I've been trying to update a Create React App to use yarn 2 and plug and play (PNP). When I do use nodeLinker: node-modules in the .yarnrc.yml, I can successfully start the dev-server. Without it, I end up with
./src/App.scss (./.yarn/$$virtual/css-loader-virtual-fe3fa7be11/0/cache/css-loader-npm-3.4.2-300ee159b3-2.zip/node_modules/css-loader/dist/cjs.js??ref--6-oneOf-5-1!./.yarn/cache/postcss-loader-npm-3.0.0-f4ab99b685-2.zip/node_modules/postcss-loader/src??postcss!./.yarn/cache/resolve-url-loader-npm-3.1.1-cf1a268137-2.zip/node_modules/resolve-url-loader??ref--6-oneOf-5-3!./.yarn/unplugged/sass-loader-virtual-14ae4e1150/node_modules/sass-loader/dist/cjs.js??ref--6-oneOf-5-4!./src/App.scss)
Error: A package is trying to access a peer dependency that should be provided by its direct ancestor but isn't
Required package: node-sass (via "node-sass")
Required by: sass-loader#virtual:74ba539c0b6c6c8346ea151c91664bff0bef13782983a6f90ddf1a26160140360771dcf40d0863b46ff7add674bc2c42a37daea25f24f4ea96f7843786460ecd#npm:8.0.2 (via /Users/me/color-contrast-matrix/.yarn/unplugged/sass-loader-virtual-14ae4e1150/node_modules/sass-loader/dist/)
It looks like yarn 2 provides a way of overriding a packages dependencies. You have to provide the missing dependency, at least in this case.
From the docs current link:
Some packages may have been specified incorrectly with regard to their
dependencies - for example with one dependency being missing, causing
Yarn to refuse it the access. The packageExtensions fields offer a way
to extend the existing package definitions with additional
information. If you use it, consider sending a PR upstream and
contributing your extension to the plugin-compat database.
After installing node-sass and adding this config, compilation succeeded.
# .yarnrc.yml
packageExtensions:
'sass-loader#*':
optionalDependencies:
node-sass: '*'
Building on wegry's answer, a better way would be to fix up react-scripts, since that's where the missing peer dependency is.
#.yarnrc.yml
packageExtensions:
'react-scripts#*':
peerDependencies:
node-sass: ^4.0.0 || ^5.0.0' # Or sass: ^1.3.0'
I'm using versions that match the peerDependency of the version of sass-loader that is currently depended on by react-scripts. (I hope by the time the next version of react-scripts comes out, they'll have fixed this bug.)
What this is doing, is telling Yarn that react-scripts really should have peer-depended on sass (and also node-sass for that matter), so that sass-loader can use them.
sass-loader itself has defined its dependencies correctly.
Related
I'm using Yarn#3.0.2 in my project.
I have patched a package (#pkg/pkg) with the command yarn patch #pkg/pkg and I am using it as a devDependency with the patch: protocol.
Now I need to make another patch to the same package - but when I run the same command I get Multiple candidate packages found [...].
It works when trying to target the original package (using yarn patch #pkg/pkg#x.x.x), but I can't seem to find a way to target the patched project.
Any skilled yarn developer out there?
(Possibly useful information: I cannot use the resolutions field for the patch since #pkg/pkg is a CLI which does not seem to work with this approach)
The solution was choose the patch suggested with the error and encapsule it in qoutes such as:
yarn patch "patch:..."
For a few days I have been getting these messages:
*> yarn run v1.21.1 $ react-scripts start
There might be a problem with the project dependency tree. It is
likely not a bug in Create React App, but something you need to fix
locally.
The react-scripts package provided by Create React App requires a
dependency:
"eslint": "^6.6.0"
Don't try to install it manually: your package manager does it
automatically. However, a different version of eslint was detected
higher up in the tree:
/home/sol/Repository/node_modules/eslint (version: 6.3.0)
Manually installing incompatible versions is known to cause
hard-to-debug issues.
If you would prefer to ignore this check, add
SKIP_PREFLIGHT_CHECK=true to an .env file in your project. That will
permanently disable this message but you might encounter other issues.
