[MNG-8097] Validate that each dependency->type is a type registered in an artifact handler

[jira-importer]

Konrad Windszus opened MNG-8097 and commented

Currently often the dependency's type is being set to the extension and the resolution is lenient, i.e. if there is no artifact handler defining the value given in dependency->type resolution transparently uses the type as extension.
That can potentially lead to two issues:

1. Resolution might fail with surprising error messages like

Could not resolve dependencies for project ....: The following artifacts could not be resolved: <gav>: Could not transfer artifact <groupId>:<artifactId>:<unknown-type>:<version> from/to ...

This is an issue for all types not defined by Maven Core itself, e.g. for https://jackrabbit.apache.org/filevault-package-maven-plugin/index.html which registers an artifact handler for type content-package with extension zip.
2. The information addedToClasspath, includesDependencies and classifier from the artifact handler is not evaluated

Compare with https://maven.apache.org/repositories/artifacts.html#but-where-do-i-set-artifact-extension

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Remote Links:

• GitHub Pull Request #529
  

[jira-importer]

Konrad Windszus commented

Hervé Boutemy WDYT?

[jira-importer]

Hervé Boutemy commented

by "validate", you mean "fail with a message on unknown dependency types" and "force user to declare an extension that defines dependency type via an artifact handler"?

this will be more complex to users, who for example are used to using "zip" (non-existent) dependency type in a lazy way

perhaps something for Maven 4?

[jira-importer]

Konrad Windszus commented

By validate I mean "warn with a message on unknown dependency types".
Which artifact handler has "zip" as extension? I would assume something like this is provided by https://maven.apache.org/plugins/maven-assembly-plugin/...

[jira-importer]

Tamas Cservenak commented

You again mix things:

• (dependency) type is for downstream consumers. In project, when consuming just declare the dependency type of "zip" and be done with it.
• when building you declare packaging "content-package"

Do not try to enforce packaging on consumer side, or type on producer side as it makes no sense.

[jira-importer]

Konrad Windszus commented

when consuming just declare the dependency type of "zip" and be done with it.

No, as then the addedToClasspath, includesDependency and default classifier settings from the artifact handler are not considered!

[jira-importer]

Tamas Cservenak commented

If you do want to consume custom packaging with special instructions, then yes, you have to extend maven (usually by adding build extension) that adds requires type handlers.

But no, there is no "each dependency type is registered" type of thing, nor it makes sense. It is the developer who knows what he wants to achieve IMHO.

[jira-importer]

Konrad Windszus commented

But no, there is no "each dependency type is registered" type of thing, nor it makes sense.

For me it would make a lot of sense to enforce this, because otherwise the lenient handling of Maven being able to deal with both type and extension for dependencies leads to a lot of confusion and confusing follow-up errors as stated in the description.

[jira-importer]

Hervé Boutemy commented

perhaps just adding an INFO message "using default extension = type, addedToClasspath=false, includesDependency=false for dependency xxx"?
not really a warning, just a fact