drop "support" for legacy tree config

The tree-level conflicts have worked well in practice and we don't
want to allow users to use legacy trees for new commits. We don't
really support legacy trees very well since 0590f8bece anyway.

cli/src/config/misc.toml

@@ -5,9 +5,6 @@ amend = ["squash"]
 co = ["checkout"]
 unamend = ["unsquash"]
 
-[format]
-tree-level-conflicts = true
-
 [ui]
 # TODO: delete ui.allow-filesets in jj 0.26+
 allow-filesets = true

lib/src/git_backend.rs

@@ -124,8 +124,6 @@ pub struct GitBackend {
     empty_tree_id: TreeId,
     extra_metadata_store: TableStore,
     cached_extra_metadata: Mutex<Option<Arc<ReadonlyTable>>>,
-    /// Whether tree of imported commit should be promoted to non-legacy format.
-    imported_commit_uses_tree_conflict_format: bool,
 }
 
 impl GitBackend {
@@ -133,11 +131,7 @@ impl GitBackend {
         "git"
     }
 
-    fn new(
-        base_repo: gix::ThreadSafeRepository,
-        extra_metadata_store: TableStore,
-        imported_commit_uses_tree_conflict_format: bool,
-    ) -> Self {
+    fn new(base_repo: gix::ThreadSafeRepository, extra_metadata_store: TableStore) -> Self {
         let repo = Mutex::new(base_repo.to_thread_local());
         let root_commit_id = CommitId::from_bytes(&[0; HASH_LENGTH]);
         let root_change_id = ChangeId::from_bytes(&[0; CHANGE_ID_LENGTH]);
@@ -150,7 +144,6 @@ impl GitBackend {
             empty_tree_id,
             extra_metadata_store,
             cached_extra_metadata: Mutex::new(None),
-            imported_commit_uses_tree_conflict_format,
         }
     }
 
@@ -166,7 +159,7 @@ impl GitBackend {
             gix_open_opts_from_settings(settings),
         )
         .map_err(GitBackendInitError::InitRepository)?;
-        Self::init_with_repo(settings, store_path, git_repo_path, git_repo)
+        Self::init_with_repo(store_path, git_repo_path, git_repo)
     }
 
     /// Initializes backend by creating a new Git repo at the specified
@@ -190,7 +183,7 @@ impl GitBackend {
         )
         .map_err(GitBackendInitError::InitRepository)?;
         let git_repo_path = workspace_root.join(".git");
-        Self::init_with_repo(settings, store_path, &git_repo_path, git_repo)
+        Self::init_with_repo(store_path, &git_repo_path, git_repo)
     }
 
     /// Initializes backend with an existing Git repo at the specified path.
@@ -210,11 +203,10 @@ impl GitBackend {
             gix_open_opts_from_settings(settings),
         )
         .map_err(GitBackendInitError::OpenRepository)?;
-        Self::init_with_repo(settings, store_path, git_repo_path, git_repo)
+        Self::init_with_repo(store_path, git_repo_path, git_repo)
     }
 
     fn init_with_repo(
-        settings: &UserSettings,
         store_path: &Path,
         git_repo_path: &Path,
         git_repo: gix::ThreadSafeRepository,
@@ -244,11 +236,7 @@ impl GitBackend {
                 .map_err(GitBackendInitError::Path)?;
         };
         let extra_metadata_store = TableStore::init(extra_path, HASH_LENGTH);
-        Ok(GitBackend::new(
-            git_repo,
-            extra_metadata_store,
-            settings.use_tree_conflict_format(),
-        ))
+        Ok(GitBackend::new(git_repo, extra_metadata_store))
     }
 
     pub fn load(
@@ -271,11 +259,7 @@ impl GitBackend {
         )
         .map_err(GitBackendLoadError::OpenRepository)?;
         let extra_metadata_store = TableStore::load(store_path.join("extra"), HASH_LENGTH);
-        Ok(GitBackend::new(
-            repo,
-            extra_metadata_store,
-            settings.use_tree_conflict_format(),
-        ))
+        Ok(GitBackend::new(repo, extra_metadata_store))
     }
 
