Implement checkout of remote branches (#1516)

* Add remote branch submenu to context menu

* Checkout remote branch

* Update local libgit2-glib-1.0.vapi

* Correct action name

* Get remote branch checkout working

* Simplify

* Do not show Remote Branch option when no remote branches

* Revert to CheckoutStrategy.FORCE

* Actually checkout remote branch as head; DRY

* Warn if remote branch not found

* Confirm overwriting uncommitted changes when checking out branch

* Update POTFILES

* Split out confirmation dialog into another PR

* Construct local branch menu like remote one

* Consistent action names

* Fix set upstream

---------

Co-authored-by: Jeremy Wootten <jeremy@Proteus-EL07R6-9b3c42bb.localdomain>
Co-authored-by: Ryan Kornheisl <ryan@skarva.tech>

Author: 3 people

src/FolderManager/FileView.vala

@@ -32,7 +32,8 @@ public class Scratch.FolderManager.FileView : Code.Widgets.SourceList, Code.Pane
     public const string ACTION_DELETE = "delete";
     public const string ACTION_NEW_FILE = "new-file";
     public const string ACTION_NEW_FOLDER = "new-folder";
-    public const string ACTION_CHANGE_BRANCH = "change-branch";
+    public const string ACTION_CHECKOUT_LOCAL_BRANCH = "checkout-local-branch";
+    public const string ACTION_CHECKOUT_REMOTE_BRANCH = "checkout-remote-branch";
     public const string ACTION_CLOSE_FOLDER = "close-folder";
     public const string ACTION_CLOSE_OTHER_FOLDERS = "close-other-folders";
     public const string ACTION_SET_ACTIVE_PROJECT = "set-active-project";

src/FolderManager/ProjectFolderItem.vala

@@ -26,7 +26,8 @@ namespace Scratch.FolderManager {
 
         private static Icon added_icon;
         private static Icon modified_icon;
-        private SimpleAction change_branch_action;
+        private SimpleAction checkout_local_branch_action;
+        private SimpleAction checkout_remote_branch_action;
 
         public signal void closed ();
 
@@ -68,16 +69,21 @@ namespace Scratch.FolderManager {
                     );
                 }
 
-                change_branch_action.set_state (monitored_repo.branch_name);
+                checkout_local_branch_action.set_state (monitored_repo.branch_name);
             }
         }
 
         construct {
             monitored_repo = Scratch.Services.GitManager.get_instance ().add_project (this);
             notify["name"].connect (branch_or_name_changed);
             if (monitored_repo != null) {
-                change_branch_action = new SimpleAction.stateful (
-                    FileView.ACTION_CHANGE_BRANCH,
+                checkout_local_branch_action = new SimpleAction.stateful (
+                    FileView.ACTION_CHECKOUT_LOCAL_BRANCH,
+                    GLib.VariantType.STRING,
+                    ""
+                );
+                checkout_remote_branch_action = new SimpleAction.stateful (
+                    FileView.ACTION_CHECKOUT_REMOTE_BRANCH,
                     GLib.VariantType.STRING,
                     ""
                 );
@@ -86,7 +92,8 @@ namespace Scratch.FolderManager {
                 monitored_repo.file_status_change.connect (() => update_item_status (null));
                 monitored_repo.update_status_map ();
                 monitored_repo.branch_changed ();
-                change_branch_action.activate.connect (handle_change_branch_action);
+                checkout_local_branch_action.activate.connect (handle_checkout_local_branch_action);
+                checkout_remote_branch_action.activate.connect (handle_checkout_remote_branch_action);
             }
         }
 
