From c32d8b7a599c0ee0d8936a0c5aee658b5d986453 Mon Sep 17 00:00:00 2001
From: Sebastian Thiel <sebastian.thiel@icloud.com>
Date: Wed, 28 Jul 2021 20:00:28 +0800
Subject: [PATCH] [ref #139] Allow 'git pack-ref --no-purge' essentially

It's surprisingly easy to implement as well, neat.
---
 git-ref/src/store/file/mod.rs                 |  1 +
 git-ref/src/store/file/transaction/mod.rs     | 27 +++++++++++++++++++
 git-ref/src/store/file/transaction/prepare.rs | 18 ++++++++++++-
 .../prepare_and_commit/create_or_update.rs    | 13 +++++----
 4 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/git-ref/src/store/file/mod.rs b/git-ref/src/store/file/mod.rs
index e1ee02e377..f126b82afb 100644
--- a/git-ref/src/store/file/mod.rs
+++ b/git-ref/src/store/file/mod.rs
@@ -34,6 +34,7 @@ pub struct Transaction<'s> {
     store: &'s Store,
     packed_transaction: Option<crate::store::packed::Transaction>,
     updates: Option<Vec<transaction::Edit>>,
+    packed_refs: transaction::PackedRefs,
 }
 
 pub(in crate::store::file) fn path_to_name(path: impl Into<PathBuf>) -> bstr::BString {
diff --git a/git-ref/src/store/file/transaction/mod.rs b/git-ref/src/store/file/transaction/mod.rs
index fca992497f..9a345ef4b3 100644
--- a/git-ref/src/store/file/transaction/mod.rs
+++ b/git-ref/src/store/file/transaction/mod.rs
@@ -5,6 +5,24 @@ use crate::{
 use bstr::BString;
 use git_hash::ObjectId;
 
+/// How to handle packed refs during a transaction
+#[derive(Debug, Clone, Copy)]
+pub enum PackedRefs {
+    /// Only propagate deletions of references. This is the default
+    DeletionsOnly,
+    /// Propagate deletions as well as updates to references which are peeled, that is contain an object id
+    DeletionsAndNonSymbolicUpdates,
+    /// Propagate deletions as well as updates to references which are peeled, that is contain an object id. Furthermore delete the
+    /// reference which is originally updated if it exists. If it doesn't, the new value will be written into the packed ref right away.
+    DeletionsAndNonSymbolicUpdatesRemoveLooseSourceReference,
+}
+
+impl Default for PackedRefs {
+    fn default() -> Self {
+        PackedRefs::DeletionsOnly
+    }
+}
+
 #[derive(Debug)]
 pub(in crate::store::file) struct Edit {
     update: RefEdit,
@@ -46,10 +64,19 @@ impl file::Store {
             store: self,
             packed_transaction: None,
             updates: None,
+            packed_refs: PackedRefs::default(),
         }
     }
 }
 
+impl<'s> Transaction<'s> {
+    /// Configure the way packed refs are handled during the transaction
+    pub fn packed_refs(mut self, packed_refs: PackedRefs) -> Self {
+        self.packed_refs = packed_refs;
+        self
+    }
+}
+
 ///
 pub mod prepare;
 
diff --git a/git-ref/src/store/file/transaction/prepare.rs b/git-ref/src/store/file/transaction/prepare.rs
index 04c04c3dea..4fa8634b02 100644
--- a/git-ref/src/store/file/transaction/prepare.rs
+++ b/git-ref/src/store/file/transaction/prepare.rs
@@ -4,7 +4,10 @@ use crate::{
     store::{
         file,
         file::loose,
-        file::{transaction::Edit, Transaction},
+        file::{
+            transaction::{Edit, PackedRefs},
+            Transaction,
+        },
     },
     transaction::{Change, Create, LogChange, RefEdit, RefEditsExt, RefLog},
 };
@@ -215,6 +218,19 @@ impl<'s> Transaction<'s> {
                 if log_mode == RefLog::Only {
                     continue;
                 }
+                if matches!(
+                    self.packed_refs,
+                    PackedRefs::DeletionsAndNonSymbolicUpdates
+                        | PackedRefs::DeletionsAndNonSymbolicUpdatesRemoveLooseSourceReference
+                ) {
+                    if let Change::Update {
+                        new: Target::Peeled(_), ..
+                    } = edit.update.change
+                    {
+                        edits_for_packed_transaction.push(edit.update.clone());
+                    }
+                    continue;
+                }
                 match edit.update.change {
                     Change::Update {
                         mode: Create::OrUpdate { previous: None },
diff --git a/git-ref/tests/file/transaction/prepare_and_commit/create_or_update.rs b/git-ref/tests/file/transaction/prepare_and_commit/create_or_update.rs
index 958d1287d5..f797751704 100644
--- a/git-ref/tests/file/transaction/prepare_and_commit/create_or_update.rs
+++ b/git-ref/tests/file/transaction/prepare_and_commit/create_or_update.rs
@@ -6,7 +6,10 @@ use bstr::ByteSlice;
 use git_hash::ObjectId;
 use git_lock::acquire::Fail;
 use git_ref::{
-    file::{transaction, WriteReflog},
+    file::{
+        transaction::{self, PackedRefs},
+        WriteReflog,
+    },
     mutable::Target,
     transaction::{Change, Create, LogChange, RefEdit, RefLog},
 };
@@ -504,7 +507,7 @@ fn packed_refs_are_looked_up_when_checking_existing_values() -> crate::Result {
 #[test]
 #[ignore]
 fn packed_refs_creation_with_packed_refs_mode_prune_removes_original_loose_refs() {
-    // Also: make sure tags are going to be peeled
+    // TODO: Also: make sure tags are going to be peeled
     todo!("use file::Store::packed_transaction(), figure out how to incorporate this into loose transactions to support purge/purge-delete-original")
 }
 
@@ -540,15 +543,15 @@ fn packed_refs_creation_with_packed_refs_mode_leave_keeps_original_loose_refs()
 
     let edits = store
         .transaction()
-        // .packed_refs(PackedRefs::Update)
+        .packed_refs(PackedRefs::DeletionsAndNonSymbolicUpdates)
         .prepare(edits, git_lock::acquire::Fail::Immediately)
         .unwrap()
         .commit(&committer())
         .unwrap();
     assert_eq!(
         edits.len(),
-        1,
-        "there really is just one ref that needs updating, symbolic refs are ignored if they don't change the value"
+        2,
+        "it claims to have performed all desired operations, even though some don't make it into the pack as 'side-car'"
     );
 
     assert_eq!(