I am using serde-xml-rs crate in our project and I need to modify some code from that crate, so what I did is to generate a patch file, and apply it by calling cargo patch. In my Cargo.toml has stuff like following:
serde-xml-rs = "0.6.0"
[package.metadata.patch.serde-xml-rs]
version = "0.6.0"
patches = [
"patches/0001.patch"
]
[patch.crates-io]
serde-xml-rs = { path = "./target/patch/serde-xml-rs-0.6.0" }
When I called cargo run, project still use original version of serde-xml-rs instead of using values in patch.crates-io tag
But I could see that my patch is applied correctly to the target folder "./target/patch/serde-xml-rs-0.6.0", because if I modify toml file to following, it worked.
{ path = "./target/patch/serde-xml-rs-0.6.0" }
Related
I am a newbie of rust, when I tried to write a rust web api, but the project contains hyphen so I could not use it, if the project name like diesel_demo , I could use it like this:
use diesel_demo::schema::posts::dsl::*;
but if my project name like diesel-demo, what should I do to use it? I can not change my project name now with hyphen reddwarf-music. I read the docs and tell me the cargo will trans the - to _ by default, so I am use it like this:
use reddwarf_music::schema::posts::dsl::*;
but shows error like this:
~/Documents/GitHub/reddwarf-music on develop! ⌚ 17:56:51
$ cargo build ‹ruby-2.7.2›
Compiling hello-rocket v0.1.0 (/Users/dolphin/Documents/GitHub/reddwarf-music)
error[E0433]: failed to resolve: use of undeclared crate or module `reddwarf_music`
--> src/biz/music/music.rs:1:5
|
1 | use reddwarf_music::schema::posts::dsl::*;
| ^^^^^^^^^^^^^^ use of undeclared crate or module `reddwarf_music`
what should I do handle the - in rust? By the way the scheme is generate in my local src, not from third package. This is my project structure:
this is my Cargo.toml:
[package]
name = "reddwarf_music"
version = "0.1.0"
edition = "2018"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
rocket = { version = "0.5.0-rc.1", features = ["json"] }
rand = "0.8.4"
serde = { version = "1.0.64", features = ["derive"] }
serde_json = "1.0.64"
reqwest = "0.11.4"
# database
diesel = { version = "1.4.4", features = ["postgres"] }
dotenv = "0.15.0"
Within a crate you don't use the crates name with use, rather, you refer to the crate itself using the identifier crate.
So inside your crate "reddwarf-music", when you want to use an internal symbol, instead of writing
use reddwarf_music::schema::posts::dsl::*;
you write
use crate::schema::posts::dsl::*;
I have a binary that depends on a library. In the library I specified these features:
[features]
default = []
fet = []
I would expect feature fet would ONLY be activated when it is compiled with the feature flag. In my binary the Cargo.toml looks like this:
[dependencies]
a = { path = "./a" }
[features]
default = []
I haven't specified the fet feature in the Cargo.toml, however this gives me a compilation error in my binary:
fn main() {
if cfg!(feature = "fet") {
compile_error!("not expected");
}
}
Why is feature fet still activated in my binary? I executed these commands and get the same error:
cargo run
cargo run --features=default
Ideally, I want my binary to activate certain features from dependencies if they are explicitly mentioned in the cargo run command (in the --features flag). Is this possible? I was hoping this would work in my binary Cargo.toml:
[features]
default = []
fet = ["a/fet"]
and feature fet would be activated if I ran this command:
cargo run --features=fet
The cfg! macro will be expanded to true or false depending on if the condition is true or false, so if the feature flag is not set, it will still expand to this:
fn main() {
if false {
compile_error!("not expected");
}
}
The compile_error! macro will still be invoked, so you'll get the compiler error either way.
The cfg! macro is mostly useful when you can rely on the compiler optimizing away branches that will never be taken, such as an if false branch. The code still needs to compile before optimization, though, so it's less useful when the code will only compile if the condition is true or false.
What you'd want to use instead is either a #[cfg] attribute or the cfg_if::cfg_if! macro:
// with #[cfg] attribute
fn main() {
#[cfg(feature = "fet")]
compile_error!("not expected");
}
// with cfg_if!
use cfg_if::cfg_if;
fn main() {
cfg_if!{
if #[cfg(feature = "fet")] {
compile_error!("not expected");
}
}
}
I'm trying to make a simple program checking execution times on two different branches of the same rust project.
