I have dependency X in my project that depends on Z and dependency Y that also depends on Z but version requirements are different for X and Y. Also I use Z itself in my project and want it to be the latest version possible. So is there any way to resolve this conflict? e.g. specify that both versions must be downloaded by cargo or override the version that X or Y request
Unless the dependency in question is something super essential (such as an async runtime) AND there is no breaking change between your version and the older version you are good to go. Cargo does all the heavy lifting for you.
Basically cargo downloads both versions one to compile your crate and the other to compile the other crate.
In case of a runtime a mentioned above, code would still compile fine but you would get a runtime error so still code works compiles just fine and everything would work just fine if the code wouldnt try to access something thats not there any more.
This had happened before with tokio ecosystem. Some packages were updated to tokio 1x and some were still on 0x. Again this is an exception, cargo does all the management for you and most of the time you dont really need to worry about it.
This can be caused by a local cache issue. Try deleting the ~/.cargo/registry directory and try to build to project again.
Related
For example, I use barcoders crate:
barcoders = {version = "0.10.0", features = ["image",]}
Is it possible to specify which version of image this dependency should use?
Something like
barcoders = {version = "0.10.0", features = ["image=0.22.3",]}
Because it uses image crate version 0.18.0 and in my project I use latest 0.22.3.
Does it mean that there's only 2 ways to resolve that:
I downgrade version in my package
Barcoders dependency get updated
No, there is no way to specify the version for a dependency's (optional) dependency. This makes sense, as your dependency run their tests only against the version they specify in their Cargo.toml. In this case, as it appears everything you're doing uses open source, you could fork barcoders, update the dependency, run the test suite and if it passes, use your fork. It would also be polite to open an issue in that case.
If barcoders wasn't open-source, so you couldn't fork it, your best bet would be to switch to the version of image that barcoders uses. If your crate is a library, it may be annoying to expose a public interface that uses outdated libraries, but that's life. The "proper" solution to this problem is to wait until image has a 1.0 release, which is basically a forward compatibility promise, then barcoders can specify image = "^1" (i.e. >=1.0.0 <2.0.0). I mention this "solution" only because you appear to have commit privileges on barcoders, in fact you solved your own problem by updating the image dependency in barcoders.
As one of the comments points out, this version compatibility issue is less fragile that it at first seems. So long as types from different versions of some dependency crate don't cross api boundaries, your project can include any number of versions of that dependency simultaneously. Working with multiple versions of libraries took some work from the rust team on name mangling, which you can read about here
No, you can't, and shouldn't, and shouldn't worry.
Libraries were developed at a single point in time, used dependencies with a certain API. The dependency is likely to change some of that between major versions (changing the type a function returns, exposing different patterns, or whatever). This may make it unable to compile anymore. To really update something, you might need to change parts of the code that is using the dependency in the first place.
This is open source world, so you can do so and publish a pull request in the original crate to update. It might be appreciated, but don't underestimate the care that needs to be taken to not break other people's crates yourself when doing so.
Or make your own fork of the crate that updates it just for you.
But you are probably just worried seeing duplicates of the same crate with different versions during compilation. Cargo indeed compiles with different versions, so all calls to the dependended crate will receive what the developer expected when he/she wrote it. This is not a problem, in performance, or amount of instructions that end up in the binary. Just stop worrying.
I want to install a package and all its dependencies as they were at a specific date and time in the past.
I need to use a slightly older version of rustc-nightly, and therefore I need to make sure that all dependencies pulled by cargo install compile against that old version of the compiler.
Currently, when I specify the version of the top-level package to install, it still seems to pull the latest version of some dependencies, which don't build with the old compiler.
No, this is not possible.
Your best options are:
Upgrade the compiler. If you "can't" do this, evaluate why you can't and decide how much benefit you are getting from that.
Add the dependencies to your own Cargo.toml pinned to an older version that does work.
