[yaml] : fix create different type elements issue #37585

derrickaw · 2026-02-12T20:20:17Z

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gemini-code-assist · 2026-02-12T20:20:34Z

Summary of Changes

Hello @derrickaw, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the Create transform within Apache Beam's YAML capabilities to gracefully handle inputs comprising a blend of primitive values and dictionary objects. The primary goal is to ensure robust and consistent schema inference by normalizing these mixed types into a uniform dictionary format, thereby preventing potential runtime errors or unexpected schema definitions. This change improves the flexibility and reliability of defining data pipelines using YAML.

Highlights

Mixed Type Handling in Create Transform: The Create transform in Beam YAML now correctly handles inputs that contain a mix of primitive types and dictionaries. Previously, such mixed inputs could lead to inconsistent schema inference.
Schema Normalization: Implemented logic within the create function to normalize mixed input elements. Primitive elements are now wrapped into dictionaries with an 'element' key, ensuring all elements are dictionaries for consistent schema inference.
New Test Cases: Added a new YAML pipeline test case and a corresponding Python unit test to validate the correct behavior of the Create transform with mixed type inputs.

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Changelog

sdks/python/apache_beam/yaml/tests/create.yaml
- Added a new pipeline test case demonstrating the Create transform with mixed type elements (primitives and dictionaries) and asserting the expected output schema.
sdks/python/apache_beam/yaml/yaml_provider.py
- Modified the create function to detect and normalize mixed input types (dictionaries and non-dictionaries) by wrapping primitive elements into dictionaries with an 'element' key.
- Ensured that this normalization only occurs when a mix of types is present, preserving existing behavior for homogeneous inputs.
sdks/python/apache_beam/yaml/yaml_provider_unit_test.py
- Introduced a new unit test class YamlProvidersCreateTest.
- Added test_create_mixed_types to verify the Create transform's ability to process mixed primitive and dictionary inputs correctly, asserting the resulting Row structure.

Activity

The pull request was opened by derrickaw to address issue [Bug]: Beam YAML 'Create' transform crashes on mixed primitive and dictionary elements due to schema inconsistency #37577.
The changes include modifications to the YAML provider logic and the addition of new test cases to validate the fix.

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derrickaw · 2026-02-12T21:47:44Z

Run Python PreCommit 3.13

derrickaw · 2026-02-12T22:23:42Z

/gemini review

gemini-code-assist

Code Review

This pull request fixes an issue with creating elements of different types in YAML by normalizing them before schema inference. The changes are logical and well-tested. I've included one suggestion to improve the efficiency of the type-checking logic, which could be beneficial for large datasets.

sdks/python/apache_beam/yaml/yaml_provider.py

derrickaw · 2026-02-13T01:00:42Z

Run Python_Runners PreCommit 3.11

github-actions · 2026-02-13T01:39:34Z

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tvalentyn · 2026-02-13T02:07:36Z

sdks/python/apache_beam/yaml/yaml_provider_unit_test.py

+class YamlProvidersCreateTest(unittest.TestCase):
+  def test_create_mixed_types(self):
+    with beam.Pipeline(options=beam.options.pipeline_options.PipelineOptions(
+        pickle_library='cloudpickle')) as p:


pickle_library should be already cloudpickle by default

removed, thanks

tvalentyn · 2026-02-13T02:10:16Z

sdks/python/apache_beam/yaml/yaml_provider.py

      raise TypeError('elements must be a list of elements')

+    if elements:
+      # Normalize elements to be all dicts or all primitives.


should some of this comment content be part of the docstring?

(lmk if you plan changes here, otherwise I will merge)

just updated, thanks

tvalentyn · 2026-02-13T02:12:03Z

i thought whether we should mention this in changes.md. looking at the issue, this is not a breaking change, correct?

derrickaw · 2026-02-13T02:41:53Z

i thought whether we should mention this in changes.md. looking at the issue, this is not a breaking change, correct?

It shouldn't be, as an error should be thrown with existing code.

derrickaw added 3 commits February 12, 2026 15:37

fix mixed types

62b120a

add another create pipeline

7e73ef0

remove comment

0be36e6

github-actions bot added python yaml labels Feb 12, 2026

derrickaw changed the title ~~20260212 check yaml create provider~~ [yaml] : fix create different type elements issue Feb 12, 2026

gemini-code-assist bot reviewed Feb 12, 2026

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sdks/python/apache_beam/yaml/yaml_provider.py Outdated Show resolved Hide resolved

address gemini comment about performance

2fc9dd7

derrickaw marked this pull request as ready for review February 13, 2026 01:27

github-actions bot added the Next Action: Reviewers label Feb 13, 2026

tvalentyn reviewed Feb 13, 2026

View reviewed changes

tvalentyn approved these changes Feb 13, 2026

View reviewed changes

address doc string and cloud pickle comments

0cbdff4

[yaml] : fix create different type elements issue #37585

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[yaml] : fix create different type elements issue #37585

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derrickaw commented Feb 12, 2026

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