fix: warn about empty and personal API keys without debug and log rejected batches

.changeset/android-v4-major.md

@@ -20,7 +20,7 @@
 - **Breaking:** rename `PostHogConfig.maxRetries` to `pushNotificationSubscriptionMaxRetries`, because it only limits push-notification subscription retries
 - **Breaking:** set `$lib` and `$lib_version` from the `PostHog-Sdk-Info` request header; a value set in properties, super properties or `beforeSend` is removed before sending
 - **Breaking:** send `$session_id` and `$window_id` as top-level `session_id` and `window_id` fields; a non-string value is dropped with a warning
-- **Breaking:** disable the SDK at setup when `projectToken` is a personal API key (`phx_...`), as for an empty token
+- **Breaking:** disable the SDK at setup when `projectToken` is a personal API key (`phx_...`), as for an empty token, and print a warning for both even when `debug` is off
 - **Breaking:** add an `options` argument to `capture`, `screen`, `identify`, `setPersonProperties`, `alias`, `group` and `captureException` for per-event capture options such as `cookieless_mode`, sent apart from the properties and editable in `beforeSend` through `PostHogEvent.options`; Java callers pass the trailing argument or `null`, and classes that implement `PostHogInterface` add the parameter
 - **Breaking:** move `identify(distinctId, userProperties, userPropertiesSetOnce)` from `PostHogCoreInterface` to `PostHogStatelessInterface`; `PostHogInterface` declares `identify` with the trailing `options` parameter
 - **Breaking:** registered super properties now override the properties the SDK sets itself, such as `$os_name`; super and event properties also override `$is_identified`, `$process_person_profile` and the session replay debug properties, which the SDK no longer re-applies after the caller's values
@@ -30,7 +30,7 @@
 - use the current distinct ID when the `distinctId` argument to `capture` is empty or whitespace-only, instead of dropping the event
 - **Breaking:** skip deep link query parameters whose name starts with `$` in the `Deep Link Opened` event, so a link can't set a PostHog property such as `$process_person_profile`
 - stop storing or matching the person-properties deduplication hash for a `$set` sent with `process_person_profile: false`
-- debug logs for capture requests name the event count and the response status instead of printing the request and response bodies, and count the events PostHog drops, the duplicate copies it drops and the events it asks to retry, in one line per batch
+- debug logs for capture requests name the event count and the response status instead of printing the request and response bodies, and count the events PostHog drops, the duplicate copies it drops and the events it asks to retry, in one line per batch, and log the status when PostHog rejects a whole batch
 - **Breaking:** drop an event whose name is empty before sending it, including one `beforeSend` renames to `""`
 - **Breaking:** let `userProperties`, `userPropertiesSetOnce` and `groups` win key by key over `$set`, `$set_once` and `$groups` maps passed in the same call's properties, instead of being replaced by them, and merge a `$groups` map in properties into the groups set with `group()`
 - add `captureAiCompression`, `captureAiMaxQueueSize`, `captureAiTimeout` and `captureAiMaxEventBytes` to `PostHogConfig` to tune AI requests separately from other events; the defaults are gzip, 100 queued events (and at most 50 MiB), 60 seconds and 8 MiB + 64 KiB per serialized event

posthog/src/main/java/com/posthog/PostHog.kt

@@ -223,14 +223,14 @@ public class PostHog private constructor(
                     if (config.logger is PostHogNoOpLogger) PostHogPrintLogger(config) else config.logger
 
                 if (config.projectToken.isEmpty()) {
-                    config.logger.log(
+                    config.logger.logWarning(
                         "PostHog SDK is disabled because the project token is required and was empty after trimming whitespace.",
                     )
                     return
                 }
 
                 if (config.projectToken.startsWith("phx_")) {
-                    config.logger.log(
+                    config.logger.logWarning(
                         "PostHog SDK is disabled because the project token is a personal API key (phx_...), " +
                             "use your project token (phc_...).",
                     )

