Prevent duplicate repos from being added. Fixes #473

The change to repo_add_dialog.py adds a check in the database
to see if the repo already exists, and blocks the ui with an
error message if so.
The change to repo_tab.py refactors the selector population logic
so that the selector stays in sync with the database and doesn't
leave the entry in the UI that triggers the crash.

src/vorta/views/repo_add_dialog.py

@@ -5,6 +5,7 @@ from vorta.utils import get_private_keys, get_asset, choose_file_dialog, borg_co
 from vorta.borg.init import BorgInitThread
 from vorta.borg.info import BorgInfoThread
 from vorta.views.utils import get_colored_icon
+from vorta.models import RepoModel
 
 uifile = get_asset('UI/repoadd.ui')
 AddRepoUI, AddRepoBase = uic.loadUiType(uifile)
@@ -117,6 +118,10 @@ class AddRepoWindow(AddRepoBase, AddRepoUI):
             self._set_status(self.tr('Please enter a valid repo URL or select a local path.'))
             return False
 
+        if RepoModel.get_or_none(RepoModel.url == self.values['repo_url']) is not None:
+            self._set_status(self.tr('This repo has already been added.'))
+            return False
+
         if self.__class__ == AddRepoWindow:
             if self.values['encryption'] != 'none':
                 if len(self.values['password']) < 8:

src/vorta/views/repo_tab.py

@@ -25,9 +25,7 @@ class RepoTab(RepoBase, RepoUI, BackupProfileMixin):
         self.repoSelector.addItem(self.tr('+ Initialize New Repository'), 'new')
         self.repoSelector.addItem(self.tr('+ Add Existing Repository'), 'existing')
         self.repoSelector.insertSeparator(3)
-        for repo in RepoModel.select():
-            self.repoSelector.addItem(repo.url, repo.id)
-
+        self.set_repos()
         self.repoSelector.currentIndexChanged.connect(self.repo_select_action)
         self.repoRemoveToolbutton.clicked.connect(self.repo_unlink_action)
 
@@ -64,6 +62,13 @@ class RepoTab(RepoBase, RepoUI, BackupProfileMixin):
         self.repoRemoveToolbutton.setIcon(get_colored_icon('unlink'))
         self.sshKeyToClipboardButton.setIcon(get_colored_icon('copy'))
 
+    def set_repos(self):
+        count = self.repoSelector.count()
+        for x in range(4, count):  # Repositories are listed after 4th entry in repoSelector
+            self.repoSelector.removeItem(4)
+        for repo in RepoModel.select():
+            self.repoSelector.addItem(repo.url, repo.id)
+
     def populate_from_profile(self):
         profile = self.profile()
         if profile.repo:
@@ -175,7 +180,7 @@ class RepoTab(RepoBase, RepoUI, BackupProfileMixin):
             profile.repo = new_repo.id
             profile.save()
 
-            self.repoSelector.addItem(new_repo.url, new_repo.id)
+            self.set_repos()
             self.repoSelector.setCurrentIndex(self.repoSelector.count() - 1)
             self.repo_added.emit()
             self.init_repo_stats()