#1130: improve using variable FAIL_ON_AMBIGOUS_MERGE incl. documentat…

[hohwille]

fixes #1130
improvement for PR #1138

• improve using variable FAIL_ON_AMBIGOUS_MERGE
• add documentation
• add test
• follow best-practice to have test (XmlMergerTest) in the same package as the tested class (XmlMerger)
• also renamed the package com.devonfw.tools.ide.merge.xmlmerger to com.devonfw.tools.ide.merge.xml following DRY principle.

[coveralls]

Pull Request Test Coverage Report for Build 13999873361

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.07%) to 67.738%

---

Totals
Change from base Build 13998949209:	0.07%
Covered Lines:	7838
Relevant Lines:	11144

---

💛 - Coveralls

[hohwille]

Successfully tested with latest SNAPSHOT (2025.03.002-20250327.024013-7):
By default the error is gone (PR #1138).
After adding the following line to conf/ide.properties:

FAIL_ON_AMBIGOUS_MERGE=true

I could get this from ide intellij:

Start: Configuring workspace main for IDE intellij
Failed to merge workspace file D:\projects\IDEasy\workspaces\main\.idea\workspace.xml with update template D:\projects\IDEasy\settings\intellij\workspace\update\.idea\workspace.xml and setup file D:\projects\IDEasy\settings\intellij\workspace\setup\.idea\workspace.xml!
com.devonfw.tools.ide.merge.xml.XmlMergeException: Merge strategy combine failed on /project[@version='4']/component[@name='RunManager']
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy.merge(XmlMergeStrategy.java:68)
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy.combineChildNodes(XmlMergeStrategy.java:112)
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy$1.doMerge(XmlMergeStrategy.java:29)
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy.merge(XmlMergeStrategy.java:64)
        at com.devonfw.tools.ide.merge.xml.XmlMerger.merge(XmlMerger.java:123)
        at com.devonfw.tools.ide.merge.xml.XmlMerger.doMerge(XmlMerger.java:82)
        at com.devonfw.tools.ide.merge.FileMerger.merge(FileMerger.java:50)
        at com.devonfw.tools.ide.merge.DirectoryMerger.merge(DirectoryMerger.java:69)
        at com.devonfw.tools.ide.merge.DirectoryMerger.merge(DirectoryMerger.java:73)
        at com.devonfw.tools.ide.merge.DirectoryMerger.merge(DirectoryMerger.java:73)
        at com.devonfw.tools.ide.tool.ide.IdeToolCommandlet.mergeWorkspaceSingle(IdeToolCommandlet.java:103)
        at com.devonfw.tools.ide.tool.ide.IdeToolCommandlet.mergeWorkspace(IdeToolCommandlet.java:90)
        at com.devonfw.tools.ide.tool.ide.IdeToolCommandlet.configureWorkspace(IdeToolCommandlet.java:72)
        at com.devonfw.tools.ide.tool.ide.IdeToolCommandlet.run(IdeToolCommandlet.java:48)
        at com.devonfw.tools.ide.context.AbstractIdeContext.applyAndRun(AbstractIdeContext.java:958)
        at com.devonfw.tools.ide.context.AbstractIdeContext.run(AbstractIdeContext.java:876)
        at com.devonfw.tools.ide.cli.Ideasy.runOrThrow(Ideasy.java:95)
        at com.devonfw.tools.ide.cli.Ideasy.run(Ideasy.java:59)
        at com.devonfw.tools.ide.cli.Ideasy.main(Ideasy.java:133)
        at java.base@21.0.2/java.lang.invoke.LambdaForm$DMH/sa346b79c.invokeStaticInit(LambdaForm$DMH)
Caused by: java.lang.IllegalStateException: 2 matches found for XPath configuration[@default='true' and @type='JUnit'] in workspace XML at /project[@version='4']/component[@name='RunManager' @selected='JUnit.EnvironmentVariablesTest.testGetToolVariable']
        at com.devonfw.tools.ide.merge.xml.matcher.IdComputer.evaluateExpression(IdComputer.java:73)
        at com.devonfw.tools.ide.merge.xml.matcher.ElementMatcher.matchElement(ElementMatcher.java:61)
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy.combineChildNodes(XmlMergeStrategy.java:106)
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy$1.doMerge(XmlMergeStrategy.java:29)
        at com.devonfw.tools.ide.merge.xml.XmlMergeStrategy.merge(XmlMergeStrategy.java:64)
        ... 19 more

Your workspace configuration failed with 1 error(s) - see log above.
This is either a configuration error in your settings git repository or a bug in IDEasy.
Please analyze the above errors with your team or IDE-admin and try to fix the problem.
In order to prevent you from being blocked, you can start your IDE anyhow but some configuration may not be in sync.
Option 1: yes
Option 2: no