somewhat fix the ODB performance bottleneck with better caching.

crates/gitbutler-branch-actions/src/branch.rs

@@ -5,7 +5,7 @@ use core::fmt;
 use gitbutler_branch::{
     Branch as GitButlerBranch, BranchId, BranchIdentity, ReferenceExtGix, Target,
 };
-use gitbutler_command_context::CommandContext;
+use gitbutler_command_context::{CommandContext, GixRepositoryExt};
 use gitbutler_reference::normalize_branch_name;
 use gitbutler_serde::BStringForFrontend;
 use gix::object::tree::diff::Action;
@@ -427,8 +427,7 @@ pub fn get_branch_listing_details(
         .filter_map(Result::ok)
         .collect();
     let git2_repo = ctx.repository();
-    let mut repo = ctx.gix_repository_minimal()?;
-    repo.object_cache_size_if_unset(4 * 1024);
+    let repo = ctx.gix_repository_minimal()?.for_tree_diffing()?;
     let branches = list_branches(ctx, None, Some(branch_names))?;
 
     let (default_target_current_upstream_commit_id, default_target_seen_at_last_update) = {

crates/gitbutler-cli/src/command/mod.rs

@@ -27,6 +27,6 @@ pub mod snapshot {
 }
 
 fn debug_print(this: impl std::fmt::Debug) -> anyhow::Result<()> {
-    eprintln!("{:#?}", this);
+    println!("{:#?}", this);
     Ok(())
 }

crates/gitbutler-command-context/src/lib.rs

@@ -98,3 +98,19 @@ impl CommandContext {
         )?)
     }
 }
+
+pub trait GixRepositoryExt: Sized {
+    /// Configure the repository for diff operations between trees.
+    /// This means it needs an object cache relative to the amount of files in the repository.
+    fn for_tree_diffing(self) -> Result<Self>;
+}
+
+impl GixRepositoryExt for gix::Repository {
+    fn for_tree_diffing(mut self) -> anyhow::Result<Self> {
+        let num_tracked = self.index_or_empty()?.entries().len();
+        let ten_mb_for_every_10k_files =
+            (num_tracked as f32 / 10_000.0) * (10 * 1024 * 1024) as f32;
+        self.object_cache_size_if_unset((ten_mb_for_every_10k_files as usize).max(4 * 1024));
+        Ok(self)
+    }
+}