Fix allOf multi-ref to preserve inheritance with property overrides by koxudaxi · Pull Request #2838 · koxudaxi/datamodel-code-generator

koxudaxi · 2025-12-28T15:11:45Z

Summary by CodeRabbit

Bug Fixes
- Improved JSON schema parser handling of multiple references in schema definitions to properly manage property overrides and prevent inheritance conflicts.
Tests
- Added test coverage for multiple inheritance scenarios with property overrides to validate correct parsing behavior.

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coderabbitai · 2025-12-28T15:11:58Z

📝 Walkthrough

Walkthrough

This change fixes a regression in allOf handling where multiple $ref entries with property overrides lose their class hierarchy. The parser's merge logic is adjusted to properly preserve multi-inheritance when merging conflicting properties from referenced definitions.

Changes

Cohort / File(s)	Summary
Core Parser Logic `src/datamodel_code_generator/parser/jsonschema.py`	Modified `_merge_all_of_object` method to change conflict detection strategy: now only considers conflicts among referenced properties (from multiple $ref entries), excluding child obj.properties from conflict aggregation. Updated docstring clarifies that multiple refs with conflicting property definitions should be merged to avoid MRO issues.
Test Fixtures `tests/data/expected/main/jsonschema/all_of_multi_ref_with_property_override.py`	New Pydantic model definitions demonstrating multi-inheritance: `Person` inherits from both `Thing` and `Location`, with property overrides/extensions (type, name with optional union types and defaults, age).
Test Coverage `tests/main/jsonschema/test_main_jsonschema.py`	Added `test_main_all_of_multi_ref_with_property_override()` test function verifying multi-ref inheritance with property overrides generates correct class hierarchy.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Suggested labels

breaking-change-analyzed

Poem

🐰 A ref that split in two did mend,
Inheritance restored, conflict's end,
Where Person Now inherits true,
From Thing and Location too,
Hierarchy fixed, the schema's friend!

Pre-merge checks and finishing touches

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: fixing allOf multi-ref inheritance preservation with property overrides.
Linked Issues check	✅ Passed	The PR addresses issue #2645 by modifying _merge_all_of_object logic to preserve class hierarchy for allOf with multiple $refs while allowing property overrides.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing allOf multi-ref inheritance: parser logic modification, test data generation, and test case addition.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing touches

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Commit unit tests in branch fix/allof-multi-ref-inheritance

📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 2cc9cee and dd92ba7.

⛔ Files ignored due to path filters (1)

tests/data/jsonschema/all_of_multi_ref_with_property_override.json is excluded by !tests/data/**/*.json and included by none

📒 Files selected for processing (3)

src/datamodel_code_generator/parser/jsonschema.py
tests/data/expected/main/jsonschema/all_of_multi_ref_with_property_override.py
tests/main/jsonschema/test_main_jsonschema.py

🧰 Additional context used

🧬 Code graph analysis (2)

tests/data/expected/main/jsonschema/all_of_multi_ref_with_property_override.py (1)

src/datamodel_code_generator/model/base.py (1)

name (826-828)

tests/main/jsonschema/test_main_jsonschema.py (3)

tests/test_main_kr.py (1)

output_file (44-46)

tests/main/conftest.py (2)

output_file (98-100)

run_main_and_assert (244-408)

src/datamodel_code_generator/__init__.py (1)

chdir (245-255)

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GitHub Check: 3.10 on Windows
GitHub Check: 3.10 on macOS
GitHub Check: benchmarks
GitHub Check: 3.11 on Windows
GitHub Check: 3.12 on macOS
GitHub Check: 3.11 on macOS
GitHub Check: 3.12 on Windows
GitHub Check: 3.13 on Windows
GitHub Check: 3.14 on Windows
GitHub Check: Analyze (python)

🔇 Additional comments (3)

tests/data/expected/main/jsonschema/all_of_multi_ref_with_property_override.py (1)

10-22: Expected multi-inheritance model matches regression scenario

The generated Thing, Location, and Person(Thing, Location) models (with local overrides for type/name and added age) align with the described allOf multi‑ref + property override behavior and follow the existing style of other JSON Schema golden files. No changes needed.

tests/main/jsonschema/test_main_jsonschema.py (1)

1267-1276: New allOf multi‑ref regression test is consistent and well‑wired

This test mirrors the existing single‑ref override test, correctly using chdir(JSON_SCHEMA_DATA_PATH) and pointing to the new JSON schema and expected output file. It should reliably guard the restored multi‑inheritance + override behavior.
src/datamodel_code_generator/parser/jsonschema.py (1)
1738-1771: LGTM! Documentation accurately describes the inheritance preservation fix.

The updated docstring clearly documents the critical behavior that fixes the regression:

Line 1746-1747's early return for single $ref cases preserves inheritance with property overrides

Multi-ref conflict detection (lines 1749-1759) correctly handles MRO scenarios

The clarification that obj.properties are excluded from conflict detection is accurate

The fix correctly allows schemas like:
{
  "allOf": [
    {"$ref": "#/$defs/Thing"},
    {"properties": {"name": {"default": "override"}}}
  ]
}
to generate Person(Thing) with property overrides, restoring pre-v0.38.0 behavior.

