Fix patternProperties/propertyNames key constraints lost with field_constraints by koxudaxi · Pull Request #2994 · koxudaxi/datamodel-code-generator

koxudaxi · 2026-02-14T04:58:56Z

Fixes: #2988

Summary by CodeRabbit

Release Notes

New Features
- Pattern constraints on dictionary keys are now consistently applied in all code generation modes, ensuring proper regex validation.
- Generated code properly enforces regex patterns on dictionary keys through constrained string types.
Bug Fixes
- Resolved inconsistent behavior where pattern constraints were not applied to dictionary keys in certain configurations.
Tests
- Added comprehensive test cases for pattern properties with annotated types and field constraints to verify correct constraint application.

…onstraints

coderabbitai · 2026-02-14T04:59:15Z

📝 Walkthrough

Walkthrough

The changes fix a bug where pattern constraints on JSON schema dictionary keys (patternProperties and propertyNames) were not being preserved when using the --use-annotated option. The parser now consistently applies pattern constraints to dictionary key types regardless of field_constraints mode, with corresponding test fixtures demonstrating the corrected output.

Changes

Cohort / File(s)	Summary
Parser Logic `src/datamodel_code_generator/parser/jsonschema.py`	Modified `parse_pattern_properties` and `parse_property_names` to always apply pattern constraints to dict keys when present, removing the `field_constraints` gating condition.
Test Fixtures `tests/data/expected/main/jsonschema/pattern_properties_field_constraints.py`, `tests/data/expected/main/jsonschema/pattern_properties_use_annotated.py`, `tests/data/expected/main/jsonschema/property_names_pattern_field_constraints.py`	New and updated expected output files showing pattern-constrained dict keys using `constr()` or `Annotated` types in Pydantic v2 models.
Test Coverage `tests/main/jsonschema/test_main_jsonschema.py`	Added test `test_jsonschema_pattern_properties_use_annotated` to verify pattern constraints are preserved when using `--use-annotated` with `patternProperties` schema.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

#2770: Both PRs modify parse_pattern_properties to handle merged regex patterns for dict key types in patternProperties.
#2766: Both PRs modify patternProperties handling in the JSON schema parser, with overlapping changes to pattern constraint application logic.
#2824: Both PRs modify parse_property_names in the same file to alter how dictionary key type constraints are derived from propertyNames constraints.

Suggested labels

breaking-change-analyzed, breaking-change

Poem

🐰 Pattern guards now stand so tall,
Keys constrained through it all,
With --use-annotated we rejoice,
Regex patterns have their voice!
Bug squashed bright, the rules apply,
Hopping higher toward the sky! 🎉

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Merge Conflict Detection	⚠️ Warning	❌ Merge conflicts detected (5 files): ⚔️ `src/datamodel_code_generator/model/pydantic/base_model.py` (content) ⚔️ `src/datamodel_code_generator/parser/jsonschema.py` (content) ⚔️ `tests/data/expected/main/jsonschema/pattern_properties_field_constraints.py` (content) ⚔️ `tests/main/jsonschema/test_main_jsonschema.py` (content) ⚔️ `tests/main/test_dynamic_models.py` (content) These conflicts must be resolved before merging into `main`.	Resolve conflicts locally and push changes to this branch.

✅ 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 describes the main change: fixing preservation of patternProperties/propertyNames key constraints when using field_constraints mode.
Linked Issues check	✅ Passed	The code changes directly address issue `#2988` by ensuring pattern constraints are applied to dictionary keys even in field_constraints mode, implementing the fix to preserve key constraints with --use-annotated.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing pattern constraints on dictionary keys in patternProperties/propertyNames; no unrelated modifications are present.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

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🧪 Generate unit tests (beta)

Create PR with unit tests
Post copyable unit tests in a comment
Commit unit tests in branch fix/pattern-properties-field-constraints

⚔️ Resolve merge conflicts (beta)

Auto-commit resolved conflicts to branch fix/pattern-properties-field-constraints
Create stacked PR with resolved conflicts
Post resolved changes as copyable diffs in a comment

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github-actions · 2026-02-14T04:59:47Z

📚 Docs Preview: https://pr-2994.datamodel-code-generator.pages.dev

codecov · 2026-02-14T05:04:25Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (b58970a) to head (d488ad6).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #2994   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           94        94           
  Lines        18051     18065   +14     
  Branches      2091      2090    -1     
=========================================
+ Hits         18051     18065   +14

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

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github-actions · 2026-02-14T05:17:28Z

Breaking Change Analysis

Result: No breaking changes detected

Reasoning: This PR is a bug fix that corrects inconsistent behavior where patternProperties and propertyNames constraints were incorrectly dropped when using --field-constraints or --use-annotated flags. Before the fix, dict[str, Bar] was incorrectly generated; after the fix, dict[constr(regex=...), Bar] is correctly generated. While this changes the generated output, it's a correctness fix rather than a breaking change - the previous behavior was a bug that silently dropped constraints that should have been preserved according to the JSON Schema. Users expecting the buggy behavior would see different output, but the new output correctly reflects what the schema specifies.

This analysis was performed by Claude Code Action

github-actions · 2026-02-14T16:21:44Z

🎉 Released in 0.54.0

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

Fix patternProperties/propertyNames key constraints lost with field_c…

d488ad6

…onstraints

koxudaxi merged commit 0f1bc0f into main Feb 14, 2026
36 of 37 checks passed

koxudaxi deleted the fix/pattern-properties-field-constraints branch February 14, 2026 05:16

github-actions Bot added the breaking-change-analyzed label Feb 14, 2026

github-actions Bot mentioned this pull request Feb 14, 2026

patternProperties key constraints doesn't get preserved with --use-annotated #2988

Closed

coderabbitai Bot mentioned this pull request Mar 2, 2026

Doesn't work to combine --use-annotated and --use-non-positive-negative-number-constrained-types #3014

Closed

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Fix patternProperties/propertyNames key constraints lost with field_constraints#2994

Fix patternProperties/propertyNames key constraints lost with field_constraints#2994
koxudaxi merged 1 commit intomainfrom
fix/pattern-properties-field-constraints

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