page. 🤔

[djc]

Alright, that fixed it -- thanks for the help!

In terms of the upgrading experience, the Dependabot PRs include a copy of the GitHub release notes, but it's a copy from when the PR was made -- it looks like the release notes were substantially expanded after that. Even now, this particular breaking change is not mentioned in the release notes. It might be nicer for downstreams if there were per-crate release notes instead of a larger write up that includes all the stuff.