Minor note: The phrase "Child property overrides (obj.properties)" on line 1743 is accurate but might be clearer as "Direct properties (obj.properties)" to distinguish them from inline allOf property definitions.

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github-actions · 2025-12-28T15:12:57Z

📚 Docs Preview: https://pr-2838.datamodel-code-generator.pages.dev

codspeed-hq · 2025-12-28T15:14:48Z

CodSpeed Performance Report

Merging #2838 will degrade performance by 17.2%

_{Comparing fix/allof-multi-ref-inheritance (dd92ba7) with main (2cc9cee)}

⚠️

Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

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

Summary

❌ 11 regressions
⏩ 98 skipped¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	WallTime	`test_perf_aws_style_openapi_pydantic_v2`	1.7 s	2 s	-15.12%
❌	WallTime	`test_perf_duplicate_names`	865.8 ms	1,020.5 ms	-15.15%
❌	WallTime	`test_perf_kubernetes_style_pydantic_v2`	2.3 s	2.7 s	-16.25%
❌	WallTime	`test_perf_complex_refs`	1.8 s	2.1 s	-16.22%
❌	WallTime	`test_perf_all_options_enabled`	5.8 s	6.7 s	-13.31%
❌	WallTime	`test_perf_large_models_pydantic_v2`	3.1 s	3.8 s	-17.2%
❌	WallTime	`test_perf_deep_nested`	5.3 s	6.3 s	-14.67%
❌	WallTime	`test_perf_graphql_style_pydantic_v2`	720 ms	842.5 ms	-14.53%
❌	WallTime	`test_perf_openapi_large`	2.5 s	3 s	-15.95%
❌	WallTime	`test_perf_stripe_style_pydantic_v2`	1.8 s	2.1 s	-14.63%
❌	WallTime	`test_perf_multiple_files_input`	3.2 s	3.8 s	-15.37%

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 · 2025-12-28T15:15:45Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.51%. Comparing base (e4394af) to head (dd92ba7).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2838      +/-   ##
==========================================
- Coverage   99.52%   99.51%   -0.01%     
==========================================
  Files          90       90              
  Lines       14092    14245     +153     
  Branches     1674     1695      +21     
==========================================
+ Hits        14025    14176     +151     
- Misses         36       37       +1     
- Partials       31       32       +1

Flag	Coverage Δ
unittests	`99.51% <100.00%> (-0.01%)`	⬇️

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github-actions · 2025-12-28T15:52:40Z

Breaking Change Analysis

Result: Breaking changes detected

Reasoning: This PR modifies the _merge_all_of_object method to no longer include the child schema's properties (obj.properties) when detecting property conflicts between allOf refs. Previously, when a schema had multiple $ref items in allOf AND defined its own properties that overrode parent properties, the code would detect these as "conflicts" and merge all schemas into a single flat class. After this fix, only actual conflicts between the referenced parent schemas trigger merging. This means schemas that were previously flattened will now generate proper multiple inheritance hierarchies. This is a code generation change - users with such schemas will see different generated output.

Content for Release Notes

Code Generation Changes

allOf multi-ref with property overrides now preserves inheritance - Schemas using allOf with multiple $ref items where the child schema also defines properties that override parent properties will now generate classes with multiple inheritance (e.g., class Person(Thing, Location)) instead of a flattened single class with all properties merged inline. Previously, child property overrides were incorrectly treated as conflicts, triggering schema merging. Users relying on the flattened output may need to adjust their code. (Fix allOf multi-ref to preserve inheritance with property overrides #2838)

Before:
```
class Person(BaseModel):
    type: str | None = 'playground:Person'
    name: constr(min_length=1) | None = None
    address: constr(min_length=5)
    age: int | None = None
```
After:
```
class Thing(BaseModel):
    type: str
    name: constr(min_length=1)

class Location(BaseModel):
    address: constr(min_length=5)

class Person(Thing, Location):
    type: str | None = 'playground:Person'
    name: constr(min_length=1) | None = None
    age: int | None = None
```

This analysis was performed by Claude Code Action

github-actions · 2026-01-01T00:05:24Z

🎉 Released in 0.51.0

This PR is now available in the latest release. See the release notes for details.

Fix allOf multi-ref to preserve inheritance with property overrides

dd92ba7

koxudaxi mentioned this pull request Dec 28, 2025

Version >= 0.38 breaks allof class hierarchy #2645

Closed

koxudaxi merged commit bb0eb62 into main Dec 28, 2025
36 of 38 checks passed

koxudaxi deleted the fix/allof-multi-ref-inheritance branch December 28, 2025 15:49

github-actions Bot added breaking-change-analyzed breaking-change labels Dec 28, 2025

coderabbitai Bot mentioned this pull request Dec 30, 2025

feat: add --allof-class-hierarchy option #2869

Merged

coderabbitai Bot mentioned this pull request Jan 12, 2026

Fix allOf array property merging to preserve child $ref #2962

Merged

This was referenced Feb 13, 2026

$ref doesn't work with extra fields #2990

Closed

Merged result in parse_item not passed back to parse_object_fields #2995

Closed

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Fix allOf multi-ref to preserve inheritance with property overrides#2838

Fix allOf multi-ref to preserve inheritance with property overrides#2838
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Merging #2838 will degrade performance by 17.2%

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