To fix the dependency tree, try following the steps below in the exact
order:
Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
Delete node_modules in your project folder.
Remove "eslint" from dependencies and/or devDependencies in the package.json file in your project folder.
Run npm install or yarn, depending on the package manager you use.
In most cases, this should be enough to fix the problem. If this has
not helped, there are a few other things you can try:
If you used npm, install yarn (http://yarnpkg.com/) and repeat the above steps with it instead.
This may help because npm has known issues with package hoisting which may get resolved in future versions.
Check if /home/sol/Repository/node_modules/eslint is outside your project directory.
For example, you might have accidentally installed something in your home folder.
Try running npm ls eslint in your project folder.
This will tell you which other package (apart from the expected react-scripts) installed eslint.
If nothing else helps, add SKIP_PREFLIGHT_CHECK=true to an .env file
in your project. That would permanently disable this preflight check
in case you want to proceed anyway.
P.S. We know this message is long but please read the steps above :-)
We hope you find them helpful!
error Command failed with exit code 1. info Visit
https://yarnpkg.com/en/docs/cli/run for documentation about this
command.*
I tried everything above, but nothing helps and I'm really upset about this situation because I can't get my code to work.
Can someone help me with easy instructions because I don't have time anymore to try and find a solution to the problem.
I could not solve the problem:
There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.
The react-scripts package provided by Create React App requires a dependency:
"eslint": "^6.6.0"
Don't try to install it manually: your package manager does it automatically.
However, a different version of eslint was detected higher up in the tree:
/Users/elvestrindade/node_modules/eslint (version: 6.2.2)
I have been using npm for a personal project and just recently stumbled across yarn. Would there be any harm or "intended side effects" to switching to yarn's package manager in the same project where I had been using npm?
Although a few commenters here say its ok to mix both yarn and npm on the same project, after using yarn and npm and then yarn again, this is what yarn has to say about it:
warning package-lock.json found. Your project contains lock files generated by tools
other than Yarn. It is advised not to mix package managers in order to avoid resolution
inconsistencies caused by unsynchronized lock files. To clear this warning, remove
package-lock.json.
Since to me it is not any harm to using both them into one project.
I use npm and yarn (50/50) in dev environment.
But on ci/di i use only yarn because it is faster, and i reduce build minutes thanks yarn.
Also they both create different .lock file names.
Nobody told about the lock files.
Imagine you use yarn on dev environment, and yarn on your build/production servers. When you install a package using yarn, and your project works on your computer, you probably would want to keep it working on a production environment (your server).
That being sad, you would commit you yarn.lock file, that "saves" the exact versions of each package you have, when the project ran on your computer.
On your buid/production server you should call yarn install, but asking to keep all the same versions with --frozen-lockfile parameter. Some even say "yarn install --frozen-lockfile should be the default behavior", and I agree.
Then... another dev jump in the project you are working and install a package using npm (other than yarn). That new package will not be included in your yarn.lock file, but, a new package-json.lock file would be created, telling the exact packages versions it is using.
When that commit arrives on your build/production server, it will crash, fail, because that new package doesn't exist on yarn.lock file. Someone would need to pull that changes, call a yarn to install the dependences and update the lock file with the new package dependences, and push it again to the repo.
A quick point about using the lock file or not. If you call a 'yarn install' on your build/production server some weeks after the last install on your machine, the server would have many other new versions than your last "stable" version. It already happened to me many times.
I published recently the package-locks-checks, which help ensure you have not just one lock file but also locked each package version on your project.
There will be a point that one or both will no longer work and your project will be stuck at only using the existing lock file. Meaning, the issue probably will involve installation fails if you opt to reinstall without a lock file. And that also means failure to create a new lock file, so you are stuck with the existing one that you are trying to get rid off in the first place. We are actually encountering this issue in one of our projects. Because it is so big, no one tries to fix the issue and just rely on the existing lock file.
So, even if we say it's a rare case that it won't cause harm. Mixing npm and yarn should be avoided.
Here https://classic.yarnpkg.com/en/docs/migrating-from-npm/ we may find a confirmation that Yarn's resolution algorithm is compatible with NPM resolution algorithm.
