default value fixes

[jbellenger]

Hi there! I'm the maintainer of graphql-conformance, a GraphQL verifier similar to thesis-graphql-go.

I noticed that graphql-go has a couple of deviations from the spec and I thought I might be able to contribute a fix for one of the easy ones (see graphql-go's conformance page for other gaps).

This PR fixes an issue that prevents arguments with non-nullable types from having default values.

For example, in this configuration:

# schema
type Query { x(y:Int! = 0): Int }

# query
{ x }

graphql-go returns this error:

  {
    "data": null,
    "errors": [
      {
        "message": "Field \"x\" argument \"y\" of type \"Int!\" is required but not provided.",
        "locations": [
          {
            "line": 1,
            "column": 3
          }
        ]
      }
    ]
  }

With this PR applied, the above query now returns:

  {
    "data": {
      "x": 0
    }
  }

This kind of usage is explicitly allowed by section 5.4.3 of the graphql-spec:

An argument is required if the argument type is non-null and does not have a default value. Otherwise, the argument is optional

Thank you for considering this PR! I'm not familiar with this code-base or its conventions, so please feel free to point out any issue no matter how small.

Summary by CodeRabbit

• Bug Fixes

  • Improved GraphQL argument validation to correctly recognize that non-null arguments with default values should not be required when omitted. This prevents false validation errors for properly defined schema arguments.

• Tests

  • Added test coverage for both field arguments and directive arguments with default values to ensure validation behaves correctly in all scenarios.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 31da9cfa-ca05-483b-905b-e500f8240a10

📥 Commits

Reviewing files that changed from the base of the PR and between d5f8f3c and 17cfd19.

📒 Files selected for processing (2)

• rules.go
• rules_provided_non_null_arguments_test.go

---

📝 Walkthrough

Walkthrough

The ProvidedNonNullArgumentsRule has been refined to only treat non-null arguments as "required" when they lack a default value. The validation logic now checks that both the argument type is non-null AND no default value exists, preventing false errors for non-null arguments satisfied via schema-level defaults.

Changes

Cohort / File(s)	Summary
Rule Implementation rules.go	Updated ProvidedNonNullArgumentsRule field-argument and directive-argument validation to add DefaultValue == nil condition, allowing non-null arguments with schema defaults to be optional.
Test Coverage rules_provided_non_null_arguments_test.go	Added two new test cases validating that the rule passes when non-null arguments have schema-level defaults—one for field arguments and one for directive arguments.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A rule refined with care so fine,
Non-null arguments need not whine,
When defaults bloom like morning dew,
The schema's promise sees them through,
No errors now for arguments blessed,
With defaults making validation rest! ✨

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Title check	❓ Inconclusive	The title 'default value fixes' is vague and doesn't clearly convey the specific change being made to the ProvidedNonNullArgumentsRule for handling non-null arguments with defaults.	Consider a more descriptive title such as 'Allow non-null arguments with default values' or 'Fix ProvidedNonNullArgumentsRule to handle default values' to better communicate the primary change.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
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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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coveralls]

coverage: 92.284%. remained the same — jbellenger:nonnull-args-default-value into graphql-go:master