reproduce issue with 'too many packs' for slotmap

Author: Byron

Cargo.lock

@@ -194,6 +194,10 @@ serde_derive = ">=1.0.185"
 
 once_cell = "1.18.0"
 document-features = { version = "0.2.0", optional = true }
+
+[dev-dependencies]
+tempfile = "3.15.0"
+
 [profile.dev.package]
 insta.opt-level = 3
 similar.opt-level = 3

Cargo.toml

@@ -0,0 +1,52 @@
+use gix::interrupt::IS_INTERRUPTED;
+use gix::remote::Direction;
+
+fn main() -> anyhow::Result<()> {
+    let remote_dir = tempfile::tempdir()?;
+    let remote_repo = gix::init_bare(remote_dir.path())?;
+    create_empty_commit(&remote_repo)?;
+
+    let local_dir = tempfile::tempdir()?;
+    let (local_repo, _) = gix::prepare_clone_bare(remote_repo.path(), local_dir.path())?
+        .fetch_only(gix::progress::Discard, &gix::interrupt::IS_INTERRUPTED)?;
+
+    unsafe { gix::interrupt::init_handler(0, || gix::interrupt::trigger())? };
+
+    let remote = local_repo
+        .branch_remote(
+            local_repo.head_ref()?.expect("branch available").name().shorten(),
+            Direction::Fetch,
+        )
+        .expect("remote is configured after clone")?;
+    for round in 1.. {
+        if gix::interrupt::is_triggered() {
+            eprintln!("Round {round} aborted by user - cleaning up");
+            break;
+        }
+
+        eprintln!("Fetch number {round}…");
+        create_empty_commit(&remote_repo)?;
+        let out = remote
+            .connect(Direction::Fetch)?
+            .prepare_fetch(gix::progress::Discard, Default::default())?
+            .receive(gix::progress::Discard, &IS_INTERRUPTED)?;
+        for local_tracking_branch_name in out.ref_map.mappings.into_iter().filter_map(|m| m.local) {
+            let r = local_repo.find_reference(&local_tracking_branch_name)?;
+            r.id()
+                .object()
+                .expect("object should be present after fetching, triggering pack refreshes works");
+        }
+    }
+    Ok(())
+}
+
+fn create_empty_commit(repo: &gix::Repository) -> anyhow::Result<()> {
+    let name = repo.head_name()?.expect("no detached head");
+    repo.commit(
+        name.as_bstr(),
+        "empty",
+        gix::hash::ObjectId::empty_tree(repo.object_hash()),
+        repo.try_find_reference(name.as_ref())?.map(|r| r.id()),
+    )?;
+    Ok(())
+}

examples/fetch-stress.rs

@@ -1,6 +1,8 @@
 //!
 #![allow(clippy::empty_docs)]
 
+use std::convert::Infallible;
+
 /// An empty array of a type usable with the `gix::easy` API to help declaring no parents should be used
 pub const NO_PARENT_IDS: [gix_hash::ObjectId; 0] = [];
 
@@ -22,6 +24,12 @@ pub enum Error {
     ReferenceEdit(#[from] crate::reference::edit::Error),
 }
 
+impl From<std::convert::Infallible> for Error {
+    fn from(_value: Infallible) -> Self {
+        unreachable!("cannot be invoked")
+    }
+}
+
 ///
 #[cfg(feature = "revision")]
 pub mod describe {