posthog/src/main/java/com/posthog/PostHogStateless.kt

@@ -62,14 +62,14 @@ public open class PostHogStateless protected constructor(
                     if (config.logger is PostHogNoOpLogger) PostHogPrintLogger(config) else config.logger
 
                 if (config.projectToken.isEmpty()) {
-                    config.logger.log(
+                    config.logger.logWarning(
                         "PostHog SDK is disabled because the project token is required and was empty after trimming whitespace.",
                     )
                     return
                 }
 
                 if (config.projectToken.startsWith("phx_")) {
-                    config.logger.log(
+                    config.logger.logWarning(
                         "PostHog SDK is disabled because the project token is a personal API key (phx_...), " +
                             "use your project token (phc_...).",
                     )

posthog/src/main/java/com/posthog/internal/PostHogQueue.kt

@@ -751,5 +751,6 @@ internal fun deleteFilesIfAPIError(
 
         return false
     }
+    logger.log("Flushing failed with ${e.statusCode}, dropping $actualBatchSize records.")
     return true
 }

posthog/src/test/java/com/posthog/PostHogStatelessTest.kt

@@ -277,7 +277,7 @@ internal class PostHogStatelessTest {
         sut.setup(config)
 
         assertFalse(sut.isEnabledPublic())
-        assertTrue(mockLogger.messages.any { it.contains("PostHog SDK is disabled because the project token is required") })
+        assertTrue(mockLogger.warnings.any { it.contains("PostHog SDK is disabled because the project token is required") })
     }
 
     @Test
@@ -289,7 +289,7 @@ internal class PostHogStatelessTest {
         sut.setup(config)
 
         assertFalse(sut.isEnabledPublic())
-        assertTrue(mockLogger.messages.any { it.contains("PostHog SDK is disabled because the project token is a personal API key") })
+        assertTrue(mockLogger.warnings.any { it.contains("PostHog SDK is disabled because the project token is a personal API key") })
     }
 
     @Test

posthog/src/test/java/com/posthog/PostHogTest.kt

@@ -276,7 +276,7 @@ internal class PostHogTest {
             )
 
         assertTrue(sut.isOptOut())
-        assertTrue(logger.messages.any { it.contains("PostHog SDK is disabled because the project token is required") })
+        assertTrue(logger.warnings.any { it.contains("PostHog SDK is disabled because the project token is required") })
 
         sut.close()
     }
@@ -297,7 +297,7 @@ internal class PostHogTest {
             )
 
         assertTrue(sut.isOptOut())
-        assertTrue(logger.messages.any { it.contains("PostHog SDK is disabled because the project token is a personal API key") })
+        assertTrue(logger.warnings.any { it.contains("PostHog SDK is disabled because the project token is a personal API key") })
 
         sut.close()
     }

posthog/src/test/java/com/posthog/internal/PostHogQueueTest.kt

@@ -5,6 +5,7 @@ import com.posthog.PostHogConfig
 import com.posthog.PostHogEvent
 import com.posthog.PostHogEventName
 import com.posthog.TestHttpServers
+import com.posthog.TestLogger
 import com.posthog.awaitExecution
 import com.posthog.generateEvent
 import com.posthog.internal.errortracking.ThrowableCoercer
@@ -958,8 +959,10 @@ internal class PostHogQueueTest {
         val e = PostHogApiError(400, "", null)
         val config = PostHogConfig(PROJECT_TOKEN)
         val limits = initialBatchLimits(config)
+        val logger = TestLogger()
 
-        assertTrue(deleteFilesIfAPIError(e, limits, actualBatchSize = limits.cap, logger = config.logger))
+        assertTrue(deleteFilesIfAPIError(e, limits, actualBatchSize = limits.cap, logger = logger))
+        assertEquals(listOf("Flushing failed with 400, dropping ${limits.cap} records."), logger.messages)
     }
 
     @Test