plugins/sources/patch.py: Removing unneeded check

The patch plugin was checking if the target directory exists, however
this is automatically guaranteed by the Source abstract class and
documented to be guaranteed as well.

Since this error cannot be caught by the plugin (it will be caught
in advance by the Source class), removing the check from patch.py.

1 files changed, 5 insertions, 7 deletions

diff --git a/buildstream/plugins/sources/patch.py b/buildstream/plugins/sources/patch.py
index 40fd106ec..a8a2da26c 100644
--- a/buildstream/plugins/sources/patch.py
+++ b/buildstream/plugins/sources/patch.py
@@ -80,14 +80,12 @@ class PatchSource(Source):
 
     def stage(self, directory):
         with self.timed_activity("Applying local patch: {}".format(self.path)):
-            if not os.path.isdir(directory):
-                raise SourceError(
-                    "Patch directory '{}' does not exist".format(directory),
-                    reason="patch-no-directory"
-                )
-            elif not os.listdir(directory):
-                raise SourceError("Empty patch directory '{}'".format(directory),
+
+            # Bail out with a comprehensive message if the target directory is empty
+            if not os.listdir(directory):
+                raise SourceError("Nothing to patch in directory '{}'".format(directory),
                                   reason="patch-no-files")
+
             strip_level_option = "-p{}".format(self.strip_level)
             self.call([self.host_patch, strip_level_option, "-i", self.fullpath, "-d", directory],
                       fail="Failed to apply patch {}".format(self.path))