Required model fields vs validation

[slawekjaranowski]

Validated fields (15 / 28)

Path	Stage	Notes
project.modelVersion	raw + effective
project.groupId	raw	Conditionally required — only when <parent> is absent
project.artifactId	raw + effective
project.version	raw + effective	Conditionally required — only when <parent> is absent
project.parent.groupId	raw
project.parent.artifactId	raw
project.dependencies.dependency.groupId	effective
project.dependencies.dependency.artifactId	effective
project.dependencies.dependency.exclusions.exclusion.groupId	effective
project.dependencies.dependency.exclusions.exclusion.artifactId	effective
project.repositories.repository.id	raw
project.repositories.repository.url	raw
project.build.plugins.plugin.artifactId	raw
project.reporting.plugins.plugin.groupId	effective	Marked required but has default org.apache.maven.plugins
project.reporting.plugins.plugin.artifactId	effective

Missing validations (11 / 28)

Path	Notes
project.name	Not validated anywhere
project.inceptionYear	Not validated anywhere
project.build	Object association — null not checked
project.build.sourceDirectory	Has SuperPOM default — may be intentional
project.build.scriptSourceDirectory	Has SuperPOM default — may be intentional
project.build.testSourceDirectory	Has SuperPOM default — may be intentional
project.build.extensions.extension.groupId	No validation at all
project.build.extensions.extension.artifactId	No validation at all
project.profiles.profile.build	Object association — null not checked
project.profiles.profile.activation.property.name	Not validated
project.reporting.plugins.plugin.reportSets.reportSet.reports	Not validated

Fields incorrectly marked as required in MDO — optional when <parent> is present

These fields can be inherited from the parent POM.
The MDO definition should be corrected.

Path	Notes
project.groupId	Optional when <parent> is present — inherited from parent
project.version	Optional when <parent> is present — inherited from parent

Fields incorrectly marked as required in MDO — always have a default value

These fields are marked <required>true</required> but also define a <defaultValue>,
so they are never actually empty. The required annotation is misleading.

Path	Default value	Validated
project.profiles.profile.id	"default"	no — unnecessary given the default
project.reporting.plugins.plugin.groupId	"org.apache.maven.plugins"	yes — unnecessary given the default
project.reporting.plugins.plugin.reportSets.reportSet.id	"default"	no — unnecessary given the default

Most actionable gaps

• project.build.extensions.extension.groupId/artifactId — build extensions have no coordinate
  validation at all, unlike plugins which do validate coordinates.
• project.profiles.profile.activation.property.name — an activation property without a name
  silently has no effect.
• project.reporting.plugins.plugin.reportSets.reportSet.reports — report sets are not
  validated.

Fields validated but NOT marked required in MDO

These are likely intentional and should remain as-is:

Path	Default value	Reason
project.parent.version	—	Effectively required for resolution
project.build.plugins.plugin.groupId	"org.apache.maven.plugins"	Validated for safety even though it has a default

[hboutemy]

thinking at it, I fear we have one issue: pom.xml content vs effective POM content
we'll have to clarify

[slawekjaranowski]

From modello model we generate a xsd .... which can be used in editors so it can be less restricted.

Another issue is like for project.name, inceptionYear should be not required in model.

[slawekjaranowski]

• Remove redundant required attributes from Maven model #11985

[hboutemy]

From modello model we generate a xsd .... which can be used in editors so it can be less restricted.

in fact, now I get that we use the xsd in a raw POM situation (= build pom.xml in source control) = what I imagine you call "less restricted"
and to me, the POM is the effective POM
we'll have to just document that clearly, with clear pointer on field where this makes a difference on some aspect (like required)

I know for a long time that we never had Modello generate code based on the "required" attribute of a field, because there was clearly a problem, that was never described: we're now starting to describe the problem (by retro documenting what checks are handwritten in the effective model building process)

on project.name, I'm surprised it's not required: is there a default value?

on inceptionYear, i'm less surprised

[slawekjaranowski]

on project.name, I'm surprised it's not required: is there a default value?

default value is artifactId - detected in MavenProject

[slawekjaranowski]

Even more project.name is not present in V4 - https://github.com/apache/maven/blob/a5558f892dff1d401e95a6e81a0cea4a950a6c96/api/maven-api-core/src/main/java/org/apache/maven/api/Project.java

[hboutemy]

Even more project.name is not present in V4

you're comparing the API for plugins vs the POM: not the same, org.apache.maven.api.model.Model still has the name field
Like raw POM not the same as effective POM