Add support for setting default branch on repos

This commit adds support for setting the default branch on a repository.

* Add :default_branch to GitGud.Repo schema.
* Add <form> field to templates/repo/{edit.html.eex, new.html.eex}.
* Refactor GitRekt.RepoStorage.init/2 to set initial_head accordingly.
* Ensure that HEAD is updated when :default_branch field changes.
* Add workaround for views relying on @Head (which can be nil).

See #87 for more details.

Author: redrabbit

apps/gitgud/lib/gitgud/repo_storage.ex

@@ -23,7 +23,7 @@ defmodule GitGud.RepoStorage do
   """
   @spec init(Repo.t, boolean) :: {:ok, Git.repo} | {:error, term}
   def init(%Repo{} = repo, bare?) do
-    GenServer.call(RepoSupervisor.volume_name(__MODULE__, repo.volume), {:init, workdir(repo), bare?})
+    GenServer.call(RepoSupervisor.volume_name(__MODULE__, repo.volume), {:init, workdir(repo), bare?, repo.default_branch})
   end
 
   @doc """
@@ -93,8 +93,8 @@ defmodule GitGud.RepoStorage do
   end
 
   @impl true
-  def handle_call({:init, workdir, bare?}, _from, state) do
-    {:reply, Git.repository_init(workdir, bare?), state}
+  def handle_call({:init, workdir, bare?, initial_head}, _from, state) do
+    {:reply, Git.repository_init(workdir, bare?, initial_head), state}
   end
 
   def handle_call({:rename, old_workdir, new_workdir}, _from, state) do

apps/gitgud/lib/gitgud/schemas/repo.ex

@@ -9,6 +9,8 @@ defmodule GitGud.Repo do
 
   alias Ecto.Multi
 
+  alias GitRekt.GitAgent
+
   alias GitGud.DB
   alias GitGud.Issue
   alias GitGud.IssueLabel
@@ -25,6 +27,7 @@ defmodule GitGud.Repo do
     field :owner_login, :string
     field :name, :string
     field :public, :boolean, default: true
+    field :default_branch, :string, default: "main"
     field :volume, :string, autogenerate: {RepoStorage, :volume, []}
     field :description, :string
     has_many :issue_labels, IssueLabel, on_replace: :delete
@@ -41,6 +44,7 @@ defmodule GitGud.Repo do
     owner: User.t,
     name: binary,
     public: boolean,
+    default_branch: binary,
     volume: binary,
     description: binary,
     maintainers: [User.t],
@@ -217,8 +221,8 @@ defmodule GitGud.Repo do
   @spec changeset(t, map) :: Ecto.Changeset.t
   def changeset(%__MODULE__{} = repo, params \\ %{}) do
     repo
-    |> cast(params, [:name, :public, :description, :pushed_at])
-    |> validate_required([:name])
+    |> cast(params, [:name, :public, :description, :default_branch, :pushed_at])
+    |> validate_required([:name, :default_branch])
     |> validate_format(:name, ~r/^[a-zA-Z0-9_-]+$/)
     |> validate_length(:name, min: 3, max: 80)
     |> validate_exclusion(:name, ["repositories", "settings"])
@@ -285,6 +289,7 @@ defmodule GitGud.Repo do
   defp update_and_rename(changeset) do
     Multi.new()
     |> Multi.update(:repo, changeset)
+    |> Multi.run(:update_head, &update_head(&1, &2, changeset))
     |> Multi.run(:rename, &rename(&1, &2, changeset))
     |> DB.transaction()
   end
@@ -306,5 +311,19 @@ defmodule GitGud.Repo do
     else: RepoStorage.rename(changeset.data, repo)
   end
 
+  defp update_head(_db, %{repo: repo}, changeset) do
+    if branch = get_change(changeset, :default_branch) do
+      target = "refs/heads/" <> branch
+      case GitAgent.reference_create(repo, "HEAD", :symbolic, target, force: true) do
+        :ok ->
+          {:ok, target}
+        {:error, reason} ->
+          {:error, reason}
+      end
+    else
+      {:ok, false}
+    end
+  end
+
   defp cleanup(_db, %{repo: repo}), do: RepoStorage.cleanup(repo)
 end

apps/gitgud/priv/db/migrations/20221128203455_add_repository_default_branch_column.exs

