Skip to content

Fix warning message #36703

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Abacn merged 4 commits into from
Nov 3, 2025
Merged

Fix warning message #36703

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
6ff3ffd
Fix spammy warning message (and its formatting)
Abacn Oct 31, 2025
bf3d24d
address comments - make raw return a valid return
Abacn Oct 31, 2025
703b9e6
address comments
Abacn Nov 3, 2025
0feb9eb
add back tests
Abacn Nov 3, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
23 changes: 13 additions & 10 deletions sdks/python/apache_beam/transforms/core.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1507,25 +1507,28 @@ def _check_fn_use_yield_and_return(fn):
source_code = _get_function_body_without_inners(fn)
has_yield = False
has_return = False
return_none_warning = (
"No iterator is returned by the process method in %s.",
fn.__self__.__class__)
has_return_none = False
for line in source_code.split("\n"):
lstripped_line = line.lstrip()
if lstripped_line.startswith("yield ") or lstripped_line.startswith(
"yield("):
has_yield = True
if lstripped_line.startswith("return ") or lstripped_line.startswith(
elif lstripped_line.rstrip() == "return":
has_return_none = True
Copy link
Contributor

@damccorm damccorm Oct 31, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Maybe we can even skip this case? It seems like the only potentially problematic case is when they're expecting None to be processed downstream, in this case I think they probably have correct expectations

Copy link
Contributor Author

@Abacn Abacn Oct 31, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

yeah, updated. now both "return" and "return sth" will go to "has_return" (we still need to track all return statements to issue warning in the case both yield and return are used)

elif lstripped_line.startswith("return ") or lstripped_line.startswith(
"return("):
has_return = True
if lstripped_line.startswith(
"return None") or lstripped_line.rstrip() == "return":
_LOGGER.warning(return_none_warning)
if lstripped_line.startswith("return None"):
has_return_none = True
else:
Copy link
Contributor

@damccorm damccorm Oct 31, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think we can get rid of this else and always set has_return to True here (related to comment about condition below)

Copy link
Contributor Author

@Abacn Abacn Nov 3, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

done

has_return = True
if has_yield and has_return:
return True

if not has_yield and not has_return:
_LOGGER.warning(return_none_warning)
if not has_yield and not has_return and has_return_none:
_LOGGER.warning(
"Process method returned None (element won't be emitted): %s. Check if intended.",
fn.__self__.__class__)
print(has_yield, has_return, has_return_none)

return False
except Exception as e:
Expand Down
14 changes: 1 addition & 13 deletions sdks/python/apache_beam/transforms/core_test.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@
from apache_beam.typehints import row_type
from apache_beam.typehints import typehints

RETURN_NONE_PARTIAL_WARNING = "No iterator is returned"
RETURN_NONE_PARTIAL_WARNING = "Process method returned None"


class TestDoFn1(beam.DoFn):
Expand Down Expand Up @@ -114,12 +114,6 @@ def process(self, element):
return None


class TestDoFn11(beam.DoFn):
"""test process returning None (no return and no yield)"""
def process(self, element):
pass


class TestDoFn12(beam.DoFn):
"""test process returning None (return statement without a value)"""
def process(self, element):
Expand Down Expand Up @@ -191,12 +185,6 @@ def test_dofn_with_explicit_return_none(self):
assert RETURN_NONE_PARTIAL_WARNING in self._caplog.text
assert str(TestDoFn10) in self._caplog.text

def test_dofn_with_implicit_return_none_missing_return_and_yield(self):
with self._caplog.at_level(logging.WARNING):
beam.ParDo(TestDoFn11())
assert RETURN_NONE_PARTIAL_WARNING in self._caplog.text
assert str(TestDoFn11) in self._caplog.text

def test_dofn_with_implicit_return_none_return_without_value(self):
with self._caplog.at_level(logging.WARNING):
beam.ParDo(TestDoFn12())
Expand Down
Loading