feat(gradle-plugin): default release mode to event

.changeset/gradle-plugin-event-release-mode-default.md

@@ -0,0 +1,9 @@
+---
+'posthog-android-gradle-plugin': minor
+---
+
+Default `posthog.releaseMode` to `event`. The proguard mapping now uploads release-independent. Each event resolves its own release from the `$app_namespace` / `$app_version` / `$app_build` the SDK already sends. Two releases that ship the same mapping no longer both report whichever release uploaded it first.
+
+Set `posthog.releaseMode=symbol-set`, or `POSTHOG_RELEASE_MODE=symbol-set`, to keep stamping the release onto the uploaded mapping.
+
+Event mode needs posthog-cli 0.13.0 or newer. That version added `--release-mode` to `proguard upload`. The release coordinates the build sends must match the app's applicationId, versionName and versionCode.

posthog-android-gradle-plugin/src/main/kotlin/com/posthog/android/PostHogUploadProguardMappingsTask.kt

@@ -105,8 +105,9 @@ public abstract class PostHogUploadProguardMappingsTask : PostHogCliExecTask() {
             args.add("--build")
             args.add(it.toString())
         }
-        // Passed only outside the default mode, so a symbol-set build keeps working against a
-        // posthog-cli predating the flag.
+        // Passed only outside symbol-set mode, so a symbol-set build keeps working against a
+        // posthog-cli predating the flag. The environment variable set above pins the mode for
+        // binaries that do know it.
         releaseMode.orNull?.takeIf { it != PostHogReleaseMode.SYMBOL_SET.cliValue }?.let {
             args.add("--release-mode")
             args.add(it)
@@ -122,7 +123,7 @@ public abstract class PostHogUploadProguardMappingsTask : PostHogCliExecTask() {
             releaseName: Provider<String>? = null,
             releaseVersion: Provider<String>? = null,
             build: Provider<Int>? = null,
-            releaseMode: PostHogReleaseMode = PostHogReleaseMode.SYMBOL_SET,
+            releaseMode: PostHogReleaseMode = PostHogReleaseMode.EVENT,
         ): TaskProvider<PostHogUploadProguardMappingsTask> {
             val uploadPostHogProguardMappingsTask =
                 project.tasks.register(

posthog-android-gradle-plugin/src/main/kotlin/com/posthog/android/Utils.kt

@@ -145,7 +145,7 @@ internal enum class PostHogReleaseMode(val cliValue: String) {
 /**
  * Release mode for this build: the `posthog.releaseMode` gradle property, then the
  * `POSTHOG_RELEASE_MODE` environment variable posthog-cli and the bundler plugins already read,
- * then [PostHogReleaseMode.SYMBOL_SET].
+ * then [PostHogReleaseMode.EVENT].
  *
  * An unrecognized value fails the build rather than falling back, so a typo can't silently leave
  * a build binding its mapping to a release it meant to keep independent.
@@ -157,7 +157,7 @@ internal fun resolvePostHogReleaseMode(
     val value =
         project.findProperty(POSTHOG_RELEASE_MODE_PROPERTY)?.toString()?.trim()?.takeIf { it.isNotEmpty() }
             ?: environment[POSTHOG_RELEASE_MODE_ENV]?.trim()?.takeIf { it.isNotEmpty() }
-            ?: return PostHogReleaseMode.SYMBOL_SET
+            ?: return PostHogReleaseMode.EVENT
 
     return PostHogReleaseMode.from(value)
         ?: error(

posthog-android-gradle-plugin/src/test/java/com/posthog/android/PostHogReleaseModeTest.kt

@@ -0,0 +1,55 @@
+package com.posthog.android
+
+import org.gradle.api.Project
+import org.gradle.testfixtures.ProjectBuilder
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+
+internal class PostHogReleaseModeTest {
+    // Not `apply`: Project has its own apply(), so the scope function would resolve to Gradle's.
+    private fun project(releaseMode: String? = null): Project {
+        val project = ProjectBuilder.builder().build()
+        releaseMode?.let { project.extensions.extraProperties.set(POSTHOG_RELEASE_MODE_PROPERTY, it) }
+        return project
+    }
+
+    @Test
+    fun `a build that configures nothing uploads its mapping release-independent`() {
+        assertEquals(PostHogReleaseMode.EVENT, resolvePostHogReleaseMode(project(), emptyMap()))
+    }
+
+    @Test
+    fun `the gradle property selects the mode`() {
+        assertEquals(
+            PostHogReleaseMode.SYMBOL_SET,
+            resolvePostHogReleaseMode(project(releaseMode = "symbol-set"), emptyMap()),
+        )
+    }
+
+    @Test
+    fun `the environment variable selects the mode`() {
+        assertEquals(
+            PostHogReleaseMode.SYMBOL_SET,
+            resolvePostHogReleaseMode(project(), mapOf(POSTHOG_RELEASE_MODE_ENV to "symbol-set")),
+        )
+    }
+
+    @Test
+    fun `the gradle property wins over the environment variable`() {
+        assertEquals(
+            PostHogReleaseMode.SYMBOL_SET,
+            resolvePostHogReleaseMode(
+                project(releaseMode = "symbol-set"),
+                mapOf(POSTHOG_RELEASE_MODE_ENV to "event"),
+            ),
+        )
+    }
+
+    @Test
+    fun `an unrecognized value fails the build instead of picking a mode`() {
+        assertFailsWith<IllegalStateException> {
+            resolvePostHogReleaseMode(project(releaseMode = "symbolset"), emptyMap())
+        }
+    }
+}