@@ -0,0 +1,9 @@
+defmodule GitGud.DB.Migrations.AddRepositoryDefaultBranchColumn do
+  use Ecto.Migration
+
+  def change do
+    alter table("repositories") do
+      add :default_branch, :string, null: false, default: "main"
+    end
+  end
+end

apps/gitgud_web/lib/gitgud_web/controllers/codebase_controller.ex

@@ -290,6 +290,17 @@ defmodule GitGud.Web.CodebaseController do
             {:error, reason} ->
               {:error, reason}
           end
+        else
+          branches = Enum.sort_by(branches, &elem(&1, 2), {:desc, Date})
+          page = paginate(conn, branches)
+          slice = resolve_revisions_db(page.slice)
+          slice = Enum.map(slice, fn {ref, author, timestamp} -> {ref, author, timestamp, {0, 0}} end)
+          render(conn, "branch_list.html",
+            repo: repo,
+            repo_open_issue_count: IssueQuery.count_repo_issues(repo, status: :open),
+            head: head,
+            page: Map.put(page, :slice, slice)
+          )
         end
       end
     end || {:error, :not_found}
@@ -432,10 +443,14 @@ defmodule GitGud.Web.CodebaseController do
   end
 
   defp resolve_branches(agent) do
-    with {:ok, head} <- GitAgent.head(agent),
-         {:ok, branches} <- GitAgent.branches(agent),
+    with {:ok, branches} <- GitAgent.branches(agent),
          {:ok, branches} <- resolve_revisions(agent, branches) do
-      {:ok, {head, branches}}
+      case GitAgent.head(agent) do
+        {:ok, head} ->
+          {:ok, {head, branches}}
+        {:error, _reason} ->
+          {:ok, {nil, branches}}
+      end
     end
   end
 

apps/gitgud_web/lib/gitgud_web/live/branch_select_live.ex

@@ -109,21 +109,37 @@ defmodule GitGud.Web.BranchSelectLive do
   end
 
   defp resolve_references(agent) do
-    with {:ok, head} <- GitAgent.head(agent),
-         {:ok, refs} <- GitAgent.references(agent, with: :commit, target: :commit) do
-      refs = Enum.to_list(refs)
-      head_index = Enum.find_index(refs, &elem(&1, 0) == head)
-      {
-        :ok,
-        {
-          head,
-          refs
-          |> List.delete_at(head_index)
-          |> Enum.map(&map_reference_timestamp!(agent, &1))
-          |> Enum.sort_by(&elem(&1, 1), {:desc, NaiveDateTime})
-          |> Enum.map(&elem(&1, 0))
-        }
-      }
+    case GitAgent.references(agent, with: :commit, target: :commit) do
+      {:ok, refs} ->
+        case GitAgent.head(agent) do
+          {:ok, head} ->
+            refs = Enum.to_list(refs)
+            head_index = Enum.find_index(refs, &elem(&1, 0) == head)
+            {
+              :ok,
+              {
+                head,
+                refs
+                |> List.delete_at(head_index)
+                |> Enum.map(&map_reference_timestamp!(agent, &1))
+                |> Enum.sort_by(&elem(&1, 1), {:desc, NaiveDateTime})
+                |> Enum.map(&elem(&1, 0))
+              }
+            }
+          {:error, _reason} ->
+            {
+              :ok,
+              {
+                nil,
+                refs
+                |> Enum.map(&map_reference_timestamp!(agent, &1))
+                |> Enum.sort_by(&elem(&1, 1), {:desc, NaiveDateTime})
+                |> Enum.map(&elem(&1, 0))
+              }
+            }
+        end
+      {:error, reason} ->
+        {:error, reason}
     end
   end
 

