Unable to compile due to reimport of tokio

[SiddheshKanawade]

I am having a reimport of tokio in my repository and hence unable to compile the project. I am not sure how should I resolve it.

Working repository: https://github.com/casbin-rs/examples

I figured out that I was having a version difference of tokio in actix-casbin and actix-casbin-auth. As a temporary resolve I updated the version to 1.19 and used a local patch to check before pushing it to main repository. Still I am getting the following error and not sure how to resolve this.

The Cargo.toml looks like:

1. actix-middleware-example

[dependencies]
http = "0.2.1"
actix =  "0.13.0"
actix-rt = "2.7.0"
actix-web = "4.1.0"
actix-service = "2.0.2"
actix-cors = "0.6.1"
futures = "0.3.5"
failure = "0.1.8"
serde = "1.0.116"
serde_derive = "1.0.116"
serde_json = "1.0.57"
derive_more = "0.99.10"
chrono = { version = "0.4.18", features = ["serde"] }
diesel = { version = "1.4.5", features = ["postgres","r2d2", "chrono"] }
diesel_migrations = "1.4.0"
dotenv = "0.15.0"
env_logger = "0.9.0"
log = "0.4.11"
jsonwebtoken = "8.1.0"
bcrypt = "0.13.0"
csv = "1.1.3"
walkdir = "2.3.1"
diesel-adapter = { version = "0.9.0", default-features = false, features = ["postgres","runtime-async-std"] }
uuid = {version = "1.1.2", features = ["v4"] }

[patch.crates-io]
actix-casbin= {path = "/home/siddhesh/Desktop/Siddhesh/Casbin/casbin-rs_Actix/actix-casbin", default-features = false, features = [ "runtime-async-std" ]}
actix-casbin-auth = {path = "/home/siddhesh/Desktop/Siddhesh/Casbin/actix-casbin-auth/actix-casbin-auth", default-features = false, features = [ "runtime-async-std" ]}

2. actix-fileadapter-rbac

[dependencies]
actix-web = "4.1.0"
actix-rt = "2.7.0"
casbin = "2.0.9"
dotenv = "0.15"
loge = {version = "0.4", default-features = false, features = ["colored", "chrono"]}

3. actix-pgsql-simple

[dependencies]
casbin = "2.0.9"
diesel-adapter = { version = "0.9.0", features = ["postgres"] }
async-std = { version = "1.6", features = ["attributes"] }

diesel = { version = "1.4", features = ["postgres", "serde_json", "r2d2"] }

actix-web = { version = "4.1.0" }
actix-rt = "2.7.0"
serde = "1.0"
serde_derive = "1.0"

dotenv = "0.15"
env_logger = "0.9"
futures = "0.3"
log = "0.4"

4. ntex-fileadapter-acl

[dependencies]
ntex = { version = "0.5", features = ["tokio"] }
casbin = "2.0.9"
dotenv = "0.15"
loge = {version = "0.4.2", default-features = false, features = ["colored", "chrono"]}

The exact error I am getting is:

error[E0252]: the name `IoError` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:20:10
   |
13 |     io::{BufReader, Error as IoError, ErrorKind},
   |                     ---------------- previous import of the type `IoError` here
...
20 |     io::{Error as IoError, ErrorKind},
   |          ^^^^^^^^^^^^^^^^--
   |          |
   |          `IoError` reimported here
   |          help: remove unnecessary import
   |
   = note: `IoError` must be defined only once in the type namespace of this module

error[E0252]: the name `ErrorKind` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:20:28
   |
13 |     io::{BufReader, Error as IoError, ErrorKind},
   |                                       --------- previous import of the type `ErrorKind` here
...
20 |     io::{Error as IoError, ErrorKind},
   |                            ^^^^^^^^^ `ErrorKind` reimported here
   |
   = note: `ErrorKind` must be defined only once in the type namespace of this module

