ci: Publish snapshot builds to Maven Central on push to main

Add a `mavenCentralSnapshots` repository to both plugin-build and
sentry-kotlin-compiler-plugin build files, and a new GitHub Actions
workflow that publishes `-SNAPSHOT` versions on every push to main.

This gives consumers early access to unreleased changes without
waiting for a formal release. The snapshot flow is completely
independent from the existing craft-based release process.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: runningcode

.github/workflows/publish-snapshot.yml

@@ -0,0 +1,51 @@
+name: Publish Snapshot
+
+on:
+  push:
+    branches:
+      - main
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  publish-snapshot:
+    name: Publish snapshot to Maven Central
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@0723195856401067f7a2779048b490ace7a47d7c # pin@v4
+
+      - name: Set up Java
+        uses: actions/setup-java@v5
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+
+      - name: Determine snapshot version
+        id: version
+        run: |
+          VERSION=$(grep "^version = " plugin-build/gradle.properties | cut -d' ' -f3)
+          echo "snapshot_version=${VERSION}-SNAPSHOT" >> "$GITHUB_OUTPUT"
+
+      - name: Publish Gradle Plugin snapshot
+        working-directory: plugin-build
+        run: >
+          ../gradlew publishAllPublicationsToMavenCentralSnapshotsRepository
+          -Pversion=${{ steps.version.outputs.snapshot_version }}
+        env:
+          ORG_GRADLE_PROJECT_mavenCentralUsername: ${{ secrets.OSSRH_USERNAME }}
+          ORG_GRADLE_PROJECT_mavenCentralPassword: ${{ secrets.OSSRH_PASSWORD }}
+
+      - name: Publish Kotlin Compiler Plugin snapshot
+        working-directory: sentry-kotlin-compiler-plugin
+        run: >
+          ../gradlew publishAllPublicationsToMavenCentralSnapshotsRepository
+          -PVERSION_NAME=${{ steps.version.outputs.snapshot_version }}
+        env:
+          ORG_GRADLE_PROJECT_mavenCentralUsername: ${{ secrets.OSSRH_USERNAME }}
+          ORG_GRADLE_PROJECT_mavenCentralPassword: ${{ secrets.OSSRH_PASSWORD }}

plugin-build/build.gradle.kts

@@ -308,3 +308,18 @@ tasks.withType<ValidatePlugins>().configureEach {
   failOnWarning.set(true)
   enableStricterValidation.set(true)
 }
+
+plugins.withId("com.vanniktech.maven.publish.base") {
+  configure<PublishingExtension> {
+    repositories {
+      maven {
+        name = "mavenCentralSnapshots"
+        url = uri("https://central.sonatype.com/repository/maven-snapshots/")
+        credentials {
+          username = findProperty("mavenCentralUsername")?.toString()
+          password = findProperty("mavenCentralPassword")?.toString()
+        }
+      }
+    }
+  }
+}

sentry-kotlin-compiler-plugin/build.gradle.kts

@@ -73,6 +73,14 @@ plugins.withId("com.vanniktech.maven.publish.base") {
         name = "mavenTestRepo"
         url = file("${rootProject.projectDir}/../build/mavenTestRepo").toURI()
       }
+      maven {
+        name = "mavenCentralSnapshots"
+        url = uri("https://central.sonatype.com/repository/maven-snapshots/")
+        credentials {
+          username = findProperty("mavenCentralUsername")?.toString()
+          password = findProperty("mavenCentralPassword")?.toString()
+        }
+      }
     }
   }
 }