apps/gitgud_web/lib/gitgud_web/live/branch_select_live.html.heex

@@ -40,10 +40,10 @@
           <a class={if @tab == :branch, do: "is-active"} phx-click="switch_tab" phx-value-tab="branch" phx-target={@myself}>Branches</a>
           <a class={if @tab == :tag, do: "is-active"} phx-click="switch_tab" phx-value-tab="tag" phx-target={@myself}>Tags</a>
         </p>
-        <%= if @tab == :branch do %>
-          <%= live_redirect to: Routes.codebase_path(@socket, @action, @repo.owner_login, @repo, @head, @tree_path), class: ["panel-block", @head.oid == @commit.oid && "is-active"] do %>
+        <%= if @tab == :branch && @head do %>
+          <%= live_redirect to: Routes.codebase_path(@socket, @action, @repo.owner_login, @repo, @repo.default_branch, @tree_path), class: ["panel-block", @head.oid == @commit.oid && "is-active"] do %>
             <div class="control">
-              <span class="head"><%= @head.name %></span>
+              <span class="head"><%= @repo.default_branch %></span>
               <span class="tag is-pulled-right">default</span>
             </div>
           <% end %>

apps/gitgud_web/lib/gitgud_web/live/commit_history_live.ex

@@ -58,7 +58,7 @@ defmodule GitGud.Web.CommitHistoryLive do
       {:ok, head} ->
         {:noreply, push_patch(socket, to: Routes.codebase_path(socket, :history, socket.assigns.repo.owner_login, socket.assigns.repo.name, head, Map.get(params, "path", [])))}
       {:error, error} ->
-        raise error
+        {:noreply, put_flash(socket, :error, error)}
     end
   end
 
@@ -114,11 +114,15 @@ defmodule GitGud.Web.CommitHistoryLive do
 
   defp resolve_revision_history(agent, commit, tree_path, cursor, limit) when is_struct(commit), do: resolve_history(agent, commit, tree_path, cursor, limit)
   defp resolve_revision_history(agent, rev_spec, tree_path, cursor, limit) do
-    with {:ok, head} <- GitAgent.head(agent),
-         {:ok, {obj, ref}} <- GitAgent.revision(agent, rev_spec),
+    with {:ok, {obj, ref}} <- GitAgent.revision(agent, rev_spec),
          {:ok, commit} <- GitAgent.peel(agent, obj, target: :commit),
          {:ok, {tree_entry_type, page}} <- resolve_history(agent, commit, tree_path, cursor, limit) do
-      {:ok, {head, ref, commit, tree_entry_type, page}}
+      case GitAgent.head(agent) do
+        {:ok, head} ->
+          {:ok, {head, ref, commit, tree_entry_type, page}}
+        {:error, _reason} ->
+          {:ok,{nil, ref, commit, tree_entry_type, page}}
+      end
     else
       {:error, reason} ->
         {:error, reason}

apps/gitgud_web/lib/gitgud_web/live/tree_browser_live.ex

@@ -87,17 +87,22 @@ defmodule GitGud.Web.TreeBrowserLive do
       if resolve_stats?,
         do: resolve_revision_tree_with_stats!(socket.assigns.agent, resolve_revision? && rev_spec || socket.assigns.commit, tree_path),
       else: resolve_revision_tree!(socket.assigns.agent, resolve_revision? && rev_spec || socket.assigns.commit, tree_path)
-    assigns = Map.update!(assigns, :tree_commit_info, &resolve_commit_info_db/1)
-    assigns = Map.update!(assigns, :tree_entries, &Enum.sort_by(&1, fn tree_entry -> tree_entry.name end))
-    assigns = Map.update!(assigns, :tree_entries, &Enum.map(&1, fn tree_entry -> {tree_entry, nil} end))
-    assigns =
-      if resolve_stats?,
-        do: Map.update(assigns, :stats, %{}, &Map.put(&1, :contributors, RepoQuery.count_contributors(socket.assigns.repo))),
-      else: assigns
 
