Fix relative URL refs with path-only root ids by koxudaxi · Pull Request #3085 · koxudaxi/datamodel-code-generator

koxudaxi · 2026-04-14T06:48:43Z

Summary

resolve relative $id values against the retrieval URL before using them as the base for relative $ref resolution
add resolver coverage for relative root $id plus base_url
add a CLI regression test for --url input with path-only $id and relative external $ref

Root Cause

When a schema was fetched via --url and declared a path-only root $id like /schemas/v1/main.schema.json, that $id replaced the retrieval URL as the reference base without first being normalized to an absolute URL. The next relative $ref was therefore resolved as a local filesystem path instead of remaining remote.

Validation

tox -e type
tox -e readme
tox -e cli-docs -- --check
tox -e config-types -- --check
tox -e py314-parallel -- tests/test_reference.py tests/main/jsonschema/test_main_jsonschema.py -k 'relative_root_id or root_id_differs_from_base_url or url_with_relative_root_id_resolves_relative_refs or root_id_jsonschema_with_remote_file or remote_ref'
tox -e py312-parallel -- tests/test_reference.py tests/main/jsonschema/test_main_jsonschema.py -k 'relative_root_id or root_id_differs_from_base_url or url_with_relative_root_id_resolves_relative_refs or root_id_jsonschema_with_remote_file or remote_ref'

Fixes: #3080

Summary by CodeRabbit

Bug Fixes

Fixed URL resolution logic for relative JSON Schema $ref references when using remote schemas with relative root $id paths. Relative references now correctly resolve against the provided base URL.

Tests

Added end-to-end and unit tests to verify correct resolution of relative references in schemas with relative root identifiers.

coderabbitai · 2026-04-14T06:48:49Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: 5fd68a75-144d-4236-a08f-b5f988952369

📥 Commits

Reviewing files that changed from the base of the PR and between f0960e9 and d8d928d.

📒 Files selected for processing (3)

src/datamodel_code_generator/reference.py
tests/main/jsonschema/test_main_jsonschema.py
tests/test_reference.py

📝 Walkthrough

Walkthrough

Modified ModelResolver.resolve_ref method to fix relative $ref resolution when using the --url option. The logic now correctly uses base_url as the effective base when set, incorporating root_id appropriately via join_url, rather than treating root_id as a fallback. Added unit and E2E tests validating the fix.

Changes

Cohort / File(s)	Summary
Reference Resolution Logic `src/datamodel_code_generator/reference.py`	Updated `ModelResolver.resolve_ref` to prioritize `base_url` when determining the effective base URL. When `root_id` is present and not a full URL, it is joined with `base_url` via `join_url` instead of being used as a fallback. Added `PLR0915` noqa directive to method signature.
Unit Test `tests/test_reference.py`	Added test `test_resolve_ref_with_relative_root_id_and_base_url` to validate that relative `$ref` resolves correctly against an HTTP `base_url` when `root_id` is path-only.
E2E Test `tests/main/jsonschema/test_main_jsonschema.py`	Added test `test_main_url_with_relative_root_id_resolves_relative_refs` to verify CLI behavior with `--url` option. Mocks HTTP requests and confirms relative references are fetched from the correct derived URL and generated output is correct.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A URL so grand, a path so small,
The ref once lost, now answers the call,
Base and root join hands so bright,
External schemas resolved just right! 🌐✨

🚥 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 clearly summarizes the main change: fixing relative URL refs when root ids are path-only, which directly addresses the core bug described in issue `#3080`.
Linked Issues check	✅ Passed	The PR fully addresses issue `#3080`: it fixes relative $ref resolution when schemas have path-only root $id values by normalizing them against the retrieval URL, preventing incorrect filesystem path resolution.
Out of Scope Changes check	✅ Passed	All changes directly support the linked issue fix: core logic updates to ModelResolver.resolve_ref, a unit test for the resolver behavior, and an E2E CLI test validating the --url scenario with relative root $id.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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Create PR with unit tests
Commit unit tests in branch fix-relative-url-ref-3080

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github-actions · 2026-04-14T06:49:26Z

📚 Docs Preview: https://pr-3085.datamodel-code-generator.pages.dev

codspeed-hq · 2026-04-14T06:51:28Z

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 fix-relative-url-ref-3080 (d8d928d) with main (f0960e9)}

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 · 2026-04-14T07:00:16Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (f0960e9) to head (d8d928d).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #3085   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           87        87           
  Lines        18274     18300   +26     
  Branches      2089      2090    +1     
=========================================
+ Hits         18274     18300   +26

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

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Raekkeri · 2026-04-15T09:11:33Z

Hi @koxudaxi

Thanks for the quick response! This works on my machine.

B.R. the author of #3080

github-actions · 2026-04-15T15:50:45Z

Breaking Change Analysis

Result: No breaking changes detected

Reasoning: This PR is a bug fix for URL resolution when fetching schemas via --url with a path-only root $id. It corrects incorrect behavior (relative $id was being treated as a filesystem path instead of being normalized against the retrieval URL). No CLI options, Python API, default behavior, or generated code output formats are changed. The fix only affects previously-broken cases, making them work correctly, so existing correct usage is unaffected.

This analysis was performed by Claude Code Action

github-actions · 2026-04-16T17:12:47Z

🎉 Released in 0.56.1

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

Fix relative URL refs with path-only root ids

dd04c13

koxudaxi mentioned this pull request Apr 14, 2026

[codex] Fix relative URL refs with path-only root ids #3084

Closed

koxudaxi marked this pull request as ready for review April 14, 2026 06:55

Merge branch 'main' into fix-relative-url-ref-3080

d8d928d

Raekkeri approved these changes Apr 15, 2026

View reviewed changes

koxudaxi merged commit d7a1f71 into main Apr 15, 2026
38 checks passed

koxudaxi deleted the fix-relative-url-ref-3080 branch April 15, 2026 15:50

github-actions Bot added the breaking-change-analyzed label Apr 15, 2026

github-actions Bot mentioned this pull request Apr 16, 2026

Relative $ref does not resolve externally when using --url option #3080

Closed

coderabbitai Bot mentioned this pull request Apr 24, 2026

Support for local redirection for json schema $ref with http[s]:// uris #3103

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Fix relative URL refs with path-only root ids#3085

Fix relative URL refs with path-only root ids#3085
koxudaxi merged 2 commits intomainfrom
fix-relative-url-ref-3080

koxudaxi commented Apr 14, 2026 •

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Summary

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koxudaxi commented Apr 14, 2026 •

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