Reinstate META-INF/maven/${groupId}/${artifactId}/pom.xml in published jar files

[dsyer]

Somewhere between 2.0.0.M6 and 2.0.0.RELEASE the spring-boot jars stopped having their pom.xml included:

$ jar -tvf ~/.m2/repository/org/springframework/boot/spring-boot/2.0.0.RELEASE/spring-boot-2.0.0.RELEASE.jar | grep pom
$ jar -tvf ~/.m2/repository/org/springframework/boot/spring-boot/2.0.0.M6/spring-boot-2.0.0.M6.jar | grep pom
   104 Mon Nov 06 05:56:56 GMT 2017 META-INF/maven/org.springframework.boot/spring-boot/pom.properties
 13521 Mon Nov 06 05:55:14 GMT 2017 META-INF/maven/org.springframework.boot/spring-boot/pom.xml

Since including the pom.xml is a standard feature of the Maven JAR plugin, it seems like this might be unintended. Maybe something to do with the maven-flatten-plugin (but that first showed up in 2.0.0.M4)?

[wilkinsona]

The pom is there in RC2 as well so it seems to have disappeared due to something that changed between RC2 and RELEASE.

[dsyer]

Looks like probably this:

spring-boot/spring-boot-project/spring-boot-parent/pom.xml

Line 602 in 84c8f38

<addDefaultImplementationEntries>false</addDefaultImplementationEntries>

[wilkinsona]

I think that one affects the manifest. It's this one that's switching off the pom I think:

spring-boot/spring-boot-project/spring-boot-parent/pom.xml

Line 600 in 84c8f38

<addMavenDescriptor>false</addMavenDescriptor>

[dsyer]

Yes. Part of this: #11994 (although it looks like maybe unrelated collateral damage to me).

[wilkinsona]

Removing that line restores the pom and doesn't seem to make any difference to the manifest. This is 2.0.5.RELEASE:

Manifest-Version: 1.0
Implementation-Title: Spring Boot
Automatic-Module-Name: spring.boot
Implementation-Version: 2.0.5.RELEASE
Built-By: Spring
Created-By: Apache Maven 3.5.4
Build-Jdk: 1.8.0_141

And this is 2.0.x with that line removed:

Manifest-Version: 1.0
Implementation-Title: Spring Boot
Automatic-Module-Name: spring.boot
Implementation-Version: 2.0.6.BUILD-SNAPSHOT
Built-By: Spring
Created-By: Apache Maven 3.5.4
Build-Jdk: 1.8.0_181

[wilkinsona]

I suspect it's collateral damage too. Flagging for team attention just in case I'm overlooking something.

[philwebb]

I think I removed it because it seemed a little unnecessary and I wanted to align with what Framework does. Do we need them back for a specific reason?

[dsyer]

Do we need them back for a specific reason?

I was just surprised not to see them since they are "standard". Also I assert their presence in tests in the thin launcher, but I can change that if I have to. I think it is good to have them, in case there are static analysis tools that want to know the transitive dependencies.

[philwebb]

I think I'd rather keep them out to align with the jars published by Spring Framework. I guess the build system might play a big part in whether they are there or not. Maven probably adds them, Gradle probably doesn't.

Another reason not to add them back is because we flatten then and remove a few some bits. I've no idea if the flattened or orginal POM gets added, but its certainly easier our end to simply leave them out.