fix: convert a JSON null to null, not to the text "null"

CHANGELOG.md

@@ -5,6 +5,7 @@ The changelog for `Superwall`. Also see the [releases](https://github.com/superw
 ## Unreleased
 
 - Fix prices not showing when product/offers are fetched from cache
+- Fix a JSON null in placement parameters or user attributes reaching audience filters as the text `"null"`, so a filter checking whether a field is null never matched.
 
 ## 2.8.2
 

superwall/src/main/java/com/superwall/sdk/paywall/presentation/rule_logic/cel/SuperscriptEvaluator.kt

@@ -27,6 +27,7 @@ import kotlinx.serialization.encodeToString
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonArray
 import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonNull
 import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.JsonPrimitive
 import kotlinx.serialization.json.boolean
@@ -246,6 +247,11 @@ internal fun Any.toPassableValue(): PassableValue =
 
 private fun JsonElement.toPassableValue(): PassableValue =
     when (this) {
+        // Checked before JsonPrimitive, which JsonNull is a kind of. Without this a
+        // JSON null falls past every primitive branch and comes out as the string
+        // "null", so an audience filter comparing the field to null never matches.
+        is JsonNull -> PassableValue.NullValue
+
         is JsonObject ->
             PassableValue.MapValue(
                 this.mapValues { (_, value) -> value.toPassableValue() }.toMap(),

superwall/src/test/java/com/superwall/sdk/paywall/presentation/rule_logic/JsonElementToPassableValueTest.kt

@@ -64,6 +64,14 @@ class JsonElementToPassableValueTest {
         assertEquals(false, (passableFalseValue as PassableValue.BoolValue).value)
     }
 
+    @Test
+    fun `test JsonNull conversion to PassableValue`() {
+        // JsonNull is a JsonPrimitive, so without an explicit branch it falls past
+        // every primitive check and comes out as the string "null". An audience
+        // filter asking `field == null` would then never match.
+        assertTrue(JsonNull.toPassableValue() is PassableValue.NullValue)
+    }
+
     @Test
     fun `test JsonObject conversion to PassableValue`() {
         val jsonObject =
@@ -94,8 +102,7 @@ class JsonElementToPassableValueTest {
         assertTrue(resultMap["boolean"] is PassableValue.BoolValue)
         assertEquals(true, (resultMap["boolean"] as PassableValue.BoolValue).value)
 
-        assertTrue(resultMap["null"] is PassableValue.StringValue)
-        assertEquals("null", (resultMap["null"] as PassableValue.StringValue).value)
+        assertTrue(resultMap["null"] is PassableValue.NullValue)
     }
 
     @Test
@@ -128,8 +135,7 @@ class JsonElementToPassableValueTest {
         assertTrue(resultList[3] is PassableValue.BoolValue)
         assertEquals(true, (resultList[3] as PassableValue.BoolValue).value)
 
-        assertTrue(resultList[4] is PassableValue.StringValue)
-        assertEquals("null", (resultList[4] as PassableValue.StringValue).value)
+        assertTrue(resultList[4] is PassableValue.NullValue)
     }
 
     @Test