Hi, On 11.12.20 23:40, Will Iverson wrote:
One of the biggest complaints about Maven has long been the verbosity of the XML format. The verbosity is due in large part to the exclusive reliance on XML elements in Maven.
Which I can't see. Only a few people are complainging about that... I would complain more about other issues (My personal opinion).
Proposal: Allow Maven pom.xml to treat attributes as a short-hand for declaring configuration elements.
If you would do that on build pom it might be possible to do that with the current path which is undergoing...
Example: One of the most verbose sections of the pom for most projects is dependencies. A typical example: <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.8.0</version> </dependency> Here is the same declaration expressed with attribute shortcuts: <dependency groupId="commons-io" artifactId="commons-io" version="2.8.0" /> That's an 80% reduction in LoC, and would make Maven comparable with other
Is this really the measure to reduce the LoC ?
popular build tools (e.g. compare and contrast with other build tools at https://mvnrepository.com/artifact/commons-io/commons-io/2.8.0)
Why should we compare to other build tools?
REQUEST: Feedback on if this is something to pursue. I've done some research, happy to submit patches, but don't want to pursue if there is either a) technical reason[s] not to proceed I'm not aware of or b) a lack of enthusiasm for the entire idea from the community. Basically, I'm looking for some feedback along the lines of a) love it - please submit patches so we can check it out, b) huh, maybe, willing to look at it, or c) this is a terrible idea, because X. Effectively, a totally non-binding vote on if this is worth exploring. I've discussed this with others online and done some research, so are a few answers to objections/Qs as I currently understand. I may be wrong/uninformed about certain aspects, which would be very helpful feedback. Q: Won't this require a new Maven XSD to be generated? A: No. The current Maven XSD declares many elements, but is not actually involved in validation. While the current XSD is valuable for tools and documentation, it does not actually perform validation. Q: Wait, so what actually does the validation? A: It's all done in Java code generated by Modello. The maven-model project (https://github.com/apache/maven/tree/maven-3.6.3/maven-model) relies on the Modello Maven Plugin ( http://codehaus-plexus.github.io/modello/modello-maven-plugin/) which in turn relies on Modello core (http://codehaus-plexus.github.io/modello/) to generate the Java code that processes the pom.xml The proposal is to submit a patch for Modello that would allow the generated source to accept an attribute as an alias for input. If it's a valid element per the Maven maven.mdo file ( https://github.com/apache/maven/blob/maven-3.6.3/maven-model/src/main/mdo/maven.mdo) it will now accept an attribute as a shortcut.
And what would be the result? Is it intended for the build or for the consumer pom ? The change itself not really the problem... The consquences are the point...
Q: Wouldn't this break, like, everything? A: It would only affect pom.xml files that are read at runtime. All emitted pom.xml files would remain exactly the same.
Which would break all tooling IDE's other toolings for example SonarQube, Jenkins etc.
Q: Does this involve changing or rewriting the user's pom.xml? Isn't that the thing that's making it hard to support alternative formats for pom.xml like polyglot poms, etc? A: Nope, the pom.xml on disk is still the pom.xml. A <prerequisites><maven>X.X.X<maven></prerequisites> would be the only flag recommended to declare that a pom.xml uses attributes for shorthand.
Polyglot only improves an inconvenience for some users which results in no support from your IDE/Tools in the end which reduces the acceptance.
Q: How much work is this to actually implement? A: It starts with a few lines added to the Modello code generation to allow for attribute aliasing with a feature flag. Testing those changes through the rest of the dependency chain. Adding test cases throughout. Documentation. although as "now you can use attributes" is conceptually simple it's not too bad. Tools in the Maven ecosystem would be able to indicate they have been updated to support this by referring to the simple term, "attribute shortcuts". Because nothing else changes, the only real documentation change would be "things that were elements can also be declared as attributes." The trickiest part is probably sorting out how to manage the feature flag across the various components. I'm sure there's more with a huge ecosystem like this, but the actual changes to the Modello code gen appear to be surprisingly minor.
As already written it breaks tooling / IDE's ... which should be reconsidered very carefully...
Q: What about tooling, like IDEs, publishing to Maven Central & Maven repositories, etc? A: Many IDEs appear to have implemented validation logic on top of Maven that currently will flag attributes as errors in a pom.xml. Those IDEs and other tools would require updates to this validation logic. Because the rendered pom.xml output remains the same publishing tool chains and Maven repositories should be completely unaffected.
Q: Any big issues you've identified? A: Many sub-elements are not actually processed by Modello or Maven Model, but are instead passed along to the plugin. For example, <configuration> elements. It would be up to each of these projects to eventually allow for attribute aliasing (or not). Maven projects that rely on Modello would have the choice to adopt the new version and turn on the feature flag (or not). It's possible that this would be confusing for some users - i.e. "why can I declare dependencies with attributes but not configuration values"? That said, I think it's manageable and would allow the ecosystem to slowly update. Q: Shouldn't we wait for Maven 5 to tackle this? A: There's an issue going back to 2008 about the verbosity of pom.xml - https://issues.apache.org/jira/browse/MNG-3397 - so... that's 12 years. While writing this email, I just realized I commented on that issue back in 2014. Any proposal to dramatically change the pom is going to be a *huge* effort and is not at all what I'm proposing. This is literally the simplest possible change I can think of that accomplishes the goal (dramatically reducing the verbosity of the pom.xml) with the least possible impact to the ecosystem. It's been twelve years. Maven 5 is years away.
So what know? The number of people working on Maven in general is limited they should focus on the most important problems...
I know there is a voting system for changes to Maven, and this would be a huge userland change.
This is biggest problem here. The change on the users side and acceptance of that change which is a really big step.... If there is even a soft exploratory "yes" I'm happy
to submit patches. Even better would be the assistance of an existing Maven committer willing to help me navigate Apache requirements. If the feedback is generally negative, that's fine too - I'll just go ahead and close the issue. What I don't want to do is submit patches and then have everyone yell at me. The Internet can be rough, you know. :) I know this is a long email - thanks for reading, and looking forward to feedback.
The point is based on the current direction something like is made possible in the future.... Kind regards Karl Heinz Marbaise --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org For additional commands, e-mail: dev-h...@maven.apache.org
