sonarqube: quality gate failed on new code coverage below 80 percent

TL;DR

Find the uncovered new lines in the SonarQube pull request view, add tests that exercise them (both sides of new conditionals), and re-run analysis. Deliberately exclude generated code via the sonar.coverage.exclusions property rather than gaming the number. The gate counts only lines added in the PR, so a small untested change can fail an otherwise well-tested repo.

The error

sonarqube: quality gate failed on new code coverage below 80 percent

Steps to fix

1. Open the SonarQube project, go to the pull request or branch, and open the Coverage on New Code measure to list files with uncovered new lines.

• Expected: a short list of files, each with specific uncovered lines highlighted.

1. For each file, open the source view and write tests covering the new branches - both the true and false sides of new conditionals, not just the happy path.

• Expected: the new tests fail before the fix only if the code is wrong; here they just need to execute the lines.

1. If some new code is generated or genuinely untestable, add it to coverage exclusions deliberately through the sonar.coverage.exclusions property.

• Expected: generated files stop counting against the metric.

1. Push and re-run the scanner.

• Expected: the quality gate passes with new-code coverage at or above 80 percent.

Use this when

• The SonarQube quality gate fails specifically on the new-code coverage condition.
• A PR adds untested lines to a repo that is otherwise well covered.
• You want the gate green without weakening it.

Not for this skill when

• The gate fails on bugs, vulnerabilities, or duplications rather than coverage (different conditions, different fixes).
• Coverage shows 0 percent because the report was never uploaded (fix the report path first).
• The team has decided the threshold itself is wrong (that's a gate config change, not a coverage fix).

Variant phrasings

• sonarqube quality gate coverage on new code failed
• PR blocked sonar coverage below 80 percent
• new code coverage gate red sonarqube
• sonarqube pull request coverage check failing

Why it happens

SonarQube's default quality gate requires 80 percent coverage on new code. Coverage is measured per PR diff, so years of legacy coverage don't help - only the lines you touched count. A PR that adds a 20-line untested helper to a fully covered repo lands around 0 percent new-code coverage and fails the gate on its own.

Edge cases

• Coverage shows 0 because the scanner ran before tests produced the report, or the report path is misconfigured - check the scanner logs for the report import.
• Monorepos with several coverage files need them merged before analysis, or only one module's coverage counts.
• Tiny PRs (a handful of lines) swing the percentage wildly - one uncovered line can mean 75 percent; that's the metric working as designed.
• Excluding files to hit the number without reason just hides risk; exclude only generated or truly untestable code.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_xTOkTE05sN0EMsdHT4t0rw