Skip default_factory wrapping for non-callable type aliases by butvinm · Pull Request #3012 · koxudaxi/datamodel-code-generator

butvinm · 2026-03-02T00:47:00Z

Summary by CodeRabbit

Bug Fixes
- Prevented unnecessary wrapping of root-model default values when the root reference is a type alias.
Tests
- Added tests covering enum-literal type alias defaults with combined configuration flags to ensure defaults are not wrapped.

…udaxi#3009) When --use-type-alias + --use-annotated + --enum-field-as-literal all are combined, the generator produced `default_factory=lambda: Mode('default')` where Mode is a PEP 695 type alias (not callable). Add a TypeAliasBase guard in __wrap_root_model_default_values to skip wrapping for type aliases. Co-Authored-By: Claude Opus 4.6 <[email protected]>

coderabbitai · 2026-03-02T00:47:18Z

No actionable comments were generated in the recent review. 🎉

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Reviewing files that changed from the base of the PR and between 3371925 and 6e6d034.

📒 Files selected for processing (2)

src/datamodel_code_generator/parser/base.py
tests/main/jsonschema/test_main_jsonschema.py

🚧 Files skipped from review as they are similar to previous changes (1)

src/datamodel_code_generator/parser/base.py

📝 Walkthrough

Walkthrough

Refines the guard that wraps root-model default values: wrapping now occurs only when data_type.reference.source is the root data model type and that source is not a TypeAliasBase, preventing defaults from being wrapped when the root reference is a type alias. No other control flow changes.

Changes

Cohort / File(s)	Summary
Core Logic Guard `src/datamodel_code_generator/parser/base.py`	Tightened the condition that wraps root-model default values by excluding cases where the root reference source is a `TypeAliasBase`, preventing generation of callables for type-alias defaults.
Generated Expected Output `tests/data/expected/main/jsonschema/enum_literal_type_alias_default.py`	Added expected output showing a `Mode = Literal['default','plan']` type alias and a `Model` with `mode: Mode
Test Case `tests/main/jsonschema/test_main_jsonschema.py`	Added test `test_main_jsonschema_enum_literal_type_alias_default` (appears twice in this diff) to verify combined flags `--use-type-alias`, `--use-annotated`, `--enum-field-as-literal all` produce unwrapped defaults for type-alias roots targeting Python 3.12 / pydantic_v2.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

Fix array RootModel default value handling in parser #2963: Related changes around root-type default handling and type-alias root propagation.
fix: wrap RootModel primitive defaults with default_factory #2714: Modifies RootModel default wrapping and introduces WrappedDefault behavior.
fix: quote forward references in recursive RootModel generic parameters #2720: Adjusts parser conditions for RootModel vs TypeAliasBase handling.

Suggested labels

breaking-change-analyzed

Poem

🐰 I hopped through parser lines with glee,
I nudged the guard so defaults stay free.
No calling aliases — a kinder fate,
Strings remain simple, tidy, and straight. ✨

🚥 Pre-merge checks | ✅ 5

✅ 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 directly describes the main code change: narrowing the wrapping condition to skip default_factory wrapping for non-callable type aliases, which is the core fix for the linked issue.
Linked Issues check	✅ Passed	The PR fixes issue `#3009` by preventing default_factory wrapping for type aliases, which eliminates the invalid callable invocation of TypeAliasType in the generated code.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing the type alias default wrapping issue: the parser logic fix, the expected output test file, and the new test case all address the bug described in `#3009`.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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codspeed-hq · 2026-03-02T00:49:53Z

Merging this PR will not alter performance

⚠️

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.

✅ 11 untouched benchmarks
⏩ 98 skipped benchmarks¹

_{Comparing butvinm:fix/type-alias-default-factory-3009 (dca857f) with main (c36ac6c)}

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. ↩

coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/datamodel_code_generator/parser/base.py`:
- Line 2161: The long conditional needs to be reformatted to satisfy
ruff-format: break the if condition into a parenthesized multi-line expression
and align each clause on its own line so the expression is wrapped and
PEP8-friendly (target the if in parser/base.py that references
data_type.reference, data_type.reference.source, self.data_model_root_type, and
TypeAliasBase); update the if at the start of the conditional to use parentheses
and line breaks for each isinstance check and the negation, then run the
project's formatter (ruff/black) to commit the formatted change so CI passes.

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📥 Commits

Reviewing files that changed from the base of the PR and between 9955314 and 3371925.

⛔ Files ignored due to path filters (1)

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

📒 Files selected for processing (3)

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

Skip the enum_literal_type_alias_default test on black < 23 since PEP 695 `type` statement syntax is unsupported. Reformat long conditional in parser/base.py to satisfy ruff line-length. Co-Authored-By: Claude Opus 4.6 <[email protected]>

codecov · 2026-03-02T01:02:37Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (c36ac6c) to head (dca857f).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #3012   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           94        94           
  Lines        18130     18133    +3     
  Branches      2099      2099           
=========================================
+ Hits         18130     18133    +3

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

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Co-Authored-By: Claude Opus 4.6 <[email protected]>

butvinm · 2026-03-02T08:45:02Z

I am not sure how my code might cause performance regression. According to CodSpeed report, the regression seems to be coming from black formatting

github-actions · 2026-03-03T08:33:27Z

Breaking Change Analysis

Result: No breaking changes detected

Reasoning: This PR is a bug fix, not a breaking change. The previous behavior generated invalid Python code (wrapping type alias defaults in default_factory with a lambda that tries to call the type alias, which is not callable). The fix produces correct code. Breaking changes involve changing behavior that previously worked correctly - this PR corrects behavior that was always broken, making it a pure bug fix.

This analysis was performed by Claude Code Action

github-actions · 2026-03-04T04:17:15Z

🎉 Released in 0.54.1

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

butvinm marked this pull request as draft March 2, 2026 00:48

coderabbitai Bot reviewed Mar 2, 2026

View reviewed changes

Comment thread src/datamodel_code_generator/parser/base.py Outdated

test: simplify docstring for type alias default test

6e6d034

Co-Authored-By: Claude Opus 4.6 <[email protected]>

butvinm marked this pull request as ready for review March 2, 2026 01:46

Merge branch 'main' into fix/type-alias-default-factory-3009

dca857f

koxudaxi merged commit 69eda18 into koxudaxi:main Mar 3, 2026
39 checks passed

github-actions Bot added the breaking-change-analyzed label Mar 3, 2026

github-actions Bot mentioned this pull request Mar 4, 2026

--use-type-alias + --use-annotated + --enum-field-as-literal all generates callable TypeAliasType in default_factory #3009

Closed

This was referenced Mar 8, 2026

--use-type-alias emits raw dict defaults for $ref object unions #3034

Closed

--use-type-alias: inline object unions validate defaults through the first branch only #3035

Closed

fix #3034 and #3035 by introducing ValidatedDefault #3040

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Skip default_factory wrapping for non-callable type aliases#3012

Skip default_factory wrapping for non-callable type aliases#3012
koxudaxi merged 4 commits intokoxudaxi:mainfrom
butvinm:fix/type-alias-default-factory-3009

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