Inside a npm project (with package.json) if you run yarn it will read your node_modules folder (using the resolution algorithm) and create a yarn.lock file with your project's locked dependency tree.
Based on that I assume that they are compatible inside the same project.
Update 30/04/2021
My original reply refers to yarn 1 (classic), although I've just created a React app with create-react-app tool and it creates the project's repository with package.json + yarn.lock by default. Again, another demonstration that it's fine (even with the warning mentioned by Dave Pile).
At the end of the day this is a matter of putting both together to work and checking yourself...
Plus you get a warning from yarn as Dave Pile said because we have to push *-lock.json files changes you have to consider using npm version >= 7 to make sure whenever you install packages by npm it will update your yarn-lock.json file too.
Because whenever you install the packages either by npm or yarn depends on what you have chosen for updating a dependency in the package.json (Using tilde ( ~ ) which gives you bug fix releases and caret ( ^ ) gives you backward-compatible new functionality) it will update you.lock file and since you have to push it might happen that you have different version of lock files.
I am just learning about yarn and npm.
I want to use a particular package that crashes my app. I found a project issue which looks like fix has been implemented and merged with master. A comment says npm package has not been updated yet.
I have added the package to my project:
yarn add react-widgets
I thought I could use yarn to add the package via git repository to get fixed version.
The package I want is
https://github.com/jquense/react-widgets
So I tried
yarn add https://github.com/jquense/react-widgets.git
I get error:
error Package "undefined#undefined" doesn't have a "name".
Firstly, is this error a problem with my use of yarn or a problem with react-widgets repository? I am assuming it should work to add it like this so please correct me if I am wrong.
Also, can I assume that if there is an updated npm package, that I will be able to update with yarn at that time?
I'm afraid it is impossible to do now. This git repo is actually several packages inside(main package is here) one repo and root package.json is not valid one - it doesn't have name description and this is fail reason. There is discussion about supporting this in yarn, but it hasn't been implemented yet(in npm too).
Yarn creates a yarn.lock file after you perform a yarn install.
Should this be committed to the repository or ignored? What is it for?
Yes, you should check it in, see Migrating from npm
What is it for?
The npm client installs dependencies into the node_modules directory non-deterministically. This means that based on the order dependencies are installed, the structure of a node_modules directory could be different from one person to another. These differences can cause works on my machine bugs that take a long time to hunt down.
Yarn resolves these issues around versioning and non-determinism by using lock files and an install algorithm that is deterministic and reliable. These lock files lock the installed dependencies to a specific version and ensure that every install results in the exact same file structure in node_modules across all machines.
Depends on what your project is:
Is your project an application? Then: Yes
Is your project a library? If so: No
A more elaborate description of this can be found in this GitHub issue where one of the creators of Yarn eg. says:
The package.json describes the intended versions desired by the original author, while yarn.lock describes the last-known-good configuration for a given application.
Only the yarn.lock-file of the top level project will be used. So unless ones project will be used standalone and not be installed into another project, then there's no use in committing any yarn.lock-file – instead it will always be up to the package.json-file to convey what versions of dependencies the project expects then.
I see these are two separate questions in one. Let me answer both.
Should you commit the file into repo?
Yes. As mentioned in ckuijjer's answer it is recommended in Migration Guide to include this file into repo. Read on to understand why you need to do it.
What is yarn.lock?
It is a file that stores the exact dependency versions for your project together with checksums for each package. This is yarn's way to provide consistency for your dependencies.
To understand why this file is needed you first need to understand what was the problem behind original NPM's package.json. When you install the package, NPM will store the range of allowed revisions of a dependency instead of a specific revision (semver). NPM will try to fetch update the dependency latest version of dependency within the specified range (i.e. non-breaking patch updates). There are two problems with this approach.
Dependency authors might release patch version updates while in fact introducing a breaking change that will affect your project.
Two developers running npm install at different times may get the different set of dependencies. Which may cause a bug to be not reproducible on two exactly same environments. This will might cause build stability issues for CI servers for example.