@@ -315,20 +322,44 @@ namespace Scratch.FolderManager {
 
         protected GLib.MenuItem create_submenu_for_branch () {
             // Ensures that action for relevant project is being used
-            view.actions.add_action (change_branch_action);
-
-            GLib.Menu branch_selection_menu = new GLib.Menu ();
-            foreach (unowned var branch_name in monitored_repo.get_local_branches ()) {
-                branch_selection_menu.append (
-                    branch_name,
-                    GLib.Action.print_detailed_name (
-                        FileView.ACTION_PREFIX + FileView.ACTION_CHANGE_BRANCH,
-                        branch_name
-                    )
-                );
+            view.actions.add_action (checkout_local_branch_action);
+            view.actions.add_action (checkout_remote_branch_action);
+
+            unowned var local_branches = monitored_repo.get_local_branches ();
+            var local_branch_submenu = new Menu ();
+            var local_branch_menu = new Menu ();
+            if (local_branches.length () > 0) {
+                local_branch_submenu.append_submenu (_("Local"), local_branch_menu);
+                foreach (unowned var branch_name in local_branches) {
+                    local_branch_menu.append (
+                        branch_name,
+                        GLib.Action.print_detailed_name (
+                            FileView.ACTION_PREFIX + FileView.ACTION_CHECKOUT_LOCAL_BRANCH,
+                            branch_name
+                        )
+                    );
+                }
             }
 
 
+            unowned var remote_branches = monitored_repo.get_remote_branches ();
+            var remote_branch_submenu = new Menu ();
+            var remote_branch_menu = new Menu ();
+            if (remote_branches.length () > 0) {
+                remote_branch_submenu.append_submenu (_("Remote"), remote_branch_menu);
+                foreach (unowned var branch_name in remote_branches) {
+                    remote_branch_menu.append (
+                        branch_name,
+                        GLib.Action.print_detailed_name (
+                            FileView.ACTION_PREFIX + FileView.ACTION_CHECKOUT_REMOTE_BRANCH,
+                            branch_name
+                        )
+                    );
+                }
+
+
+            }
+
             var new_branch_item = new GLib.MenuItem (
                 _("New Branch…"),
                 GLib.Action.print_detailed_name (
@@ -351,22 +382,36 @@ namespace Scratch.FolderManager {
             bottom_section.append_item (new_branch_item);
 
             var menu = new GLib.Menu ();
-            menu.append_section (null, branch_selection_menu);
+            menu.append_section (null, local_branch_submenu);
+            menu.append_section (null, remote_branch_submenu);
             menu.append_section (null, bottom_section);
 
             var menu_item = new GLib.MenuItem.submenu (_("Branch"), menu);
             return menu_item;
         }
 
-        private void handle_change_branch_action (GLib.Variant? parameter) {
-            var branch_name = parameter.get_string ();
+        private void handle_checkout_local_branch_action (GLib.Variant? param) {
+            var branch_name = param != null ? param.get_string () : "";
             try {
                 monitored_repo.change_local_branch (branch_name);
             } catch (GLib.Error e) {
                 warning ("Failed to change branch to %s. %s", branch_name, e.message);
             }
         }
 
+        private void handle_checkout_remote_branch_action (GLib.Variant? param) {
+            var branch_name = param != null ? param.get_string () : "";
+            if (branch_name == "") {
+                return;
+            }
+
+            try {
+                monitored_repo.checkout_remote_branch (branch_name);
+            } catch (GLib.Error e) {
+                warning ("Failed to change branch to %s. %s", branch_name, e.message);
+            }
+        }
+
         public void update_item_status (FolderItem? start_folder) {
             if (monitored_repo == null) {
                 debug ("Ignore non-git folders");

src/Services/MonitoredRepository.vala

@@ -29,6 +29,7 @@ namespace Scratch.Services {
     }
 
     public class MonitoredRepository : Object {
+        public const string ORIGIN_PREFIX = "origin/";
         public Ggit.Repository git_repo { get; set construct; }
         public string branch_name {
             get {
@@ -67,6 +68,8 @@ namespace Scratch.Services {
         // Need to use nullable status in order to pass Flatpak CI.
         private Gee.HashMap<string, Ggit.StatusFlags?> file_status_map;
 
