Document that spring-boot:repackage should not be run from the command-line

[jmaasing]

This is exactly the same as reported #19055

Environment:

mvn -V
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
¨Java version: 14.0.1, vendor: Azul Systems, Inc.,
Default locale: en_SE, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.5", arch: "x86_64", family: "mac"

How to reproduce

Go to https://start.spring.io/
Select Maven, Java, 2.3.1, Jar, Java 14.
Unpack the downloaded zip file and go into the directory:
Type:
mvn clean package

wait for it to finish, then type:
mvn spring-boot:repackage

I get the following error:

[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.3.1.RELEASE:repackage (default-cli) on project demo: Execution default-cli of goal org.springframework.boot:spring-boot-maven-plugin:2.3.1.RELEASE:repackage failed: Source file must not be null -> [Help 1]

Workaround

Run mvn clean package spring-boot:repackage

[wilkinsona]

Thank you, @jmaasing. Sorry, I see now that this is indeed exactly the same as #19055. I misread things earlier. We have precise steps to reproduce the problem now though (thank you for that) so let's keep this one open as we're better-placed to investigate.

[wilkinsona]

@jmaasing As @snicoll asked the raiser of #19055 can you please help us to understand your use case for calling the spring-boot:repackage goal in isolation rather than relying upon it being bound to the package phase?

[jmaasing]

For my use case I can bind it to the package phase if needed. The way I ended up testing this is because I have a parent-POM that builds not only the spring boot application but also other things and wanted to add the re-packaging as a separate step in the build pipeline.

I could not find anything in the documentation indicating that this goal can not be run separately. Neither when I do mvn spring-boot:help or on https://docs.spring.io/spring-boot/docs/current/maven-plugin/reference/html/#using

So maybe it's just a case of improving documentation that this goal can not be run from the command line unless you also do package.