Remove jacoco append property

[vpbhargav]

#5428 - Issue this PR solves

Gradle was warning about deprecated feature usage. Logs show jacoco append to be the feature that is deprecated.From my understandind the propery is currently ignored.

Removed the Jacoco append property from build.gradle and builds don't throw any deprecation warnings anymore.

The append property in Jacoco is meant to write to the same coverage file. But as mentioned in this issue setting it to true broke the build caching capability. So starting Gradle 5.0 a breaking change was introduced where they did away with the append property. The default behavior was set to behave as if append is initially false to enable build caching and then append is set to true before passing to the jacoco agent.
This meant that multiple tasks could not use the same coverage file but Jacoco merge is a feature that let's you achieve the same functionality. The gradle for the project does use Jacoco Merge to merge the various .exec file results, so removing the append property should not break coverage.

---

• Change in CHANGELOG.md described
• Tests created for changes
• Manually tested changed features in running JabRef
• Screenshots added in PR description (for bigger UI changes)
• Ensured that the git commit message is a good one
• Check documentation status (Issue created for outdated help page at help.jabref.org?)

[koppor]

Could you write something about what the append feature was meant for? What behavior is changed when the property is removed?

[vpbhargav]

@koppor, added explanation and references.

[tobiasdiez]

Thanks for the explanation. I'd say we merge now and see if the code coverage stays constant. (For some reason the coverage is not calculated for PRs...@koppor do you know why?)

[koppor]

@tobiasdiez I have no clue...

[vpbhargav]

@tobiasdiez - I wanted to check codecov for the same and noticed it doesn't show for PRs. But even for the master branch the last update in codecov is 2 months back? Does that mean it is not picking up changes?

Edit :
The last tracked job in codecov seemed to have picked up reports in Travis build log. So looks like reports are not being generated for a while now?

Dug further into the build logs and "Task :jacocoMerge FAILED". Will see how far back this is the case and see what is causing it to fail.

[koppor]

@vpbhargav Any updates on the report generation? We switched to GitHub workflows - so you could check there?

[LyzardKing]

@koppor The tests are still running on travis at the moment
The jacoco test fails with this error:

Execution failed for task ':jacocoMerge'.
> Unable to read /home/travis/build/JabRef/jabref/build/jacoco/databaseTest.exec

[vpbhargav]

@koppor , I only got to the point @LyzardKing has mentioned. But the Database tests seemed to pass. So was not sure what was going wrong. Will start looking at this again and probably try to fix it over the weekend. Sorry for not keeping you posted.

[Siedlerchr]

The database test are currently broken (not executed) as I noticed it in #5394

[LyzardKing]

@Siedlerchr
In the log from your PR could this be the issue?
14:57:17.299 [Test worker] ERROR org.jabref.logic.shared.DBMSConnection - Could not connect to database: No suitable driver found for jdbc:oracle:thin:@localhost:1521:xe - Error code: 0

[Siedlerchr]

That's just one problem,. The unit tests are parameterized tests, each test is executed for each database system (MySQL, Postgres and oracle). The missing oracle driver is another PR.
The real problem is somehow the sync between the bib and the shared db