This project was created to have a look into how the -pl option works.

Project Structure

aggregation
├── README.md
├── moduleA
│   ├── pom.xml
│   └── src
│       ├── main/java/dummy
│       │   └── AppA.java
│       └── test/java/dummy
│           └── AppATest.java
├── moduleB
│   ├── pom.xml
│   └── src
│       ├── main/java/dummy
│       │   └── AppB.java
│       └── test/java/dummy
│           └── AppBTest.java
├── moduleC
│   ├── pom.xml
│   └── src
│       ├── main/java/dummy
│       │   └── AppC.java
│       └── test/java/dummy
│           └── AppCTest.java
└── pom.xml

Module Relations

All modules A,B,C are sub-modules of the root aggregation module
Modules A and B define aggregation module as their parent
Module B defines C as its depedendency

Building the modules

Builds are all invoked from the aggregation dir

Building without -pl

Command: mvn clean package Result: Modules built: aggregation, A, C, B

Building with -pl

Command: mvn clean package -pl . Result: Modules built: aggregation

Building with -pl and -am

Command: mvn clean package -pl . -am Result: Modules built: aggregation

Building with -pl, -am and -amd

Command: mvn clean package -pl . -am -amd Result:

Modules identified to be built: aggregation, A, B
Build fails: Failed to execute goal on project moduleB: Could not resolve dependencies for project dummy:moduleB:jar:1.0-SNAPSHOT: Could not find artifact dummy:moduleC:jar:1.0-SNAPSHOT

Notes

Seems that child projects are identified as dependants (thus -amd picks them up).
Seems that sub-modules are not identified as dependencies in the aggregate module (thus -am doesn't pick them up)

chkypros/aggregation