fix(remote-config): resolve ui_config parts as blobs, not inline metadata

UiConfigProvider read each part (app, localizations, variable_config,
custom_variables) from the topic item's inline metadata. Production serves
every part as its own blob-ref item instead, so metadata was always empty and
getUiConfig() silently returned an all-defaults UiConfig regardless of what
the backend actually sent — confirmed against a real /v1/config response.

Switch to RemoteConfigManager.blobData(), which resolves the referenced blob
(fetching on demand and deduping against any in-flight prefetch) instead of
reading the item index directly. Updated UiConfigProviderTest's fixtures to
match — the previous inline-metadata fixtures exercised a shape production
never sends, which is exactly how this went unnoticed.

Author: vegaro

purchases/src/main/kotlin/com/revenuecat/purchases/common/remoteconfig/UiConfigProvider.kt

@@ -9,18 +9,20 @@ import kotlinx.serialization.json.decodeFromJsonElement
 /**
  * The topic-specific front door for `ui_config`: four independently-updated parts — `app`, `localizations`,
  * `variable_config`, `custom_variables` — that together deserialize as one [UiConfig], the same shape the legacy
- * offerings response sends pre-assembled in a single JSON object. Each part is inline item metadata (no blob), so
- * it's read straight off the topic's item index. A part with no body (topic absent or item absent) is simply
- * omitted, so [UiConfig]'s own field defaults fill the gap.
+ * offerings response sends pre-assembled in a single JSON object. Each part is its own blob-ref item under the
+ * topic (not inline metadata), resolved through [RemoteConfigManager.blobData]. A part with no resolvable blob
+ * (topic absent, item absent, or blob unresolvable) is simply omitted, so [UiConfig]'s own field defaults fill
+ * the gap.
  */
 @OptIn(InternalRevenueCatAPI::class)
 internal class UiConfigProvider(
     private val manager: RemoteConfigManager,
 ) {
 
     suspend fun getUiConfig(): UiConfig {
-        val topic = manager.topic(RemoteConfigTopic.UiConfig)
-        val parts = PART_KEYS.mapNotNull { key -> topic?.get(key)?.let { key to it.metadata } }.toMap()
+        val parts = PART_KEYS.mapNotNull { key ->
+            manager.blobData<JsonObject>(RemoteConfigTopic.UiConfig, key)?.let { key to it }
+        }.toMap()
         return JsonTools.json.decodeFromJsonElement(JsonObject(parts))
     }
 

purchases/src/test/java/com/revenuecat/purchases/common/remoteconfig/UiConfigProviderTest.kt

@@ -6,7 +6,6 @@ import com.revenuecat.purchases.paywalls.components.common.VariableLocalizationK
 import io.mockk.coEvery
 import io.mockk.mockk
 import kotlinx.coroutines.test.runTest
-import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.buildJsonObject
 import kotlinx.serialization.json.put
 import org.assertj.core.api.Assertions.assertThat
@@ -19,42 +18,30 @@ internal class UiConfigProviderTest {
     private val provider = UiConfigProvider(manager)
 
     @Test
-    fun `getUiConfig assembles all four topic parts into one UiConfig`() = runTest {
-        val topic = ConfigTopic(
-            mapOf(
-                "app" to RemoteConfiguration.ConfigItem(
-                    metadata = buildJsonObject {
-                        put("colors", buildJsonObject {})
-                        put("fonts", buildJsonObject {})
-                    },
-                ),
-                "localizations" to RemoteConfiguration.ConfigItem(
-                    metadata = buildJsonObject {
-                        put("en_US", buildJsonObject { put("day", "Day") })
-                    },
-                ),
-                "variable_config" to RemoteConfiguration.ConfigItem(
-                    metadata = buildJsonObject {
-                        put("variable_compatibility_map", buildJsonObject { put("old_var", "new_var") })
-                        put("function_compatibility_map", buildJsonObject {})
-                    },
-                ),
-                // The part this test exists to guard: dropped from PART_KEYS in an earlier revision, which
-                // silently discarded custom_variables from every ui_config read.
-                "custom_variables" to RemoteConfiguration.ConfigItem(
-                    metadata = buildJsonObject {
-                        put(
-                            "user_name",
-                            buildJsonObject {
-                                put("type", "string")
-                                put("default_value", "Friend")
-                            },
-                        )
-                    },
-                ),
-            ),
-        )
-        coEvery { manager.topic(RemoteConfigTopic.UiConfig) } returns topic
+    fun `getUiConfig assembles all four blob-ref parts into one UiConfig`() = runTest {
+        // Production serves every ui_config part (app, localizations, variable_config, custom_variables) as
+        // its own blob-ref item under the topic — never as inline item metadata. An earlier revision read
+        // item.metadata directly, which silently produced an all-defaults UiConfig against real backend data.
+        stubBlob("app") {
+            put("colors", buildJsonObject {})
+            put("fonts", buildJsonObject {})
+        }
+        stubBlob("localizations") {
+            put("en_US", buildJsonObject { put("day", "Day") })
+        }
+        stubBlob("variable_config") {
+            put("variable_compatibility_map", buildJsonObject { put("old_var", "new_var") })
+            put("function_compatibility_map", buildJsonObject {})
+        }
+        stubBlob("custom_variables") {
+            put(
+                "user_name",
+                buildJsonObject {
+                    put("type", "string")
+                    put("default_value", "Friend")
+                },
+            )
+        }
 
         val uiConfig = provider.getUiConfig()
 
@@ -67,25 +54,37 @@ internal class UiConfigProviderTest {
     }
 
     @Test
-    fun `getUiConfig defaults every field when the ui_config topic is absent`() = runTest {
-        coEvery { manager.topic(RemoteConfigTopic.UiConfig) } returns null
+    fun `getUiConfig defaults every field when no part's blob resolves`() = runTest {
+        coEvery {
+            manager.blobData<Any>(RemoteConfigTopic.UiConfig, any(), any())
+        } returns null
 
         val uiConfig = provider.getUiConfig()
 
         assertThat(uiConfig).isEqualTo(com.revenuecat.purchases.UiConfig())
     }
 
     @Test
-    fun `getUiConfig defaults custom_variables to empty when its topic item is absent`() = runTest {
-        val topic = ConfigTopic(
-            mapOf(
-                "app" to RemoteConfiguration.ConfigItem(metadata = JsonObject(emptyMap())),
-            ),
-        )
-        coEvery { manager.topic(RemoteConfigTopic.UiConfig) } returns topic
+    fun `getUiConfig defaults custom_variables to empty when only its blob is unresolved`() = runTest {
+        stubBlob("app") {}
+        coEvery {
+            manager.blobData<Any>(RemoteConfigTopic.UiConfig, "custom_variables", any())
+        } returns null
+        coEvery {
+            manager.blobData<Any>(RemoteConfigTopic.UiConfig, "localizations", any())
+        } returns null
+        coEvery {
+            manager.blobData<Any>(RemoteConfigTopic.UiConfig, "variable_config", any())
+        } returns null
 
         val uiConfig = provider.getUiConfig()
 
         assertThat(uiConfig.customVariables).isEmpty()
     }
+
+    private fun stubBlob(key: String, content: kotlinx.serialization.json.JsonObjectBuilder.() -> Unit) {
+        coEvery {
+            manager.blobData<Any>(RemoteConfigTopic.UiConfig, key, any())
+        } returns buildJsonObject(content)
+    }
 }