Yarn on the other hand takes the route of maximum predictability. It creates yarn.lock file to save the exact dependency versions. Having that file in place yarn will use versions stored in yarn.lock instead of resolving versions from package.json. This strategy guarantees that none of the issues described above happen.
yarn.lock is similar to npm-shrinkwrap.json that can be created by npm shrinkwrap command. Check this answer explaining the differences between these two files.
You should:
add it to the repository and commit it
use yarn install --frozen-lockfile and NOT yarn install as a default both locally and on CI build servers.
(I opened a ticket on yarn's issue tracker to make a case to make frozen-lockfile default behavior, see #4147).
Beware to NOT set the frozen-lockfile flag in the .yarnrc file as that would prevent you from being able to sync the package.json and yarn.lock file. See the related yarn issue on github
yarn install may mutate your yarn.lock unexpectedly, making yarn claims of repeatable builds null and void. You should only use yarn install to initialize a yarn.lock and to update it.
Also, esp. in larger teams, you may have a lot of noise around changes in the yarn lock only because a developer was setting up their local project.
For further information, read upon my answer about npm's package-lock.json as that applies here as well.
This was also recently made clear in the docs for yarn install:
yarn install
Install all the dependencies listed within package.json
in the local node_modules folder.
The yarn.lock file is utilized as follows:
If yarn.lock is present and is enough to satisfy all the dependencies
listed in package.json, the exact versions recorded in yarn.lock are
installed, and yarn.lock will be unchanged. Yarn will not check for
newer versions.
If yarn.lock is absent, or is not enough to satisfy
all the dependencies listed in package.json (for example, if you
manually add a dependency to package.json), Yarn looks for the newest
versions available that satisfy the constraints in package.json. The
results are written to yarn.lock.
If you want to ensure yarn.lock is not updated, use --frozen-lockfile.
From My experience I would say yes we should commit yarn.lock file. It will ensure that, when other people use your project they will get the same dependencies as your project expected.
From the Doc
When you run either yarn or yarn add , Yarn will generate a yarn.lock file within the root directory of your package. You don’t need to read or understand this file - just check it into source control. When other people start using Yarn instead of npm, the yarn.lock file will ensure that they get precisely the same dependencies as you have.
One argue could be, that we can achieve it by replacing ^ with --. Yes we can, but in general, we have seen that majority of npm packages comes with ^ notation, and we have to change notation manually for ensuring static dependency version.But if you use yarn.lock it will programatically ensure your correct version.
Also as Eric Elliott said here
Don’t .gitignore yarn.lock. It is there to ensure deterministic dependency resolution to avoid “works on my machine” bugs.
Not to play the devil's advocate, but I have slowly (over the years) come around to the idea that you should NOT commit the lock files.
I know every bit of documentation they have says that you should. But what good can it possibly do?! And the downsides far outweigh the benefits, in my opinion.
Basically, I have spent countless hours debugging issues that have eventually been solved by deleting lock files. For example, the lock files can contain information about which package registry to use, and in an enterprise environment where different users access different registries, it's a recipe for disaster.
Additionally, the lock files can really mess up your dependency tree. Because yarn and npm create a complex tree and keep external modules of different versions in different places (e.g. in the node_modules folder within a module in the top node_modules folder of your app), if you update dependencies frequently, it can create a real mess. Again, I have spent tons of time trying to figure out what an old version of a module was still being used in a dependency wherein the module version had been updated, only to find that deleting the lock file and the node_modules folder solved all the hard-to-diagnose problems.
I even have shell aliases now that delete the lock files (and sometimes node_modules folders as well!) before running yarn or npm.
Just the other side of the coin, I guess, but blindly following this dogma can cost you........
I'd guess yes, since Yarn versions its own yarn.lock file:
https://github.com/yarnpkg/yarn
It's used for deterministic package dependency resolution.
Yes! yarn.lock must be checked in so any developer who installs the dependencies get the exact same output! With npm [that was available in Oct 2016], for instance, you can have a patch version (say 1.2.0) installed locally while a new developer running a fresh install might get a different version (1.2.1).
Yes, You should commit it. For more about yarn.lock file, refer the official docs here