Maven importer should support custom POM filenames or honor maven.pomfile.globPattern

[lilithyang2018]

Problem

A Maven Java project uses pom-customize.xml instead of pom.xml.

Maven itself works:

mvn -f pom-customize.xml compile

The VS Code Maven extension can be configured to discover it:

{
  "maven.pomfile.globPattern": "**/{pom.xml,pom-customize.xml}"
}

But the Java language server does not import the Maven classpath from pom-customize.xml. Java files then show false diagnostics such as:

RestController cannot be resolved to a type

Example import:

import org.springframework.web.bind.annotation.RestController;

## Expected behavior

The Java language server should either:

1. Honor maven.pomfile.globPattern, or
2. Provide a Java setting such as java.import.maven.pomfile.globPattern, or
3. Support custom Maven POM file names when Maven for Java has already discovered them.

## Actual behavior

Maven Explorer can discover the custom POM, but JDT LS / Red Hat Java does not import the project classpath unless the build file is named pom.xml.

## Environment

- VS Code
- Extension: redhat.java version 1.55.0
- Extension: vscjava.vscode-maven version 0.45.3
- Java: 21
- Maven project file: pom-customize.xml
- No pom.xml in project root

## Workarounds tried

- maven.pomfile.globPattern
- maven.executable.options: -f pom-customize.xml
- .mvn/maven.config with -f pom-customize.xml

These help Maven commands/explorer, but do not fix Java language server diagnostics.

[datho7561]

I don't think this is very high priority. Maven assumes the pom is called pom.xml, so anything other than that is unexpected. Unless if there's multiple poms in the same directory, you could rename the existing pom to pom.xml to get it working.

As far as I can tell, m2e doesn't have a way to configure this, so it'll require work upstream to implement it. (m2e is the project we use to import Maven projects).