I have received this kind error a couple of time before with different packages, usually i just try a combination of different versions till i finally get a match that works. Is there a way to know what package versions are compatible instead of using the trial error approach which is outright time consuming and exhausting.
Initially i though it could be that one of the packages depends on the other, like in this case maybe flutter_svg depends on a different version of flutter_luban so the version in my pubspec clashes with it, but none of these packages depend on one another after viewing the respective package dependencies.
pub get failed (1; So, because sakaHapa depends on both
flutter_svg ^0.17.4 and flutter_luban ^0.1.13, version solving
failed.)
You can use 'pub outdated' command like below.
https://dart.dev/tools/pub/cmd/pub-outdated
Here is column what means.
Current
The version used in your package, as recorded in pubspec.lock. If the package isn’t in pubspec.lock, the value is -.
Upgradable
The latest version allowed by your pubspec.yaml file. This is the version that dart pub upgrade resolves to. The value is - if the value in the Current column is -.
Resolvable
The latest version that can be resolved, when combined with all other dependencies. This version corresponds to what dart pub upgrade gives you if all version constraints in pubspec.yaml are unbounded. A value of - means that the package won’t be needed.
Latest
The latest version of the package available, excluding prereleases unless you use the option --prereleases.
flutter pub outdated
Related
We have decided to upgrade the Flutter version from 1.22 to 2.0 (migrating to null-safety) in an existing project.
We checkout Flutter v2.0.0 and then run the following command:
dart pub upgrade --null-safety
Flutter nicely resolves all dependency conflicts and sets new versions for packages.
Without changing min environment SDK in pubspec.yaml (staying at ">2.10.0 <3.0.0") we fix all breaking changes in the code.
All errors in vs code disappear so we can compile the code. But, when we do compile we get errors from packages e.g. reorderables, fl_chart, flutter_svg etc. stating some classes are undefined. It seems like packages were compiled with a higher SDK version and they weren't set min SDK version to match the one that they were compiled with.
So the package states it can be compiled with Flutter 2.10.0 but in reality, it fails to compile because in this version of Flutter it is missing some necessary imports.
My question is, is this a problem of packages or a problem in my way of processing with migration?
Is it that packages are lacking properly set min SDK?
My conclusion is that most packages are lacking correctly set SDK version constraints. It seems authors usually compile packages for a certain version and do not check min SDK version required. When running dependency resolver it seems to solve dependencies but in compile time it fails.
dependencies:
test: ^1.19.3
I had my test dependency purposely downgraded.In my package, test's constraints were ^1.19.3. After I ran dart pub upgrade, it upgraded my test to 1.20.0 and it was visible in pubspec.lock even if my app depended on ^1.19.3 it kept it as it is and ignored it.
This is as intended: the ^ symbol indicates packages up to the next major version (in your example up to version 2.0.0) will upgrade with pub upgrade. If you want to lock to an exact version (not recommended) then you just remove the caret symbol (^).
See here for more details.
What is the difference between the "Upgradable" and "Resolvable" columns in the output of "dart pub outdated"?
Here is an example of a package that can be upgraded to the latest. The Upgradable, Resolvable, and Latest all match:
url_launcher *6.0.11 6.0.12 6.0.12 6.0.12
Here is an example of a package that is already at the highest resolvable version, but can't be upgraded to the absolute latest version. Presumably another dependency is restricting the resolvability to the latest.
rxdart *0.26.0 *0.26.0 *0.26.0 0.27.2
Here is an example of a package that can't be upgraded any higher but has a Resolvable version that is higher. What does this mean? How is this different from the middle case above?
provider *5.0.0 *5.0.0 6.0.1 6.0.1
In addition to the other very useful posted thoughts, I have learned the following helpful details:
Upgradable refers to the highest version that your direct pubspec will permit, which considers the sdk version and the individual package version (whether to upgrade to just minor or also major). When Upgradable is limited, it can likely be your sdk version holding things back. In my case I was using sdk 2.12, but some packages require 2.14 now (Sep 2021).
From the docs:
The latest version allowed by your pubspec.yaml file. This is the version that dart pub upgrade resolves to. The value is - if the value in the Current column is -.
Resolvable refers to the highest version that all of the other packages' dependencies will allow, in addition to your direct pubspec constraints. When the Resolvable is limited, there is usually one package holding everything back, or a major version holding everything back.
From the docs:
The latest version that can be resolved, when combined with all other dependencies. This version corresponds to what dart pub upgrade gives you if all version constraints in pubspec.yaml are unbounded. A value of - means that the package won’t be needed.
Upgradable means an upgradeable version. Generally, minor version updates can be upgraded directly without modification.
Resolvable can use the version, generally a major version update (the 0.x version may have destructive changes, same as major version), may have incompatible interfaces to the previous version, if you update this version, you may need to change some code
Latest The latest version. If it is inconsistent with the Resolvable version, means the SDK version required by the latest version is inconsistent with the current project
The main difference is that Resolvable mains the version you need to reach to resolve outdated issues in your project and Upgradable mains the version you can update of that package.
To resolve it you must find packages you can update and continue updating until you can update the main package.
You can see it in this link about those concepts: Dart pub outdated
I am using analyser 1.7.1. The latest build_runner build command generates the following error.
flutter packages pub run build_runner build Failed to precompile
build_runner:build_runner:
../../../sdk/flutter/.pub-cache/hosted/pub.dartlang.org/analyzer-1.7.1/lib/src/error/best_practices_verifier.dart:1998:14:
Error: A non-null value must be returned since the return type
'String' doesn't allow null. String get displayString {
The usual flutter clean and pub cache repair commands don't seem to be fixing the problem, and displayString doesn't appear anywhere in my codebase.
There's an issue open 9 days ago. Here's the key part:
Right now, the current state of affairs is that:
package:analyzer 1.7.0 requires package:meta ^1.4.0
package:analyzer 1.7.1 has the same contents as 1.7.0, but requires package:meta ^1.3.0
Flutter stable pins package:meta to 1.3.0
I'm uncertain how we're running into the exceptions above - the two most recent versions of analyzer are pretty explicit about which version of meta they need.
#edlman do you have any dependency_overrides in your pubspec?
you're right, I'm using 3rd party pkgs which depend on meta 1.4.0 so I put it to dependency_overrides to solve the collision. It didn't come to my mind it cause such a problem.
I've changed the override to 1.3.0, it works fine, no problem yet
So I'd suggest checking whether or not there's a dependency_overrides in your pubspec, too.
It's a problem with analyser 1.7.1.
Add
dependency_overrides:
analyzer: 1.7.0
to pubspec.yaml.
There are more details available in raina77ow's answer.
I am modifying my default template file from my flutter installation directory here
C:\src\flutter\flutter\packages\flutter_tools\templates\app\pubspec.yaml.tmpl
dependencies:
#omitted
cupertino_icons: ^0.1.3
mobx: latest
flutter_mobx: latest
I am getting this error
Invalid version constraint: Could not parse version "latest". Unknown text at "latest".
How do i get the latest version instead of specifying specific version like ^1.x.x
There is no latest, you have to specify the version number or you can use any:
any
The string any allows any version. This is equivalent to an empty version constraint, but is more explicit. Although any is allowed, we don’t recommend it.
https://dart.dev/tools/pub/dependencies
To update your dependencies to the latest version you can do the following:
Use pub upgrade to update to the latest package versions that your pubspec allows. To identify dependencies in your app or package that aren’t on the latest stable versions, use pub outdated.
try this after the package that you want the latest
http: ^{latest version}