build(coverage): finish wiring JaCoCo unit-test coverage reporting

Completes the crash-interrupted #192 WIP (app/build.gradle.kts already had a
jacocoTestReport task and toolVersion pin recovered onto build-192-jacoco):

- Move the JaCoCo tool version into gradle/libs.versions.toml instead of a
  hardcoded string in app/build.gradle.kts, matching how every other plugin
  version in this repo is sourced.
- Fix the generated-code exclusion list against the real compileDebugKotlin
  output (verified by inspecting the compiled class tree): Room's
  KSP-generated `_Impl` DAOs/database and the Compose compiler's per-file
  ComposableSingletons holders are the only generated code that actually
  lands in classDirectories, since Hilt/Dagger's generated Java and AGP's
  BuildConfig/R/Manifest are compiled by a separate javac task this report
  never reads. Drop the blanket `**/*$$*` exclude the WIP had — it was
  silently discarding ~200 real classes' worth of coverage on Kotlin's own
  `$$inlined$` synthetic classes (e.g. Flow.map { ... } transforms in the
  repositories), which is hand-written logic, not generated boilerplate.
- Add Hilt_*/Dagger* prefix patterns so the (currently inert,
  belt-and-suspenders) Hilt exclusions are actually correct if the
  classDirectories scope ever changes.
- Add a minimal CI step to the existing unit-tests job that runs
  jacocoTestReport and uploads the XML+HTML report as a build artifact.
  No coverage threshold gate yet (a jacocoTestCoverageVerification rule is
  a natural follow-up once there's a baseline).
- Document the new :app:jacocoTestReport task in CLAUDE.md.

Verified on JDK 21: fast gate (assembleDebug, testDebugUnitTest,
compileDebugAndroidTestKotlin, lintDebug, ktlintCheck, detekt) plus
jacocoTestReport all pass, from both a warm and a `clean` build. The
report shows real signal (30% instruction / 38% line coverage) with no
generated classes leaking in.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

This commit is contained in:

JMR-dev

2026-07-03 12:23:40 -05:00

co-authored by

Claude Opus 4.8

parent 05dde9399c

commit 535cbcb49a

4 changed files with 41 additions and 7 deletions

									
										gradle/libs.versions.toml
									
		+3
		
												View File
												
				@@ -35,6 +35,9 @@ errorprone = "2.50.0"

				# detekt 2.0 is the only line with Gradle 9 support (stable 1.23.x tops out at Gradle 8.12).

				ktlint = "14.2.0"

				detekt = "2.0.0-alpha.5"

				# JaCoCo coverage agent/report tool (issue #192). Pinned above Gradle's bundled default so the

				# coverage agent understands Kotlin 2.4.0 bytecode on JDK 21.

				jacoco = "0.8.13"

				[libraries]

				# AndroidX core / lifecycle / activity / navigation