     fn lock_git_repo(&self) -> MutexGuard<'_, gix::Repository> {
@@ -348,6 +332,14 @@ impl GitBackend {
     pub fn import_head_commits<'a>(
         &self,
         head_ids: impl IntoIterator<Item = &'a CommitId>,
+    ) -> BackendResult<()> {
+        self.import_head_commits_with_tree_conflicts(head_ids, true)
+    }
+
+    fn import_head_commits_with_tree_conflicts<'a>(
+        &self,
+        head_ids: impl IntoIterator<Item = &'a CommitId>,
+        uses_tree_conflict_format: bool,
     ) -> BackendResult<()> {
         let head_ids: HashSet<&CommitId> = head_ids
             .into_iter()
@@ -377,7 +369,7 @@ impl GitBackend {
             &mut mut_table,
             &table_lock,
             &head_ids,
-            self.imported_commit_uses_tree_conflict_format,
+            uses_tree_conflict_format,
         )?;
         self.save_extra_metadata_table(mut_table, &table_lock)
     }
@@ -1491,14 +1483,7 @@ mod tests {
     #[test_case(false; "legacy tree format")]
     #[test_case(true; "tree-level conflict format")]
     fn read_plain_git_commit(uses_tree_conflict_format: bool) {
-        let settings = {
-            let config = config::Config::builder()
-                .set_override("format.tree-level-conflicts", uses_tree_conflict_format)
-                .unwrap()
-                .build()
-                .unwrap();
-            UserSettings::from_config(config)
-        };
+        let settings = user_settings();
         let temp_dir = testutils::new_temp_dir();
         let store_path = temp_dir.path();
         let git_repo_path = temp_dir.path().join("git");
@@ -1561,7 +1546,9 @@ mod tests {
         let backend = GitBackend::init_external(&settings, store_path, git_repo.path()).unwrap();
 
         // Import the head commit and its ancestors
-        backend.import_head_commits([&commit_id2]).unwrap();
+        backend
+            .import_head_commits_with_tree_conflicts([&commit_id2], uses_tree_conflict_format)
+            .unwrap();
         // Ref should be created only for the head commit
         let git_refs = backend
             .open_git_repo()

lib/src/repo.rs

@@ -155,7 +155,7 @@ impl ReadonlyRepo {
         let backend = backend_initializer(user_settings, &store_path)?;
         let backend_path = store_path.join("type");
         fs::write(&backend_path, backend.name()).context(&backend_path)?;
-        let store = Store::new(backend, signer, user_settings.use_tree_conflict_format());
+        let store = Store::new(backend, signer);
         let repo_settings = user_settings.with_repo(&repo_path).unwrap();
 
         let op_store_path = repo_path.join("op_store");
@@ -632,7 +632,6 @@ impl RepoLoader {
         let store = Store::new(
             store_factories.load_backend(user_settings, &repo_path.join("store"))?,
             Signer::from_settings(user_settings)?,
-            user_settings.use_tree_conflict_format(),
         );
         let repo_settings = user_settings.with_repo(repo_path).unwrap();
         let op_store =

lib/src/settings.rs

@@ -147,12 +147,6 @@ impl UserSettings {
         self.rng.clone()
     }
 
-    pub fn use_tree_conflict_format(&self) -> bool {
-        self.config
-            .get_bool("format.tree-level-conflicts")
-            .unwrap_or(false)
-    }
-
     pub fn user_name(&self) -> String {
         self.config.get_string("user.name").unwrap_or_default()
     }

lib/src/store.rs

@@ -44,7 +44,6 @@ pub struct Store {
     signer: Signer,
     commit_cache: RwLock<HashMap<CommitId, Arc<backend::Commit>>>,
     tree_cache: RwLock<HashMap<(RepoPathBuf, TreeId), Arc<backend::Tree>>>,
-    use_tree_conflict_format: bool,
 }
 
 impl Debug for Store {
@@ -56,17 +55,12 @@ impl Debug for Store {
 }
 
 impl Store {
-    pub fn new(
-        backend: Box<dyn Backend>,
-        signer: Signer,
-        use_tree_conflict_format: bool,
-    ) -> Arc<Self> {
+    pub fn new(backend: Box<dyn Backend>, signer: Signer) -> Arc<Self> {
         Arc::new(Store {
             backend,
             signer,
             commit_cache: Default::default(),
             tree_cache: Default::default(),
-            use_tree_conflict_format,
         })
     }
 
@@ -78,11 +72,6 @@ impl Store {
         &self.signer
     }
 
-    /// Whether new tree should be written using the tree-level format.
-    pub fn use_tree_conflict_format(&self) -> bool {
-        self.use_tree_conflict_format
-    }
-
     pub fn get_copy_records(
         &self,
         paths: Option<&[RepoPathBuf]>,