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https://issues.apache.org/jira/browse/MNG-7044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17246131#comment-17246131
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Will Iverson commented on MNG-7044:
-----------------------------------
Looks like the change would be to this file:
https://github.com/codehaus-plexus/modello/blob/08152b14bb44867c038e52fc957c46ec1906668e/modello-plugins/modello-plugin-xpp3/src/main/java/org/codehaus/modello/plugin/xpp3/Xpp3ReaderGenerator.java
It's a ~1600 line code generator. Looks like it doesn't actually have any tests
for validating that a given pom.xml can be parsed/validated, just that the
files generated by a *.mdo file can successfully compile. The maven-model
project at https://github.com/apache/maven/blob/master/maven-model/pom.xml has
a dependency on modello-maven-plugin, which in turn uses the above.
Trying to time box to ~1hr at time. :) Next step is to try to generate a
working test environment linking the above with SNAPSHOTs.
My sense that this will all boil down to just a few lines to tweak the
Xpp3ReaderGenerator.java is still there. The error message for an invalid
pom.xml such as:
Malformed POM /Users/wiverson/src/tiny-pom/pom.xml: Unknown attribute 'scope'
for tag 'dependency' (position: START_TAG seen ...y groupId="junit"
artifactId="junit" version="4.11" scope="test"/>... @22:81) @
/Users/wiverson/src/tiny-pom/pom.xml, line 22, column 81
...is clearly coming from the Modello generated code, not the XSD. A simple
version of the tweak to the code generator would just check to see if the
attribute is a known field and allow it to be set if known, while throwing an
error (like today) if not. A fancier version would emit an warning for a
duplicate attribute/element declaration (just like a duplicate element
declaration today.
> Allow use of attributes in Maven pom.xml
> ----------------------------------------
>
> Key: MNG-7044
> URL: https://issues.apache.org/jira/browse/MNG-7044
> Project: Maven
> Issue Type: New Feature
> Components: core, POM
> Reporter: Will Iverson
> Priority: Minor
> Labels: features
>
> Proposal: The current pom.xml file is very verbose due to the exclusive use
> of XML elements. This makes even simple declarations such as dependencies
> unnecessarily verbose.
> I would propose that a future version of Maven allow for the use of
> attributes as an alternative declaration for pom.xml configuration. This
> would only affect how Maven ingests project files - for consistency and
> backward compatibility all generated pom.xml files would continue to be
> element based.
> Projects that declared a conflicting/duplicate attribute/element pairing
> would be considered to be malformed, and would result in a built break.
> By way of example of the benefit of this proposal, this declaration would be
> reduced from:
> <dependency>
> <groupId>commons-cli</groupId>
> <artifactId>commons-cli</artifactId>
> <version>1.4</version>
> </dependency>
> ...to...
> <dependency groupId="commons-cli" artifactId="commons-cli" version="1.4" />
> This would allow many Maven projects to *dramatically* decrease the total
> line count, which is one of the frequent criticisms of Maven compared with
> other build tools.
> If there is interest, I would be happy to help support this. My
> hope/expectation is that the changes required to support this in Maven itself
> would be quite minor - simply adding a bit of additional logic to look for
> attributes in the XML parse and error reporting in the event of a duplication
> (as well as supporting test cases). That said, I don't want to send in
> patches for a change like this that would be dead on arrival.
> This would, of course, represent a potentially large impact on the user and
> tooling space (in particular, IDEs that integrate Maven support). As the
> emitted files for resolved pom.xml files (those that are published in repos)
> would remain the same, hopefully the overall impacts would be manageable.
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