+        private List<Ggit.Ref> remote_branch_ref_list;
+
         public Gee.Set<Gee.Map.Entry<string, Ggit.StatusFlags?>> non_current_entries {
             owned get {
                 return file_status_map.entries;
@@ -97,6 +100,8 @@ namespace Scratch.Services {
                 Ggit.StatusShow.INDEX_AND_WORKDIR,
                 null
             );
+
+            remote_branch_ref_list = new List<Ggit.Ref> ();
         }
 
         public MonitoredRepository (Ggit.Repository _git_repo) {
@@ -168,6 +173,28 @@ namespace Scratch.Services {
             return branches;
         }
 
+        public unowned List<string> get_remote_branches () {
+            unowned List<string> branch_names = null;
+            try {
+                var branch_enumerator = git_repo.enumerate_branches (Ggit.BranchType.REMOTE);
+
+                foreach (Ggit.Ref branch_ref in branch_enumerator) {
+                    var remote_name = branch_ref.get_shorthand ();
+                    if (!remote_name.has_suffix ("HEAD") &&
+                        !has_local_branch_name (remote_name.substring (ORIGIN_PREFIX.length))) {
+
+                        branch_names.append (branch_ref.get_shorthand ());
+                    }
+
+                    remote_branch_ref_list.append (branch_ref);
+                }
+            } catch (Error e) {
+                warning ("Could not enumerate local branches %s", e.message);
+            }
+
+            return branch_names;
+        }
+
         public bool has_local_branch_name (string name) {
             try {
                 git_repo.lookup_branch (name, Ggit.BranchType.LOCAL);
@@ -186,11 +213,47 @@ namespace Scratch.Services {
             return true;
         }
 
-        public void change_local_branch (string new_branch_name) throws Error {
+        public void change_local_branch (string new_branch_name) throws Error
+        requires (!new_branch_name.has_prefix (ORIGIN_PREFIX)) {
+
             var branch = git_repo.lookup_branch (new_branch_name, Ggit.BranchType.LOCAL);
             checkout_branch (branch);
         }
 
+        public void checkout_remote_branch (string target_shorthand) throws Error
+        requires (target_shorthand.has_prefix (ORIGIN_PREFIX)) {
+
+            Ggit.Ref? branch_ref;
+            //Assume list is up to date as this is called from context menu
+            unowned var list_pointer = remote_branch_ref_list.first ();
+            while (list_pointer.data != null &&
+                   list_pointer.data.get_shorthand () != target_shorthand) {
+
+                list_pointer = list_pointer.next;
+            }
+
+            branch_ref = list_pointer.data;
+            if (branch_ref == null) {
+                var dialog = new Granite.MessageDialog.with_image_from_icon_name (
+                    _("Remote Branch '%s' not found").printf (target_shorthand),
+                    _("The requested branch was not found in any remote linked to this repository"),
+                    "dialog-warning"
+                ) {
+                    modal = true
+                };
+
+                dialog.response.connect (() => {dialog.destroy ();});
+                dialog.present ();
+                return;
+            }
+
+            var commit = branch_ref.lookup ();
+            var local_name = target_shorthand.substring (ORIGIN_PREFIX.length);
+            var local_branch = git_repo.create_branch (local_name, commit, NONE) as Ggit.Branch;
+            checkout_branch (local_branch);
+            local_branch.set_upstream (target_shorthand);
+        }
+
         private void checkout_branch (Ggit.Branch new_head_branch, bool confirm = true) {
             var new_branch_name = "";
             try {

vapi/libgit2-glib-1.0.vapi

@@ -77,6 +77,7 @@ namespace Ggit {
 		public Ggit.Ref? get_upstream () throws GLib.Error;
 		public bool is_head () throws GLib.Error;
 		public Ggit.Branch? move (string new_branch_name, Ggit.CreateFlags flags) throws GLib.Error;
+		public void set_upstream (string upstream_branch_name) throws GLib.Error;
 	}
 	[CCode (cheader_filename = "libgit2-glib/ggit.h", ref_function = "ggit_branch_enumerator_ref", type_id = "ggit_branch_enumerator_get_type ()", unref_function = "ggit_branch_enumerator_unref")]
 	[Compact]