fix: SyncDirectory Prediction

Add a check to the SyncDirectory component for the target directory.

The SyncDirectory component `verify()` stage fails when the target
directory does not exist yet, because it uses rsync to determine if there
is a diff between left and right. In cases where the target directory
is part of the deployment and has thusly not been created yet, this
leads to unexpected errors.

CHANGES.md

@@ -8,6 +8,8 @@
   bubbled incorrectly and caused spurious deployment errors.
 - Add new `rsync-ext` repository type which uses an external rsync
   binary for repository synchronisation.
+- Fix bug where the SyncDirectory component errors out because the target directory
+  does not exist yet.
 
 
 ## 2.4rc1 (2023-09-12)

src/batou/lib/file.py

@@ -204,6 +204,9 @@ def exclude_arg(self):
         return " ".join("--exclude '{}'".format(x) for x in self.exclude) + " "
 
     def verify(self):
+        if not os.path.isdir(self.path):
+            raise batou.UpdateNeeded()
+
         stdout, stderr = self.cmd(
             "rsync {} {}{}/ {}".format(
                 self.verify_opts, self.exclude_arg, self.source, self.path