-    socket
-    |> assign(rev_spec: rev_spec, tree_path: tree_path)
-    |> assign(assigns)
+    if assigns != %{} do
+      assigns = Map.update!(assigns, :tree_commit_info, &resolve_commit_info_db/1)
+      assigns = Map.update!(assigns, :tree_entries, &Enum.sort_by(&1, fn tree_entry -> tree_entry.name end))
+      assigns = Map.update!(assigns, :tree_entries, &Enum.map(&1, fn tree_entry -> {tree_entry, nil} end))
+      assigns =
+        if resolve_stats?,
+          do: Map.update(assigns, :stats, %{}, &Map.put(&1, :contributors, RepoQuery.count_contributors(socket.assigns.repo))),
+        else: assigns
+
+      socket
+      |> assign(rev_spec: rev_spec, tree_path: tree_path)
+      |> assign(assigns)
+    else
+      socket
+    end
   end
 
   defp assign_tree_commits_async(socket) do
@@ -118,23 +123,28 @@ defmodule GitGud.Web.TreeBrowserLive do
   end
 
   defp resolve_revision(agent, nil) do
-    with {:ok, false} <- GitAgent.empty?(agent),
-         {:ok, head} <- GitAgent.head(agent),
-         {:ok, commit} <- GitAgent.peel(agent, head) do
-      {:ok, {head, head, commit}}
-    else
-      {:ok, true} ->
-        {:error, "repository is empty"}
-      {:error, reason} ->
-        {:error, reason}
+    case GitAgent.head(agent) do
+      {:ok, head} ->
+        case GitAgent.peel(agent, head) do
+          {:ok, commit} ->
+            {:ok, {head, head, commit}}
+          {:error, reason} ->
+            {:error, reason}
+        end
+      {:error, _reason} ->
+        {:error, :invalid_head}
     end
   end
 
   defp resolve_revision(agent, rev_spec) do
-    with {:ok, head} <- GitAgent.head(agent),
-         {:ok, {obj, ref}} <- GitAgent.revision(agent, rev_spec),
+    with {:ok, {obj, ref}} <- GitAgent.revision(agent, rev_spec),
          {:ok, commit} <- GitAgent.peel(agent, obj, target: :commit) do
-      {:ok, {head, ref, commit}}
+      case GitAgent.head(agent) do
+        {:ok, head} ->
+          {:ok, {head, ref, commit}}
+        {:error, _reason} ->
+          {:ok, {nil, ref, commit}}
+      end
     end
   end
 
@@ -144,6 +154,8 @@ defmodule GitGud.Web.TreeBrowserLive do
         %{head: head, revision: ref || commit, commit: commit, tree_commit_info: commit_info, tree_entries: tree_entries, tree_readme: readme}
       {:ok, {commit_info, tree_entries, readme}} ->
         %{tree_commit_info: commit_info, tree_entries: tree_entries, tree_readme: readme}
+      {:error, :invalid_head} ->
+        %{}
       {:error, error} ->
         raise error
     end
@@ -166,6 +178,8 @@ defmodule GitGud.Web.TreeBrowserLive do
         %{head: head, revision: ref || commit, commit: commit, tree_commit_info: commit_info, tree_entries: tree_entries, tree_readme: readme, stats: stats}
       {:ok, {commit_info, tree_entries, readme, stats}} ->
         %{tree_commit_info: commit_info, tree_entries: tree_entries, tree_readme: readme, stats: stats}
+      {:error, :invalid_head} ->
+        %{}
       {:error, error} ->
         raise error
     end

apps/gitgud_web/lib/gitgud_web/live/tree_browser_live.html.heex

@@ -200,13 +200,13 @@
     git add README.md
     git commit -m "first commit"
     git remote add origin <%= Routes.codebase_url(@socket, :show, @repo.owner_login, @repo) %>.git
-    git push -u origin master
+    git push -u origin <%= @repo.default_branch %>
     </pre>
 
     <p>or push an existing repository from the command line</p>
     <pre>
     git remote add origin <%= Routes.codebase_url(@socket, :show, @repo.owner_login, @repo) %>.git
-    git push -u origin master
+    git push -u origin <%= @repo.default_branch %>
     </pre>
   </div>
 <% end %>