Add failure tests for stealing subgraphs. Minor fix in pipeline validation. (NVIDIA#5518)

Signed-off-by: Michal Zientkiewicz <michalz@nvidia.com>

Author: mzient

dali/python/nvidia/dali/pipeline.py

@@ -722,7 +722,9 @@ def __exit__(self, type, value, traceback):
     def _require_unique_names(self):
         ops_by_name = {}
         for op in self._ops:
-            ops = ops_by_name.get(op.name, [])
+            ops = ops_by_name.get(op.name, None)
+            if ops is None:
+                ops = ops_by_name[op.name] = []
             ops.append(op)
         duplicate = {}
         foreign = False

dali/test/python/checkpointing/test_dali_checkpointing.py

@@ -36,6 +36,8 @@
 from nvidia.dali.auto_aug import trivial_augment as ta
 from reader.test_numpy import is_gds_supported
 from nose.plugins.attrib import attr
+from nose_utils import assert_raises
+
 
 reader_signed_off = create_sign_off_decorator()
 random_signed_off = create_sign_off_decorator()
@@ -1185,6 +1187,23 @@ def pipeline():
     compare_pipelines(pipe2, pipe3, batch_size, 5)
 
 
+def test_unsupported_dangling_subgraph():
+    es = fn.external_source("asdf")
+
+    @pipeline_def(batch_size=1, num_threads=1, device_id=None, enable_checkpointing=True)
+    def pipe(arg):
+        return arg + 0
+
+    p = pipe(es)
+
+    with assert_raises(
+        RuntimeError,
+        glob="The pipeline does not support checkpointing*"
+        "because it contains operator*outside the pipeline*",
+    ):
+        p.build()
+
+
 unsupported_readers = [
     "experimental.readers.fits",
 ]

dali/test/python/test_pipeline.py

@@ -2204,3 +2204,21 @@ def test_regression_without_current_pipeline2():
     data = fn.external_source(source=[1, 2, 3], batch=False, cycle=True)
     pipe.set_outputs(data.gpu())
     pipe.build()
+
+
+def test_subgraph_stealing():
+    p1 = Pipeline(batch_size=1, device_id=None, num_threads=1)
+    p2 = Pipeline(batch_size=1, device_id=None, num_threads=1)
+    with p1:
+        es1 = fn.external_source(source=[1, 2, 3], batch=False)
+        x = es1 + 1
+        p1.set_outputs(x)
+    with p2:
+        es2 = fn.external_source(source=[1, 2, 3], batch=False)
+        p2.set_outputs(x + es2)
+    p1.build()
+    with assert_raises(
+        RuntimeError,
+        glob="The pipeline is invalid because it contains operators with non-unique names",
+    ):
+        p2.build()