source.py: Consider workspaced sources with missing content inconsistent

Avoid trying to calculate cache keys and then running into an error
by just considering workspaces with missing content to be inconsistent.

This fixes issue #80

1 files changed, 13 insertions, 2 deletions

diff --git a/buildstream/source.py b/buildstream/source.py
index a4402963e..bb6121995 100644
--- a/buildstream/source.py
+++ b/buildstream/source.py
@@ -199,6 +199,17 @@ class Source(Plugin):
     def _get_consistency(self, recalculate=False):
         if recalculate or self.__consistency is None:
             self.__consistency = self.get_consistency()
+
+            if self._has_workspace() and \
+               self.__consistency > Consistency.INCONSISTENT:
+
+                # A workspace is considered inconsistent in the case
+                # that it's directory went missing
+                #
+                fullpath = os.path.join(self.get_project().directory, self.__workspace)
+                if not os.path.exists(fullpath):
+                    self.__consistency = Consistency.INCONSISTENT
+
         return self.__consistency
 
     # Bump local cached consistency state, this is done from
@@ -328,11 +339,11 @@ class Source(Plugin):
 
         # Return a list of (relative filename, sha256 digest) tuples, a sorted list
         # has already been returned by list_relative_paths()
-        return [(relpath, sha256sum(fullpath)) for relpath, fullpath in filelist]
+        return [(relpath, _sha256sum(fullpath)) for relpath, fullpath in filelist]
 
 
 # Get the sha256 sum for the content of a file
-def sha256sum(filename):
+def _sha256sum(filename):
 
     # If it's a directory or symlink, just return 0 string
     if os.path.isdir(filename) or os.path.islink(filename):