remote: Update git_fetch_options to use RemoteUpdateFlags

This includes a hacky solution since the `update_flag` field uses C
bitfields, which are not natively supported in Rust.

Author: bnjmnt4n

libgit2-sys/lib.rs

@@ -398,7 +398,7 @@ pub struct git_fetch_options {
     pub version: c_int,
     pub callbacks: git_remote_callbacks,
     pub prune: git_fetch_prune_t,
-    pub update_fetchhead: c_int,
+    pub update_flags: c_uint,
     pub download_tags: git_remote_autotag_option_t,
     pub proxy_opts: git_proxy_options,
     pub depth: c_int,

src/remote.rs

@@ -44,7 +44,7 @@ pub struct FetchOptions<'cb> {
     depth: i32,
     proxy: Option<ProxyOptions<'cb>>,
     prune: FetchPrune,
-    update_fetchhead: bool,
+    update_flags: RemoteUpdateFlags,
     download_tags: AutotagOption,
     follow_redirects: RemoteRedirect,
     custom_headers: Vec<CString>,
@@ -507,7 +507,7 @@ impl<'cb> FetchOptions<'cb> {
             callbacks: None,
             proxy: None,
             prune: FetchPrune::Unspecified,
-            update_fetchhead: true,
+            update_flags: RemoteUpdateFlags::UPDATE_FETCHHEAD,
             download_tags: AutotagOption::Unspecified,
             follow_redirects: RemoteRedirect::Initial,
             custom_headers: Vec::new(),
@@ -538,7 +538,17 @@ impl<'cb> FetchOptions<'cb> {
     ///
     /// Defaults to `true`.
     pub fn update_fetchhead(&mut self, update: bool) -> &mut Self {
-        self.update_fetchhead = update;
+        self.update_flags
+            .set(RemoteUpdateFlags::UPDATE_FETCHHEAD, update);
+        self
+    }
+
+    /// Set whether to report unchanged tips in the update_tips callback.
+    ///
+    /// Defaults to `false`.
+    pub fn report_unchanged(&mut self, update: bool) -> &mut Self {
+        self.update_flags
+            .set(RemoteUpdateFlags::REPORT_UNCHANGED, update);
         self
     }
 
@@ -603,7 +613,11 @@ impl<'cb> Binding for FetchOptions<'cb> {
                 .map(|m| m.raw())
                 .unwrap_or_else(|| ProxyOptions::new().raw()),
             prune: crate::call::convert(&self.prune),
-            update_fetchhead: crate::call::convert(&self.update_fetchhead),
+            // HACK: `libgit2` uses C bitfields, which do not have a guaranteed memory layout.
+            // Reversing the bits ensures that the bitfields are set whether the bits are laid out
+            // from left to right or right to left, but will not work on other memory layouts.
+            update_flags: (self.update_flags.bits() | self.update_flags.bits().reverse_bits())
+                as c_uint,
             download_tags: crate::call::convert(&self.download_tags),
             depth: self.depth,
             follow_redirects: self.follow_redirects.raw(),

systest/build.rs

@@ -24,7 +24,9 @@ fn main() {
         // this field is marked as const which ctest complains about
         (struct_ == "git_rebase_operation" && f == "id") ||
         // the real name of this field is ref but that is a reserved keyword
-        (struct_ == "git_worktree_add_options" && f == "reference")
+        (struct_ == "git_worktree_add_options" && f == "reference") ||
+        // the `update_flags` field consists of 2 bitfields
+        (struct_ == "git_fetch_options" && f == "update_flags")
     });
     cfg.skip_signededness(|s| match s {
         s if s.ends_with("_cb") => true,