Rust尝试将外部crate导入到不在根目录中的模块时出现“unresolved import”。

huangapple
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英文:

Rust `unresolved import` when trying to import an external crate into a module not in the root directory

问题

I'm very new to Rust, so maybe this is an obvious question, but I couldn't find anything that answered it. I can't seem to import the external crate diesel_derive_enum in my module sub-module database/models.rs. It works perfectly if I simply move the models.rs file to the src/ directory. I'm guessing I'm missing something where I need to tell it to look up to the root level for the external crate?

I have a project that's structured like:

  1. src
  2. ├── database
  3. │   ├── models.rs
  4. │   ├── mod.rs
  5. │   └── schema.rs
  6. └── main.rs

Models.rs

  1. use diesel::pg::PgConnection;
  2. use diesel::prelude::*;
  3. use diesel_derive_enum;
  4. use uuid::Uuid;
  6. use super::schema::market_trade_goods;
  8. #[derive(Debug, PartialEq, Clone, diesel_derive_enum::DbEnum)] // <- error is here
  9. #[ExistingTypePath = "crate::schema::sql_types::SupplyType"]
  10. pub enum SupplyType {
  11.     Scarce,
  12.     Limited,
  13.     Moderate,
  14.     Abundant,
  15. }
  16. // ...then more

database/mod.rs

  1. pub mod models;
  2. pub mod schema;

main.rs

  1. mod database;
  3. use diesel::pg::PgConnection;
  4. use diesel::prelude::*;
  5. use dotenvy::dotenv;
  6. use std::env;
  7. use uuid::Uuid;
  9. use crate::database::models::{SupplyType, TradeGood};
  10. // ...then some more functions and whatnot

I've tried a bunch of different ways of importing things like crate::diesel_derive_enum or extern crate diesel_derive_enum (in models.rs and main.rs). Nothing seems to make a difference, but I'm sure I'm just missing something obvious.

Edit: Full error message is:

  1. error[E0433]: failed to resolve: unresolved import
  2.  --> src/database/models.rs:8:35
  3.   |
  4. 8 | #[derive(Debug, PartialEq, Clone, diesel_derive_enum::DbEnum)]
  5.   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
  6.   |                                   |
  7.   |                                   unresolved import
  8.   |                                   help: a similar path exists: `crate::database::schema`
  9.   |
  10.   = note: this error originates in the derive macro `diesel_derive_enum::DbEnum` (in Nightly builds, run with -Z macro-backtrace for more info)
英文:

I'm very new to Rust, so maybe this is an obvious question, but I couldn't find anything that answered it. I can't seem to import the external crate diesel_derive_enum in my module sub-module database/models.rs. It works perfectly if I simply move the models.rs file to the src/ directory. I'm guessing I'm missing something where I need to tell it to look up to the root level for the external crate?

I have a project that's structured like:

  1. src
  2. ├── database
  3. │   ├── models.rs
  4. │   ├── mod.rs
  5. │   └── schema.rs
  6. └── main.rs

Models.rs

  1. use diesel::pg::PgConnection;
  2. use diesel::prelude::*;
  3. use diesel_derive_enum;
  4. use uuid::Uuid;
  6. use super::schema::market_trade_goods;
  8. #[derive(Debug, PartialEq, Clone, diesel_derive_enum::DbEnum)] // <- error is here
  9. #[ExistingTypePath = "crate::schema::sql_types::SupplyType"]
  10. pub enum SupplyType {
  11.     Scarce,
  12.     Limited,
  13.     Moderate,
  14.     Abundant,
  15. }
  16. // ...then more

database/mod.rs

  1. pub mod models;
  2. pub mod schema;

main.rs

  1. mod database;
  3. use diesel::pg::PgConnection;
  4. use diesel::prelude::*;
  5. use dotenvy::dotenv;
  6. use std::env;
  7. use uuid::Uuid;
  9. use crate::database::models::{SupplyType, TradeGood};
  10. // ...then some more functions and whatnot

I've tried a bunch of different ways of importing things like crate::diesel_derive_enum or extern crate diesel_derive_enum (in models.rs and main.rs). Nothing seems to make a difference, but I'm sure I'm just missing something obvious.

Edit: Full error message is:

  1. error[E0433]: failed to resolve: unresolved import
  2.  --> src/database/models.rs:8:35
  3.   |
  4. 8 | #[derive(Debug, PartialEq, Clone, diesel_derive_enum::DbEnum)]
  5.   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
  6.   |                                   |
  7.   |                                   unresolved import
  8.   |                                   help: a similar path exists: `crate::database::schema`
  9.   |
  10.   = note: this error originates in the derive macro `diesel_derive_enum::DbEnum` (in Nightly builds, run with -Z macro-backtrace for more info)

答案1

得分: 0

  1. #[derive(Debug, PartialEq, Clone, diesel_derive_enum::DbEnum)] // <- error is here
  2. #[ExistingTypePath = "crate::database::schema::sql_types::SupplyType"]
  3. pub enum SupplyType {
  4.     Scarce,
  5.     Limited,
  6.     Moderate,
  7.     Abundant,
  8. }
英文:

The derive macro itself is resolved correctly, but its expansion includes crate::schema::sql_types::SupplyType. The problem is, schema is not directly under the crate root - it is under database. So change it to:

  1. #[derive(Debug, PartialEq, Clone, diesel_derive_enum::DbEnum)] // <- error is here
  2. #[ExistingTypePath = "crate::database::schema::sql_types::SupplyType"]
  3. pub enum SupplyType {
  4.     Scarce,
  5.     Limited,
  6.     Moderate,
  7.     Abundant,
  8. }

huangapple
  • 本文由 发表于 2023年5月11日 05:39:27
  • 转载请务必保留本文链接：https://go.coder-hub.com/76222721.html
  • derive
  • enums
  • rust
  • rust-diesel
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