I wanted to have my .toml look something like this
[dependencies]
cron_original = { git = "https://github.com/zslayton/cron" }
cron_fork = { git = "https://github.com/koenichiwa/cron", branch = "feature/reimplement-queries"}
And my program look something like this:
fn main() {
let expression = String::from("0-59 * 0-23 ?/2 1,2-4 ? *");
let schedule_orig = cron_original::Schedule::from_str(expression);
let schedule_fork = cron_fork::Schedule::from_str(expression);
// Check difference in execution times on these structs
}
but I'm getting no matching package named 'cron_fork' found. Is there anyway to import a package with a specific alias? I was thinking about creating something that would automate checks like this.
You need to specify package keys for those dependencies so cargo knows that you really want those packages even though you specify a different name:
[dependencies]
cron_original = { git = "https://github.com/zslayton/cron", package="cron" }
cron_fork = { git = "https://github.com/koenichiwa/cron", branch = "feature/reimplement-queries", package="cron" }
See the Renaming dependencies in Cargo.toml section in Specifying Dependencies documentation for details.
I'm trying to get a development environment going for Haskell, using Nix. I have a default.nix that just refers to my .cabal file for the list of packages. But one package I want to use, numhask-space, won't build, because the tests are failing. So I'm trying to override it and skip the tests.
Here's my default.nix:
# default.nix
let
pkgs = import <nixpkgs> { };
in
pkgs.haskellPackages.developPackage {
root = ./.;
modifier = drv:
pkgs.haskell.lib.addBuildTools drv (with pkgs.haskellPackages;
[ cabal-install
ghcid
]);
source-overrides = {
numhask-space = pkgs.haskell.lib.dontCheck pkgs.haskellPackages.numhask-space;
};
}
But I must not be doing this right, because I get the error:
cabal2nix: user error (Failed to fetch source. Does this source exist? Source {sourceUrl = "/nix/store/w3pcvlj7b0k44v629k00kw2b0k86fcyj-numhask-space-0.3.0", sourceRevision = "", sourceHash = Guess "", sourceCabalDir = ""})
In short, how can I override this haskell package so that it doesn't run the tests, and I can install it in my development environment?
source-overrides overrides sources of the packages, that is, literally, the src attributes, rather than packages as a whole. You should use the overrides argument instead:
overrides = self: super: {
numhask-space = pkgs.haskell.lib.dontCheck super.numhask-space;
};
I have the following dependencies in my Cargo.toml file:
[package]
name = "api-client-tutorial"
version = "0.1.0"
authors = ["Supercomputing Systems AG <info#scs.ch>"]
edition = "2018"
[dependencies]
substrate-api-client = { git = "https://github.com/scs/substrate-api-client.git" }
codec = { package = "parity-scale-codec", features = ["derive"], version = "1.0.0", default-features = false }
[dependencies.primitives]
git = "https://github.com/paritytech/substrate"
rev = "3bf9540e72df5ecb3955845764dfee7dcdbb26b5"
package = "substrate-primitives"
[dependencies.keyring]
git = "https://github.com/paritytech/substrate"
rev = "3bf9540e72df5ecb3955845764dfee7dcdbb26b5"
package = "substrate-keyring"
I am unsure of the difference between dependencies section and dependencies.primitives section, but the package substrate-primitives is included in the primitives section.
I have seen that substrate_primitives has the module sr25519 I need to use, but when I try to import it in my code:
use substrate_api_client::{Api, node_metadata};
use substrate_primitives::sr25519;
fn main() {
// instantiate an Api that connects to the given address
let url = "127.0.0.1:9944";
// if no signer is set in the whole program, we need to give to Api a specific type instead of an associated type
// as during compilation the type needs to be defined.
let api = Api::<sr25519::Pair>::new(format!("ws://{}", url));
let meta = api.get_metadata();
println!("Metadata:\n {}", node_metadata::pretty_format(&meta).unwrap());
}
I get the following error:
unresolved import `substrate_primitives`
use of undeclared type or module `substrate_primitives`rustc(E0432)
main.rs(2, 5): use of undeclared type or module `substrate_primitives`
How do I import sr25519 so that I can use the following line in my code?
let api = Api::<sr25519::Pair>::new(format!("ws://{}", url));
The difference between tables under [dependencies] and the [dependencies.primitives] table is that the table for the primitives dependency is not inlined. You could also just inline the primitives dependency and put it under [dependencies] like that:
primitives = { git = "https://github.com/paritytech/substrate", rev = "3bf9540e72df5ecb3955845764dfee7dcdbb26b5", package = "substrate-primitives" }
The toml documentation can give you more details on tables and inline tables.
Regarding your problem. You cannot import the crate like that, because it is renamed to primitives. The package field specifies the real name of the dependency and the table name defines the new name which is used to import it inside your project. For details have a look at the cargo documentation.
Your import should therefore look like this: use primitives::sr25519;