Add Attest Build Provenance step

Addresses part of #3128

---------

Co-authored-by: Marc Philipp <mail@marcphilipp.de>

.github/workflows/main.yml

@@ -41,7 +41,8 @@ jobs:
           -Ptesting.enableJaCoCo \
           build \
           jacocoRootReport \
-          prepareDocsForUploadToGhPages
+          prepareDocsForUploadToGhPages \
+          prepareGitHubAttestation
     - name: Upload to Codecov.io
       uses: codecov/codecov-action@v4
       with:
@@ -71,6 +72,9 @@ jobs:
     name: Publish Snapshot Artifacts
     needs: linux
     runs-on: ubuntu-latest
+    permissions:
+      attestations: write # required for build provenance attestation
+      id-token: write # required for build provenance attestation
     if: github.event_name == 'push' && github.repository == 'junit-team/junit5' && (startsWith(github.ref, 'refs/heads/releases/') || github.ref == 'refs/heads/main')
     steps:
     - name: Check out repository
@@ -84,6 +88,10 @@ jobs:
         ORG_GRADLE_PROJECT_sonatypePassword: ${{ secrets.SONATYPE_PASSWORD }}
       with:
         arguments: publish -x check
+    - name: Generate build provenance attestations
+      uses: actions/attest-build-provenance@49df96e17e918a15956db358890b08e61c704919 # v1.2.0
+      with:
+        subject-path: documentation/build/attestation/*.jar
 
   update_documentation:
     name: Update Snapshot Documentation

documentation/documentation.gradle.kts

@@ -17,6 +17,7 @@ plugins {
 	id("junitbuild.testing-conventions")
 }
 
+val mavenizedProjects: List<Project> by rootProject
 val modularProjects: List<Project> by rootProject
 
 // Because we need to set up Javadoc aggregation
@@ -35,6 +36,11 @@ val standaloneConsoleLauncher = configurations.dependencyScope("standaloneConsol
 val standaloneConsoleLauncherClasspath = configurations.resolvable("standaloneConsoleLauncherClasspath") {
 	extendsFrom(standaloneConsoleLauncher.get())
 }
+val attestation = configurations.dependencyScope("attestation")
+val attestationClasspath = configurations.resolvable("attestationClasspath") {
+	extendsFrom(attestation.get())
+	isTransitive = false
+}
 
 val tools by sourceSets.creating
 val toolsImplementation by configurations.getting
@@ -48,6 +54,10 @@ dependencies {
 	// in reports generated by the ApiReportGenerator.
 	modularProjects.forEach { apiReport(it) }
 
+	// Pull in all "mavenized projects" to ensure that they are included
+	// in the generation of build provenance attestation.
+	mavenizedProjects.forEach { attestation(it) }
+
 	testImplementation(projects.junitJupiterMigrationsupport)
 	testImplementation(projects.junitPlatformConsole)
 	testImplementation(projects.junitPlatformRunner)
@@ -502,6 +512,11 @@ tasks {
 	gitPublishCommit {
 		dependsOn(configureGitAuthor)
 	}
+
+	val prepareGitHubAttestation by registering(Sync::class) {
+		from(attestationClasspath)
+		into(layout.buildDirectory.dir("attestation"))
+	}
 }
 
 eclipse {