Fix Avro required defaults

[koxudaxi]

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[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 4131e7a and d74b53b.

📒 Files selected for processing (24)

• src/datamodel_code_generator/__init__.py
• src/datamodel_code_generator/parser/asyncapi.py
• src/datamodel_code_generator/parser/avro.py
• tests/data/expected/main/asyncapi/multi_format_schemas.py
• tests/data/expected/main/avro/py310/constructs.py
• tests/data/expected/main/avro/py310/official_long_list.py
• tests/data/expected/main/avro/py310/official_schema_pass/record_fields_with_defaults.py
• tests/data/expected/main/avro/py310/spec_matrix.py
• tests/data/expected/main/avro/py311/constructs.py
• tests/data/expected/main/avro/py311/official_long_list.py
• tests/data/expected/main/avro/py311/official_schema_pass/record_fields_with_defaults.py
• tests/data/expected/main/avro/py311/spec_matrix.py
• tests/data/expected/main/avro/py312/constructs.py
• tests/data/expected/main/avro/py312/official_long_list.py
• tests/data/expected/main/avro/py312/official_schema_pass/record_fields_with_defaults.py
• tests/data/expected/main/avro/py312/spec_matrix.py
• tests/data/expected/main/avro/py313/constructs.py
• tests/data/expected/main/avro/py313/official_long_list.py
• tests/data/expected/main/avro/py313/official_schema_pass/record_fields_with_defaults.py
• tests/data/expected/main/avro/py313/spec_matrix.py
• tests/data/expected/main/avro/py314/constructs.py
• tests/data/expected/main/avro/py314/official_long_list.py
• tests/data/expected/main/avro/py314/official_schema_pass/record_fields_with_defaults.py
• tests/data/expected/main/avro/py314/spec_matrix.py

💤 Files with no reviewable changes (1)

• src/datamodel_code_generator/parser/avro.py

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📝 Walkthrough

Walkthrough

This PR removes automatic propagation of Avro default values from schemas into generated Pydantic models. The change disables apply_default_values_for_required_fields in the Avro parser, eliminates AsyncAPI-specific handling for Avro defaults, and stops copying field-level defaults during Avro-to-JSON-Schema conversion. Test expectations across Python 3.10–3.14 are updated to reflect generated models without defaults.

Changes

Avro Default Values Removal

Layer / File(s)	Summary
Core Avro default handling removal src/datamodel_code_generator/__init__.py, src/datamodel_code_generator/parser/asyncapi.py, src/datamodel_code_generator/parser/avro.py	Avro parser configuration no longer forces apply_default_values_for_required_fields: True. AsyncAPI's apply_avro_default_values field and _avro_default_values context manager are removed. Avro-to-JSON-Schema conversion stops copying default values for record fields and enums.
Test expected outputs tests/data/expected/main/asyncapi/multi_format_schemas.py, tests/data/expected/main/avro/py3{10,11,12,13,14}/*.py	Expected Pydantic model outputs across AsyncAPI and Avro fixtures are updated to remove default value assignments. Optional fields lose explicit = None defaults; fields with literal defaults (e.g., = 0, = True, = []) are declared without defaults, making them required at model construction.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• koxudaxi/datamodel-code-generator#3242: Previously added the apply_avro_default_values mechanism being removed here; directly coupled to the same AsyncAPI Avro default-handling code path.
• koxudaxi/datamodel-code-generator#3054: Addressed required-field default rendering logic via use_default_with_required and __set_validate_default_on_fields, which interacts with the same default propagation behavior being removed.

Suggested labels

breaking-change, breaking-change-analyzed

Suggested reviewers

• ilovelinux

Poem

🐰 A rabbit hops through schemas bright,
Defaults once set now fade from sight,
Avro fields stand bare and true,
No more magic—just what's due!
✨🥕

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: fixing how Avro required field defaults are handled in code generation.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[github-actions]

📚 Docs Preview: https://pr-3254.datamodel-code-generator.pages.dev

[codspeed-hq]

Merging this PR will improve performance by 18.82%

⚠️ Unknown Walltime execution environment detected

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For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

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⚡ 11 improved benchmarks
⏩ 98 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	test_perf_all_options_enabled	6.4 s	5.2 s	+22.17%
⚡	WallTime	test_perf_deep_nested	5.9 s	4.9 s	+21.49%
⚡	WallTime	test_perf_kubernetes_style_pydantic_v2	2.9 s	2.4 s	+20.37%
⚡	WallTime	test_perf_aws_style_openapi_pydantic_v2	2.1 s	1.8 s	+19.49%
⚡	WallTime	test_perf_openapi_large	3.2 s	2.7 s	+19.01%
⚡	WallTime	test_perf_graphql_style_pydantic_v2	885.9 ms	746.3 ms	+18.7%
⚡	WallTime	test_perf_complex_refs	2.2 s	1.9 s	+18.45%
⚡	WallTime	test_perf_large_models_pydantic_v2	4 s	3.4 s	+17.41%
⚡	WallTime	test_perf_duplicate_names	1,115.7 ms	955.1 ms	+16.81%
⚡	WallTime	test_perf_multiple_files_input	3.8 s	3.3 s	+16.81%
⚡	WallTime	test_perf_stripe_style_pydantic_v2	2.3 s	1.9 s	+16.45%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing fix-avro-required-defaults (d74b53b) with main (4131e7a)}

Footnotes

1. 98 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (4131e7a) to head (d74b53b).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #3254   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          112       112           
  Lines        25209     25194   -15     
  Branches      3185      3182    -3     
=========================================
- Hits         25209     25194   -15     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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