英文:
Why does the use of dependencyManagement in maven usually not lead to problems?
问题
我了解在Maven中，dependencyManagement可以在避免子项目中出现不同版本的依赖以及只使用一个（且仅有一个）版本的依赖方面带来很大的好处。
与此同时，我很难理解为什么通过dependencyManagement来覆盖传递依赖是安全的做法。
假设我们有一个依赖D，在dependencyManagement中设置为版本2.0。
另一个依赖 - C - 也使用了D，尽管它依赖于版本1.0的D。
通过dependencyManagement，我将这个传递性依赖设置为了2.0。
这不是很危险吗？毕竟，C 依赖于版本1.0的API和实现 - 如果在版本1.0和2.0之间进行了破坏性更改，会怎么样呢？
英文:
I understand that dependencyManagement in Maven gives you great benefits in terms of avoiding different versions of dependencies in sub-poms and in using one (and only one) version of a dependency.
At the same time, I am struggling to understand why overriding transitive dependencies by dependencyManagement is a safe thing to do.
Let's say that we have a dependency D which is set to version 2.0 with dependencyManagement.
Another dependency - C - also uses D, although it depends on D in version 1.0.
With dependencyManagement, I am setting this transitive dependency up to 2.0.
Isn't this dangerous? After all, C relies on the API and the implementation of version 1.0 - what if breaking changes have been made between the versions 1.0 and 2.0 of D?
答案1
得分: 1
这是一个不安全的操作。
这可能会导致你所描述的问题。
但是由于你不能拥有多个版本的依赖项（至少不能没有阴影），你需要选择一个版本或让Maven来决定。后者在大多数情况下比自己选择一个合理的版本更加危险。
英文:
It is not a safe thing to do.
It can lead to the problems you describe.
But as you cannot have more than one version of a dependency (at least, not without shading), you need to pick one or let Maven decide. The latter is in most cases more dangerous than picking a reasonable version yourself.
答案2
得分: 1
它之所以可行，是因为 D 2.0 具备向后兼容性。
因此 D 2.0 提供了与 D 1.0 相同的所有 API 和功能，因此 C 可以使用它。
如果 D 2.0 不 具备向后兼容性，那么就会出现冲突。您可能需要升级 C，或者找到一个较低版本的 D，使得您的所有依赖项都可以愉快地依赖于它。
您可以使用 mvn dependency:tree 来解决冲突，如 这里所述。
英文:
It works because D 2.0 is backward compatible.
So D 2.0 provides all APIs, functionalities as D 1.0, and thus C can use it.
If D 2.0 is not backward compatible, then you have a conflict. You might need to upgrade C, or find a lower version of D that all your dependencies can happily rely on.
You can use mvn dependency:tree to resolve conflicts as mentioned here
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