[MCOMPILER-317] Plugin generates wrong modulepath (dependencies listed in wrong order)

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.7.0

Environment

Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T03:58:13-04:00)
Maven home: C:\Program Files\apache-maven-3.5.2\bin\..
Java version: 9.0.1, vendor: Oracle Corporation
Java home: C:\Program Files\Java\jdk-9.0.1
Default locale: en_CA, platform encoding: Cp1252
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"

• Assignee: Unassigned
• Reporter: Gili
• Created: 06/Dec/17 08:26
• Updated: 24/Feb/18 18:31

Description

Testcase: https://github.com/cowwoc/maven-java9-class-shadowing

If a project contains dependencies with the same module name (which is valid according to https://stackoverflow.com/a/46573805/14731) then maven-compile-plugin invokes javac with a modulepath containing dependencies in an (apparently) arbitrary order. If I place the project in one directory, I get one order. If I place the project in another directory, I get another order. This is 100% reproducible across multiple runs, across different computers.

I suspect that somewhere deep inside the code someone is using HashMap which is leading to undefined iteration order depending on the path being used.

Expected behavior: dependencies should be listed in the same order as declared in pom.xml (see https://stackoverflow.com/a/793193/14731)

Actual behavior: regardless of whether I list ExtensionPresent before or after MyLibrary, the wrong order gets passed to javac.

Issue Links

• relates to: MNG-6357 Dependency order should be nearest first