# Contributor handoff — diesel-rs/diesel

> Canonical page: https://codevetter.com/unpack/diesel/agent-handoff

# Contributor handoff — diesel-rs/diesel

Scanned commit 5cdf54e1434b87084a4630c100249f1028f3e32d (2026-10-02). Generated by codevetter codevetter 1.15.0 on 2026-10-02.

Source inspection; upstream code and tests were not executed.

Use the pinned manifests and affected crate implementation as the starting context, because the supplied inventory contains simplified version and backend information. Tests and CI were inspected, not executed, and this brief covers a bounded set of source paths. Future implementation work should preserve backend gates and use dedicated test databases before authorizing execution. Public API changes, generated diagnostics, schema snapshots, and embedded migration rebuilds require special attention.
- Read Cargo.toml and the affected crate manifest first: Rust 1.88.0/edition 2024, Diesel 2.3.13, four backend features, and target-specific SQLite dependencies are concrete constraints in this revision. — [Cargo.toml#L40-L43](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/Cargo.toml#L40-L43) [diesel/Cargo.toml#L1-L13](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/Cargo.toml#L1-L13) [diesel/Cargo.toml#L54-L58](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/Cargo.toml#L54-L58) [diesel/Cargo.toml#L89-L110](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/Cargo.toml#L89-L110)
- For query-runtime changes, follow RunQueryDsl::load, LoadQuery::internal_load, backend LoadConnection, statement preparation, and row decoding before choosing an edit boundary. — [diesel/src/query_dsl/mod.rs#L1702-L1706](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/src/query_dsl/mod.rs#L1702-L1706) [diesel/src/query_dsl/load_dsl.rs#L62-L71](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/src/query_dsl/load_dsl.rs#L62-L71) [diesel/src/pg/connection/mod.rs#L255-L289](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/src/pg/connection/mod.rs#L255-L289) [diesel/src/query_dsl/load_dsl.rs#L128-L148](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel/src/query_dsl/load_dsl.rs#L128-L148)
- For CLI/schema work, read cli.rs, main.rs, config.rs, and print_schema.rs together; configuration overrides, relative paths, multi-schema context, patches, and locked-file handling all affect observable output. — [diesel_cli/src/cli.rs#L20-L44](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_cli/src/cli.rs#L20-L44) [diesel_cli/src/config.rs#L29-L58](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_cli/src/config.rs#L29-L58) [diesel_cli/src/print_schema.rs#L330-L359](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_cli/src/print_schema.rs#L330-L359) [diesel_cli/src/main.rs#L294-L325](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_cli/src/main.rs#L294-L325)
- The inspected test sources and workflow declarations describe intended checks, not execution results: review CLI schema snapshots/compilation, migration assertions, compile-failure diagnostics, and CI configuration before planning validation. — [diesel_cli/tests/print_schema.rs#L717-L749](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_cli/tests/print_schema.rs#L717-L749) [diesel_cli/tests/migration_run.rs#L7-L32](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_cli/tests/migration_run.rs#L7-L32) [diesel_compile_tests/tests/trybuild.rs#L96-L102](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_compile_tests/tests/trybuild.rs#L96-L102) [.github/workflows/ci.yml#L352-L375](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/.github/workflows/ci.yml#L352-L375)
- In authorized implementation work, start with the affected backend/test and use cargo xtask run-tests for broader checks; xtask resolves backend-specific database variables, runs migrations first, and invokes nextest with coordinated crate features. — [CONTRIBUTING.md#L124-L128](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/CONTRIBUTING.md#L124-L128) [xtask/src/tests/mod.rs#L186-L220](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/xtask/src/tests/mod.rs#L186-L220) [xtask/src/tests/mod.rs#L224-L256](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/xtask/src/tests/mod.rs#L224-L256)
- Preserve compile-error and snapshot expectations deliberately: BLESS presence rewrites ui_test outputs, while CONTRIBUTING.md calls for reviewing insta changes; tidy and semver-checks are existing tooling entrypoints. — [diesel_compile_tests/tests/trybuild.rs#L96-L102](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_compile_tests/tests/trybuild.rs#L96-L102) [CONTRIBUTING.md#L194-L208](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/CONTRIBUTING.md#L194-L208) [xtask/src/main.rs#L19-L30](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/xtask/src/main.rs#L19-L30)
- Embedded migrations have a documented rebuild trap: changes only to migration files may not rerun the procedural macro, and consuming applications should use build.rs rerun-if-changed declarations. — [diesel_migrations/migrations_macros/src/lib.rs#L105-L120](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/diesel_migrations/migrations_macros/src/lib.rs#L105-L120)
- Contribution conventions require minimal, reviewed, verified changes and AI-use disclosure; the guide reserves mentoring/good-first-issue work from AI use and asks authors to write their own PR descriptions. — [CONTRIBUTING.md#L155-L171](https://github.com/diesel-rs/diesel/blob/5cdf54e1434b87084a4630c100249f1028f3e32d/CONTRIBUTING.md#L155-L171)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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