You can try forking the crate index and rolling it back, but there's no guarantee that will work either.
seems to pull the latest version of some dependencies
Yes, most libraries specify dependencies with a semver-compatible range, such as my-library = "1.0". This will allow any version from 1.0.0 to 1.x.y.
Unfortunately, there's no consensus on whether requiring a new version of Rust constitutes a semver-breaking change yet.
See also:
What exactly is considered a breaking change to a library crate?
How to generate Cargo.lock based on last month's crates.io?
I am relatively new to haskell, stack, ghc, etc.
Have been trying a few projects with ghcjs and haven't been able to build any of them, including reflex-dom-stack-demo. I am getting the following error:
In the dependencies for semigroupoids-5.0.0.4:
tagged-0.8.1 from stack configuration does not match >=0.8.5 && <1 (latest matching version is 0.8.5)
needed due to ghcjs-0.2.0 -> semigroupoids-5.0.0.4
Now I cannot understand whether I misconfigured something or there is truly a broken dependency. Deleted ~/.stack multiple times throughout my experiments.
I found this bug in stackage but am unsure whether this is what affects me, and whether it would be fixed once the fix moves through.
Using Ubuntu 17.10..
Any insight is welcome.
The recomended way to create a development environnement for reflex-dom is to use try-reflex.
It is tricky to build reflex-dom with stack, because some needed changes have not yet been added to the upstream libraries.
If you really want to build a reflex-dom environnement with stack, please consider these hints:
Do not use a GHC compiler with a version higher than 8.0.2
Do not use the reflex /reflex-dom versions from Hackage, they are outdated.
Use versions of reflex / reflex-dom from Github.
This repo contains a stack.yaml file, that used to work.
You may also try the stack.yaml file from the answer to this SO question.
I'm working with this module Algorithms.Geometry.LineSegmentIntersection.BentleyOttman using the function "intersections" that returns something of type Intersections which in turn is an alias for Map (Point 2 r) (Associated p r). So, I try to manipulate that result with the corresponding functions of the Data.Map.Lazy module, but I get the following error:
Any ideas on how to fix it? Thanks!
You have two versions of the containers package installed, and have ended up referencing both of them. A Map produced by containers 0.5.7.1 can't be passed to a Map-consuming function from containers 0.5.10.1 (or any mismatched versions), even if their definition of Map in source code is the same.
Without knowing more about your installation history, it's impossible to say exactly why that happened. I would guess you're just using cabal install to install packages as you need them, into the default user-wide package environment? That almost inevitably results in problems like this, eventually.
The easiest immediate solution is to delete your entire store of installed packages and then reinstall everything you need again (preferably all at the same time, not with multiple separate invocations of cabal install).
To prevent this from happening again, to could change your work practices to use tools like cabal sandbox or stack, which facilitate having separate package environments for each project.
Tough to know for sure without more details, but I will assume you are using stack and the latest LTS snapshot (8.6 as of the time I'm writing this).
This could be happening because LTS 8.6 has containers-0.5.7.1, and you are attempting to use a function that is in a newer version (containers-0.5.10.1) which hasn't made its way from Hackage to Stackage yet.
To resolve this, modify your stack.yaml file to include:
extra-deps:
- containers-0.5.10.1
When I was programming my project I introduced various libraries by moving them to my /libs folder and telling Gradle to compile them. Now I've noticed that even if I remove the lines for their compilation from Grade, the project still compiles and works fine.
Why? What was the point of adding them into my Gradle dependencies if I don't need them?
There could be a few cases I can think of:
Some of the dependencies you introduced later on were in turn dependent on the ones you removed. Gradle would download all the dependent libraries and so your project might be working fine.
There could be runtime dependencies on those libraries. So, removing them doesn't affect the compilation but, it might fail if someone invokes a code which depends on the library and you might see a NoClassDefFoundError
Your project used to depend on those libraries earlier but now it doesn't, so removing them doesn't cause any harm.
You added those libraries without actually checking if they were needed
Frankly speaking, all I can do is make some random guesses.