#992: support multiple attributes for merge

[JoelAdbu]

This PR fixes #992

Implemented changes:

• added support for multi-attribute merge identifiers, e.g. merge:id="@default,@type"
• added support for automatically using all element attributes via merge:id="@@"
• added tests covering the new merge id pattern

---

Testing instructions

Please add conscise, understandable instructions on how a reviewer can test/verify the functionality of your contribution here:

1. Checkout this branch.

2. Run all tests in IdComputerTest and execute:

build-local-dev.sh

3. Create a fresh project:

ide create <test-project> -

4. Clone any repository into worspace/main and run:

ide intellij

5. Verify that the existing XML merge still works with the current XPath-based workaround:

<configuration default="true"
               type="JUnit"
               factoryName="JUnit"
               merge:id="configuration[@default='true' and @type='JUnit']">

6. Modify the template in: project/<your-project>/settings/intellij/workspace/update/.idea/workspace.xml to use a multi-attribute merge identifier:

<configuration default="true"
               type="JUnit"
               factoryName="MyJUnit"
               merge:id="@default,@type">

7. Run

ide intellij

8. Verify that the existing configuration is identified using only the default and type attributes. Although factoryName differs, the element should still be matched and merged.

9. Modify the same configuration again to use:

 <configuration default="true"
               type="JUnit"
               factoryName="MyJUnit"
               merge:id="@@">

10. Run:

ide intellij

11. Verify that the configuration is no longer matched with the existing JUnit configuration because factoryName now participates in element identification. This demonstrates that merge:id="@@" uses all atributes of an element as merge identifiers.

---

Checklist for this PR

Make sure everything is checked before merging this PR. For further info please also see
our DoD.

• When running mvn clean test locally all tests pass and build is successful
• PR title is of the form #«issue-id»: «brief summary» (e.g. #921: fixed setup.bat and not feature/921 fixed setup.bat). If no issue ID exists, title only.
• PR top-level comment summaries what has been done and contains link to addressed issue(s)
• PR and issue(s) have suitable labels
• Issue is set to In Progress and assigned to you or there is no issue (might happen for very small PRs)
• You followed all coding conventions
• You have added the issue implemented by your PR in CHANGELOG.adoc unless issue is labelled
  with internal
• You have not changed any dependency in pom.xml files or otherwise if runtime dependencies changed, you have updated our LICENSE.asciidoc
• You have formulated clear instructions on how to test your contribution under "Testing instructions"

[coveralls]

Coverage Report for CI Build 34355148101

Coverage increased (+0.07%) to 73.975%

Details

• Coverage increased (+0.07%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 4 coverage regressions across 1 file.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

4 previously-covered lines in 1 file lost coverage.

File	Lines Losing Coverage	Coverage
com/devonfw/tools/ide/merge/xml/matcher/IdComputer.java	4	93.16%

---

Coverage Stats

Relevant Lines:	18828
Covered Lines:	14552
Line Coverage:	77.29%
Relevant Branches:	8419
Covered Branches:	5604
Branch Coverage:	66.56%
Branches in Coverage %:	Yes
Coverage Strength:	3.3 hits per line

---

💛 - Coveralls

[Khaled-Cap]

Implementation is clean. Tests are running successfully. The added functionality was tested locally and it works as described. PR will be moved to "in review"