depcheck: don't litter temporary files on error

When a multiprocessing.Pool is garbage collected or __exit__ed, it
calls the terminate method. In that case, temporary files are not
cleaned up. This happens for example, when an exception is raised in one
of the workers. Thus we close and join the pool explicitly.

1 files changed, 21 insertions, 5 deletions

diff --git a/depcheck.py b/depcheck.py
index 743a09d..e417c72 100755
--- a/depcheck.py
+++ b/depcheck.py
@@ -437,6 +437,18 @@ def main_docheck(mirror, architecture):
     return (architecture, check_bdsat(mirror, architecture))
 
 
+class SequentialPool:
+    """Sequential variant of multiprocessing.Pool for debugging."""
+    def __enter__(self):
+        return self
+    def __exit__(self, *args):
+        pass
+    def close(self):
+        pass
+    def join(self):
+        pass
+    imap_unordered = map
+
 def main():
     argp = argparse.ArgumentParser()
     argp.add_argument('-m', '--mirror',
@@ -457,11 +469,15 @@ def main():
         return
     print("checking %s" % " ".join(sorted(archs)))
     now = datetime.datetime.utcnow().replace(microsecond=0)
-    mapper = multiprocessing.Pool().imap_unordered if args.parallel else map
-    for architecture, state in mapper(functools.partial(main_docheck, mirror),
-                                      archs):
-        print("update %s" % architecture)
-        update_depcheck(mirror, db, now, architecture, state)
+    with multiprocessing.Pool() if args.parallel else SequentialPool() as pool:
+        docheck = functools.partial(main_docheck, mirror)
+        try:
+            for architecture, state in pool.imap_unordered(docheck, archs):
+                print("update %s" % architecture)
+                update_depcheck(mirror, db, now, architecture, state)
+        finally:
+            pool.close()
+            pool.join()
 
 if __name__ == "__main__":
     main()