diff --git a/ognibuild/buildsystem.py b/ognibuild/buildsystem.py
index 60309e6..75a024b 100644
--- a/ognibuild/buildsystem.py
+++ b/ognibuild/buildsystem.py
@@ -114,7 +114,11 @@ class SetupPy(BuildSystem):
     def __init__(self, path):
         self.path = path
         from distutils.core import run_setup
-        self.result = run_setup(os.path.abspath(path), stop_after="init")
+        try:
+            self.result = run_setup(os.path.abspath(path), stop_after="init")
+        except RuntimeError as e:
+            logging.warning('Unable to load setup.py metadata: %s', e)
+            self.result = None
 
     def __repr__(self):
         return "%s(%r)" % (type(self).__name__, self.path)
@@ -137,9 +141,9 @@ class SetupPy(BuildSystem):
             logging.debug("Reference to setuptools-scm found, installing.")
             resolver.install(
                 [
-                    PythonPackageRequirement("setuptools-scm"),
+                    PythonPackageRequirement("setuptools_scm"),
                     BinaryRequirement("git"),
-                    BinaryRequirement("mercurial"),
+                    BinaryRequirement("hg"),
                 ]
             )
 
@@ -181,6 +185,8 @@ class SetupPy(BuildSystem):
                 fixers)
 
     def get_declared_dependencies(self):
+        if self.result is None:
+            raise NotImplementedError
         for require in self.result.get_requires():
             yield "build", PythonPackageRequirement(require)
         # Not present for distutils-only packages
@@ -193,6 +199,8 @@ class SetupPy(BuildSystem):
                 yield "test", PythonPackageRequirement(require)
 
     def get_declared_outputs(self):
+        if self.result is None:
+            raise NotImplementedError
         for script in self.result.scripts or []:
             yield UpstreamOutput("binary", os.path.basename(script))
         entry_points = getattr(self.result, 'entry_points', None) or {}
diff --git a/ognibuild/debian/fix_build.py b/ognibuild/debian/fix_build.py
index 1ccc9bf..01c7d36 100644
--- a/ognibuild/debian/fix_build.py
+++ b/ognibuild/debian/fix_build.py
@@ -48,9 +48,11 @@ from debmutate.reformatting import (
     FormattingUnpreservable,
     GeneratedFile,
 )
-from lintian_brush import (
-    reset_tree,
-)
+try:
+    from breezy.workspace import reset_tree
+except ImportError:
+    from lintian_brush import reset_tree
+
 from lintian_brush.changelog import (
     add_changelog_entry,
 )
diff --git a/ognibuild/dist.py b/ognibuild/dist.py
index 2349fe7..e507f18 100644
--- a/ognibuild/dist.py
+++ b/ognibuild/dist.py
@@ -103,7 +103,7 @@ class DistCatcher(object):
             logging.info("No tarballs found in dist directory.")
 
         parent_directory = os.path.dirname(self.export_directory)
-        diff = set(os.listdir(parent_directory)) - set([subdir])
+        diff = set(os.listdir(parent_directory)) - set([self.export_directory])
         if len(diff) == 1:
             fn = diff.pop()
             logging.info("Found tarball %s in parent directory.", fn)
diff --git a/ognibuild/session/plain.py b/ognibuild/session/plain.py
index 084fa1b..749bf49 100644
--- a/ognibuild/session/plain.py
+++ b/ognibuild/session/plain.py
@@ -44,3 +44,6 @@ class PlainSession(Session):
 
     def scandir(self, path):
         return os.scandir(path)
+
+    def chdir(self, path):
+        os.chdir(path)