Add new lint to enforce snake-case usage with new api_dto macro #247

nanoandrew4 · 2026-01-15T10:13:19Z

Partially addresses #225

Other lints were considered but rejected for now in favor of enforcing the guidelines, especially around documentation, with macros at compile time.

Summary by CodeRabbit

New Features
- Added api_dto macro to generate REST DTO serialization, schema and request/response wiring.
- New lints: enforce snake_case for API JSON names; forbid api_dto in contract layer; require api_dto for API DTOs.
Improvements
- Converted many REST DTOs and tests to macro-driven DTOs for consistent serialization and OpenAPI output.
- Operation builders and APIs now require DTO marker traits for stricter request/response typing.
Documentation
- Expanded docs and READMEs for the new macro and lint guidance.

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coderabbitai · 2026-01-15T10:13:31Z

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🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding a new lint to enforce snake-case usage with the new api_dto macro.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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Signed-off-by: nanoandrew4 <andressmithdev@pm.me>

coderabbitai

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/Cargo.toml`:
- Around line 21-84: Add the missing example entry for the UI test file by
creating an example target named "fail_pascal_case" that points to
"ui/fail_pascal_case.rs" so every file in the ui/ directory has a corresponding
[[example]] entry; update the Cargo.toml examples list to include this new
[[example]] with name fail_pascal_case and path ui/fail_pascal_case.rs.

🧹 Nitpick comments (3)

dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/README.md (1)
1-9: Well-documented lint rule.

The README clearly explains what the lint does, why it matters, and provides helpful examples.

Minor markdown nit: Consider using ## (h2) instead of ### (h3) for section headings to follow proper heading hierarchy after the h1 title.
📝 Optional heading level fix
 # de0803_api_snake_case

-### What it does
+## What it does
 Checks that DTOs (structs and enums) defined in the `api/rest` directory use `snake_case` for serde renaming configurations. Specifically:
 1. `#[serde(rename_all = "...")]` on structs/enums must be "snake_case".
 2. `#[serde(rename = "...")]` on fields must be in snake_case.

-### Why is this bad?
+## Why is this bad?
 The API standard requires all JSON properties to be in `snake_case`. Using other casing styles (like `camelCase`, `PascalCase`, etc.) leads to inconsistent API responses and violations of the project's API guidelines.

-### Example
+## Example
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/Cargo.toml (1)
1-19: Good crate structure following conventions.

The crate correctly uses workspace dependencies for clippy_utils, dylint_linting, lint_utils, dylint_testing, and serde as per coding guidelines.

Consider updating edition to "2024" for consistency.

Other lint crates in this PR (e.g., de0110_no_schema_for_on_gts_structs, de0902_no_schema_for_on_gts_structs) use edition = "2024". This crate uses edition = "2021", which creates inconsistency across the workspace.
Suggested fix
 [package]
 name = "de0803_api_snake_case"
 version = "0.1.0"
 authors = ["Hypernetix"]
 description = "DTOs must not use CamelCase or PascalCase in serde rename_all, only snake_case is allowed"
-edition = "2021"
+edition = "2024"
 publish = false
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_pascal_case.rs (1)
5-6: Minor: Comment description doesn't match the violation type.

The comment says "DTO fields must not use non-snake_case" but this test validates a type-level rename_all attribute, not a field-level rename. Consider updating to:
-// Should trigger DE0803 - DTO fields must not use non-snake_case in serde rename/rename_all
+// Should trigger DE0803 - DTOs must not use non-snake_case in serde rename_all
This would more accurately describe the specific violation being tested and align with the actual lint message.

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📥 Commits

Reviewing files that changed from the base of the PR and between 2478dc5 and 84540b5.

⛔ Files ignored due to path filters (1)

dylint_lints/Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (45)

dylint_lints/Cargo.toml
dylint_lints/de01_contract_layer/de0101_no_serde_in_contract/Cargo.toml
dylint_lints/de01_contract_layer/de0110_no_schema_for_on_gts_structs/Cargo.toml
dylint_lints/de02_api_layer/de0203_dtos_must_have_serde_derives/Cargo.toml
dylint_lints/de02_api_layer/de0204_dtos_must_have_toschema_derive/Cargo.toml
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/Cargo.toml
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/README.md
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/rust-toolchain
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/src/lib.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_camel_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_camel_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_camel_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_camel_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_kebab_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_kebab_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_pascal_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_pascal_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_screaming_kebab_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_screaming_kebab_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_screaming_snake_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_screaming_snake_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_uppercase.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_field_uppercase.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_kebab_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_kebab_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_lowercase.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_lowercase.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_pascal_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_pascal_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_screaming_kebab_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_screaming_kebab_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_screaming_snake_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_screaming_snake_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_uppercase.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/fail_uppercase.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass_field_lowercase.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass_field_lowercase.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass_field_snake_case.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass_field_snake_case.stderr
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass_outside_api.rs
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/ui/pass_outside_api.stderr
dylint_lints/de09_gts_layer/de0901_gts_string_pattern/Cargo.toml
dylint_lints/de09_gts_layer/de0902_no_schema_for_on_gts_structs/Cargo.toml

🧰 Additional context used

📓 Path-based instructions (2)

dylint_lints/**/Cargo.toml

📄 CodeRabbit inference engine (dylint_lints/AGENTS.md)

dylint_lints/**/Cargo.toml: In Cargo.toml for lint crates, reference common workspace dependencies (clippy_utils, dylint_linting, lint_utils) using .workspace = true to avoid duplication
Define example targets in lint crate Cargo.toml with [[example]] sections for each UI test case
Register new lint crates by adding them to the members list in the workspace root Cargo.toml

Files:

dylint_lints/de01_contract_layer/de0101_no_serde_in_contract/Cargo.toml
dylint_lints/de09_gts_layer/de0901_gts_string_pattern/Cargo.toml
dylint_lints/de02_api_layer/de0203_dtos_must_have_serde_derives/Cargo.toml
dylint_lints/de01_contract_layer/de0110_no_schema_for_on_gts_structs/Cargo.toml
dylint_lints/de09_gts_layer/de0902_no_schema_for_on_gts_structs/Cargo.toml
dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/Cargo.toml
dylint_lints/Cargo.toml
dylint_lints/de02_api_layer/de0204_dtos_must_have_toschema_derive/Cargo.toml

dylint_lints/**/src/lib.rs

📄 CodeRabbit inference engine (dylint_lints/AGENTS.md)

dylint_lints/**/src/lib.rs: Use declare_pre_expansion_lint! for lints that check derive attributes before macro expansion (e.g., detecting serde/utoipa derives)
Use EarlyLintPass with rustc_ast for pre-expansion lints that need to see #[derive(...)] attributes directly before macro expansion
Use declare_early_lint! for checking syntax and structure after macro expansion but before type resolution without type information
Use declare_late_lint! with LateLintPass and rustc_hir when type information or semantic analysis is required
Use ui_test_examples when tests need external dependencies (serde, utoipa) or have logically distinct scenarios with explicit test organization
Use ui_test when all tests have no external dependencies and you have many small, similar test cases for simpler configuration
Every lint crate MUST include a test_comment_annotations_match_stderr test using lint_utils::test_comment_annotations_match_stderr to validate comment/stderr alignment
Use is_in_contract_module_ast() helper from lint_utils crate to check if an AST item is in a contract/ directory
Document lint behavior in doc comments within the lint implementation
Select pre-expansion lint pass for detecting serde/utoipa derives that must be checked before proc macros expand

Files:

dylint_lints/de08_rest_api_conventions/de0803_api_snake_case/src/lib.rs

🧠 Learnings (22)