diff --git a/tensorflow_probability/python/mcmc/hmc.py b/tensorflow_probability/python/mcmc/hmc.py
index be18bd614b..0de152454b 100644
--- a/tensorflow_probability/python/mcmc/hmc.py
+++ b/tensorflow_probability/python/mcmc/hmc.py
@@ -134,7 +134,7 @@ def step_size_simple_update_fn(step_size_var, kernel_results):
             tf.log(target_rate), log_mean_accept_ratio.dtype),
         -decrement_multiplier / (1. + decrement_multiplier),
         increment_multiplier)
-
+    a = True
     def build_assign_op():
       if mcmc_util.is_list_like(step_size_var):
         return [
diff --git a/tensorflow_probability/python/mcmc/hmc_test.py b/tensorflow_probability/python/mcmc/hmc_test.py
index d1eba9ef8e..61dfc57c55 100644
--- a/tensorflow_probability/python/mcmc/hmc_test.py
+++ b/tensorflow_probability/python/mcmc/hmc_test.py
@@ -40,6 +40,7 @@
 def run_in_graph_mode_only(__unused__=None, config=None, use_gpu=True):  # pylint: disable=invalid-name,unused-argument
   """Execute the decorated test in graph mode only."""
   assert not __unused__, 'Add () after run_in_graph_mode_only.'
+  b = False
   def decorator(f):
     def decorated(self, **kwargs):
       with context.graph_mode():
diff --git a/testing/oss_lints.sh b/testing/oss_lints.sh
index 364bb9ca0c..afc9dc9512 100755
--- a/testing/oss_lints.sh
+++ b/testing/oss_lints.sh
@@ -28,18 +28,20 @@ if [[ ${SHARD} != 0 ]]; then
 fi
 
 get_changed_py_files() {
-  # grep --quiet forces exit status 0 even if no matches are found
+  # Need to fetch the base branch in case it is not master.
+  git remote set-branches --add origin ${TRAVIS_BRANCH}
+  git fetch --depth=20 --quiet
   git diff \
       --name-only \
-      --diff-filter=AM ${TRAVIS_BRANCH}...HEAD \
-    | grep --quiet '^tensorflow_probability.*\.py$'
+      --diff-filter=AM origin/${TRAVIS_BRANCH}...HEAD \
+    | grep '^tensorflow_probability.*\.py$' || true
 }
 
 # Run lints on added/changed python files.
 changed_py_files=$(get_changed_py_files)
 if [[ -n "${changed_py_files}" ]]; then
   echo "Running pylint on ${changed_py_files}"
-  pylint -j2 --rcfile=testing/pylintrc ${changed_py_files})
+  pylint -j2 --rcfile=testing/pylintrc ${changed_py_files}
 else
   echo "No files to lint."
 fi
diff --git a/testing/oss_tests.sh b/testing/oss_tests.sh
index c3df3591dd..e7f7c1efe1 100755
--- a/testing/oss_tests.sh
+++ b/testing/oss_tests.sh
@@ -40,8 +40,11 @@ shard_tests=$(bazel query 'tests(//tensorflow_probability/...)' |
 #     (short, moderate, long or eternal)
 #   --test_tag_filters -- skip tests whose 'tags' arg (if present) includes any
 #     of the comma-separated entries
+#   --action_env -- specify environment vars to pass through to action
+#     environment. (We need these in order to run inside a virtualenv.)
+#     See https://github.com/bazelbuild/bazel/issues/6648 and b/121259040.
 echo "${shard_tests}" | xargs bazel test --copt=-O3 --copt=-march=native \
-  --noincompatible_strict_action_env \
   --test_tag_filters=-gpu,-requires-gpu-sm35 \
   --test_timeout 300,450,1200,3600 --build_tests_only \
+  --action_env=PATH --action_env=LD_LIBRARY_PATH \
   --test_output=errors