error[E0252]: the name `Path` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:21:5
   |
14 |     path::Path,
   |     ---------- previous import of the type `Path` here
...
21 |     path::Path,
   |     ^^^^^^^^^^ `Path` reimported here
   |
   = note: `Path` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
21 |     path::Path as OtherPath,
   |     ~~~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `File` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:25:5
   |
11 |     fs::File,
   |     -------- previous import of the type `File` here
...
25 |     fs::File,
   |     ^^^^^^^^ `File` reimported here
   |
   = note: `File` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
25 |     fs::File as OtherFile,
   |     ~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `BufReader` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:26:42
   |
13 |     io::{BufReader, Error as IoError, ErrorKind},
   |          --------- previous import of the type `BufReader` here
...
26 |     io::{AsyncBufReadExt, AsyncWriteExt, BufReader},
   |                                          ^^^^^^^^^ `BufReader` reimported here
   |
   = note: `BufReader` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
26 |     io::{AsyncBufReadExt, AsyncWriteExt, BufReader as OtherBufReader},
   |                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `Cursor` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/config.rs:13:11
   |
6  |     io::{BufReader, Cursor, Error as IoError, ErrorKind},
   |                     ------ previous import of the type `Cursor` here
...
13 | use std::{io::Cursor, path::Path};
   |           ^^^^^^^^^^ `Cursor` reimported here
   |
   = note: `Cursor` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
13 | use std::{io::Cursor as OtherCursor, path::Path};
   |           ~~~~~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `Path` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/config.rs:13:23
   |
10 | use async_std::{fs::File, path::Path};
   |                           ---------- previous import of the type `Path` here
...
13 | use std::{io::Cursor, path::Path};
   |                       ^^^^^^^^^^ `Path` reimported here
   |
   = note: `Path` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
13 | use std::{io::Cursor, path::Path as OtherPath};
   |                       ~~~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `BufReader` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/config.rs:16:36
   |
6  |     io::{BufReader, Cursor, Error as IoError, ErrorKind},
   |          --------- previous import of the type `BufReader` here
...
16 |     AsyncBufReadExt, AsyncReadExt, BufReader, Error as IoError, ErrorKind,
   |                                    ^^^^^^^^^ `BufReader` reimported here
   |
   = note: `BufReader` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
16 |     AsyncBufReadExt, AsyncReadExt, BufReader as OtherBufReader, Error as IoError, ErrorKind,
   |                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `IoError` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/config.rs:16:47
   |
6  |     io::{BufReader, Cursor, Error as IoError, ErrorKind},
   |                             ---------------- previous import of the type `IoError` here
...
16 |     AsyncBufReadExt, AsyncReadExt, BufReader, Error as IoError, ErrorKind,
   |                                               ^^^^^^^^^^^^^^^^--
   |                                               |
   |                                               `IoError` reimported here
   |                                               help: remove unnecessary import
   |
   = note: `IoError` must be defined only once in the type namespace of this module

error[E0252]: the name `ErrorKind` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/config.rs:16:65
   |
6  |     io::{BufReader, Cursor, Error as IoError, ErrorKind},
   |                                               --------- previous import of the type `ErrorKind` here
...
16 |     AsyncBufReadExt, AsyncReadExt, BufReader, Error as IoError, ErrorKind,
   |                                                                 ^^^^^^^^^-
   |                                                                 |
   |                                                                 `ErrorKind` reimported here
   |                                                                 help: remove unnecessary import
   |
   = note: `ErrorKind` must be defined only once in the type namespace of this module

error[E0252]: the name `File` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/config.rs:20:5
   |
10 | use async_std::{fs::File, path::Path};
   |                 -------- previous import of the type `File` here
...
20 | use tokio::fs::File;
   |     ^^^^^^^^^^^^^^^ `File` reimported here
   |
   = note: `File` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
20 | use tokio::fs::File as OtherFile;
   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

error[E0252]: the name `Path` is defined multiple times
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/model/default_model.rs:20:5
   |
17 | use async_std::path::Path;
   |     --------------------- previous import of the type `Path` here
...
20 | use std::path::Path;
   |     ^^^^^^^^^^^^^^^ `Path` reimported here
   |
   = note: `Path` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
20 | use std::path::Path as OtherPath;
   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

error[E0599]: no method named `next_line` found for struct `async_std::io::Lines` in the current scope
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:66:38
   |
66 |         while let Some(line) = lines.next_line().await? {
   |                                      ^^^^^^^^^ method not found in `async_std::io::Lines<async_std::io::BufReader<async_std::fs::File>>`

error[E0599]: no method named `next_line` found for struct `async_std::io::Lines` in the current scope
  --> /home/siddhesh/.cargo/registry/src/github.com-1ecc6299db9ec823/casbin-2.0.9/src/adapter/file_adapter.rs:91:38
   |
91 |         while let Some(line) = lines.next_line().await? {
   |                                      ^^^^^^^^^ method not found in `async_std::io::Lines<async_std::io::BufReader<async_std::fs::File>>`

Some errors have detailed explanations: E0252, E0599.
For more information about an error, try `rustc --explain E0252`.
error: could not compile `casbin` due to 14 previous errors

[Darksonn]

It sounds like you've tried to enable both the Tokio and async-std feature of casbin. You can't do that.

[SiddheshKanawade]

I tried disabling the default features of casbin to avoid the use of runtime-tokio, but it didn't worked. Also, I figured out that on removing actix-middleware-example from the main cargo.toml, the repository compiles successfully. So might be actix-middleware-example is making problem but I am not sure how to correct it.
I tried using:

casbin = { version = "2.0.9", default-features = false, features = ["runtime-async-std", "logging", "incremental"] }

instead of

casbin = "2.0.9"

But it failed.
Casbin depends on following features:

default = ["runtime-tokio", "incremental"]
amortized = ["ritelinked/ahash-amortized", "ritelinked/inline-more-amortized"]
cached = ["lru"]
explain = []
glob = ["globset"]
incremental = []
ip = ["ip_network"]
logging = ["slog", "slog-term", "slog-async"]
runtime-async-std = ["async-std"]
runtime-tokio = ["tokio/fs", "tokio/io-util"]
watcher = []
async-std (optional)
globset (optional)
ip_network (optional)
lru (optional)
slog (optional)
slog-async (optional)
slog-term (optional)
tokio (optional)
tokio-stream (optional)

Any idea on how should I resolve the issue?

[Darksonn]

Actix uses Tokio. If you use actix-web, then you must use Tokio and not async-std.