From a476f298eaed5cda5b8efc951a6742aac9c519ea Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh@glandium.org>
Date: Thu, 2 Nov 2023 20:05:06 +0900
Subject: [PATCH] Avoid resetting metadata history when recloning with
 cinnabarclone

---
 src/cinnabar-helper.c | 38 +++++++++++++++++++-------------------
 src/cinnabar-helper.h |  2 +-
 src/main.rs           | 17 +++++++++++------
 src/store.rs          |  5 ++---
 4 files changed, 33 insertions(+), 29 deletions(-)

diff --git a/src/cinnabar-helper.c b/src/cinnabar-helper.c
index 131e69668..8212594e4 100644
--- a/src/cinnabar-helper.c
+++ b/src/cinnabar-helper.c
@@ -528,19 +528,8 @@ static int count_refs(const char *refname, const struct object_id *oid,
 	return 0;
 }
 
-static void reset_metadata(void)
+static void init_metadata(struct commit *c)
 {
-	oidcpy(&metadata_oid, null_oid());
-	oidcpy(&changesets_oid, null_oid());
-	oidcpy(&manifests_oid, null_oid());
-	oidcpy(&hg2git_oid, null_oid());
-	oidcpy(&git2hg_oid, null_oid());
-	oidcpy(&files_meta_oid, null_oid());
-}
-
-static void init_metadata(void)
-{
-	struct commit *c;
 	struct commit_list *cl;
 	const char *msg, *body;
 	struct strbuf **flags, **f;
@@ -550,9 +539,13 @@ static void init_metadata(void)
 	struct replace_object *replace;
 	size_t count = 0;
 
-	c = lookup_commit_reference_by_name(METADATA_REF);
 	if (!c) {
-		reset_metadata();
+		oidcpy(&metadata_oid, null_oid());
+		oidcpy(&changesets_oid, null_oid());
+		oidcpy(&manifests_oid, null_oid());
+		oidcpy(&hg2git_oid, null_oid());
+		oidcpy(&git2hg_oid, null_oid());
+		oidcpy(&files_meta_oid, null_oid());
 		return;
 	}
 	oidcpy(&metadata_oid, &c->object.oid);
@@ -657,8 +650,10 @@ void dump_ref_updates(void);
 
 extern void reset_changeset_heads(void);
 
-void do_reload(int reset)
+void do_reload(struct object_id *oid)
 {
+	struct commit *c = NULL;
+
 	done_cinnabar();
 	hashmap_init(&git_tree_cache, oid_map_entry_cmp, NULL, 0);
 
@@ -668,11 +663,14 @@ void do_reload(int reset)
 
 	metadata_flags = 0;
 	reset_replace_map();
-	if (reset) {
-		reset_metadata();
+	if (oid) {
+		if (!is_null_oid(oid)) {
+			c = lookup_commit_reference(the_repository, oid);
+		}
 	} else {
-		init_metadata();
+		c = lookup_commit_reference_by_name(METADATA_REF);
 	}
+	init_metadata(c);
 	reset_changeset_heads();
 }
 
@@ -857,10 +855,12 @@ void init_cinnabar(const char *argv0)
 
 int init_cinnabar_2(void)
 {
+	struct commit *c;
 	if (nongit) {
 		return 0;
 	}
-	init_metadata();
+	c = lookup_commit_reference_by_name(METADATA_REF);
+	init_metadata(c);
 	hashmap_init(&git_tree_cache, oid_map_entry_cmp, NULL, 0);
 	return 1;
 }
diff --git a/src/cinnabar-helper.h b/src/cinnabar-helper.h
index 8cf2c9ca4..d1eddcfac 100644
--- a/src/cinnabar-helper.h
+++ b/src/cinnabar-helper.h
@@ -51,7 +51,7 @@ void create_git_tree(const struct object_id *tree_id,
                      struct object_id *result);
 
 void reset_manifest_heads(void);
-void do_reload(int);
+void do_reload(struct object_id *);
 unsigned int replace_map_size(void);
 
 const struct object_id *repo_lookup_replace_object(
diff --git a/src/main.rs b/src/main.rs
index 6a56cd1a5..10f00e0d8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -174,7 +174,7 @@ pub const FULL_VERSION: &str = git_version!(
 
 #[allow(improper_ctypes)]
 extern "C" {
-    pub fn do_reload(reset: c_int);
+    pub fn do_reload(metadata: *const object_id);
     fn do_cleanup(rollback: c_int);
 
     fn do_store_metadata(result: *mut object_id);
@@ -273,7 +273,7 @@ fn do_done_and_check(args: &[&[u8]]) -> bool {
                 .unwrap();
             transaction.commit().unwrap();
         }
-        do_reload(0);
+        do_reload(std::ptr::null());
     }
     do_check_files()
 }
@@ -839,11 +839,12 @@ extern "C" {
 }
 
 fn do_reclone() -> Result<(), String> {
-    unsafe {
+    let current_metadata_oid = unsafe {
         let current_metadata_oid = metadata_oid.clone();
-        do_reload(/* reset */ 1);
-        metadata_oid = current_metadata_oid;
-    }
+        do_reload(&object_id::default());
+        metadata_oid = current_metadata_oid.clone();
+        current_metadata_oid
+    };
 
     check_graft_refs();
 
@@ -942,6 +943,10 @@ fn do_reclone() -> Result<(), String> {
         Ok(())
     })
     .and_then(|()| {
+        unsafe {
+            metadata_oid = current_metadata_oid;
+        }
+
         do_done_and_check(&[])
             .then_some(())
             .ok_or_else(|| "Fatal error".to_string())?;
diff --git a/src/store.rs b/src/store.rs
index 5847f9719..a0f9573a6 100644
--- a/src/store.rs
+++ b/src/store.rs
@@ -51,7 +51,7 @@ use crate::progress::{progress_enabled, Progress};
 use crate::tree_util::{diff_by_path, Empty, ParseTree, RecurseTree};
 use crate::util::{FromBytes, ImmutBString, OsStrExt, ReadExt, SliceExt, ToBoxed, Transpose};
 use crate::xdiff::{apply, textdiff, PatchInfo};
-use crate::{check_enabled, do_reload, set_metadata_to, Checks, MetadataFlags};
+use crate::{check_enabled, do_reload, Checks};
 
 pub const REFS_PREFIX: &str = "refs/cinnabar/";
 pub const REPLACE_REFS_PREFIX: &str = "refs/cinnabar/replace/";
@@ -1807,9 +1807,8 @@ pub fn merge_metadata(git_url: Url, hg_url: Option<Url>, branch: Option<&[u8]>)
         }
     }
 
-    set_metadata_to(Some(metadata_cid), MetadataFlags::FORCE, "cinnabarclone").unwrap();
     unsafe {
-        do_reload(0);
+        do_reload(&object_id::from(metadata_cid));
     }
     true
 }