From dc46e522af6fcf05a376770b982fb457d2df08c8 Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoit@matrix.org>
Date: Wed, 22 Oct 2025 15:28:31 +0200
Subject: [PATCH] Improve API of interface WellknownRetriever to be able to
 distinguish between 404 and other errors.

---
 .../libraries/matrix/impl/RustMatrixClient.kt |  2 +-
 .../impl/DefaultSessionWellknownRetriever.kt  | 42 +++++++++----------
 2 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClient.kt b/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClient.kt
index c646e2ee18..94a562c160 100644
--- a/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClient.kt
+++ b/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClient.kt
@@ -286,7 +286,7 @@ class RustMatrixClient(
     override suspend fun getUrl(url: String): Result<ByteArray> = withContext(sessionDispatcher) {
         runCatchingExceptions {
             innerClient.getUrl(url)
-        }
+        }.mapFailure { it.mapClientException() }
     }
 
     override suspend fun getRoom(roomId: RoomId): BaseRoom? = withContext(sessionDispatcher) {
diff --git a/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt
index 1c7e28e62c..81b4d99134 100644
--- a/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt
+++ b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt
@@ -13,6 +13,7 @@ import io.element.android.libraries.androidutils.json.JsonProvider
 import io.element.android.libraries.core.extensions.mapCatchingExceptions
 import io.element.android.libraries.di.SessionScope
 import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.exception.ClientException
 import io.element.android.libraries.wellknown.api.ElementWellKnown
 import io.element.android.libraries.wellknown.api.SessionWellknownRetriever
 import io.element.android.libraries.wellknown.api.WellKnown
@@ -33,18 +34,9 @@ class DefaultSessionWellknownRetriever(
             .getUrl(url)
             .mapCatchingExceptions {
                 val data = String(it)
-                json().decodeFromString(InternalWellKnown.serializer(), data)
+                json().decodeFromString<InternalWellKnown>(data).map()
             }
-            .onFailure { Timber.e(it, "Failed to retrieve .well-known from $domain") }
-            .map { it.map() }
-            .fold(
-                onSuccess = {
-                    WellknownRetrieverResult.Success(it)
-                },
-                onFailure = {
-                    WellknownRetrieverResult.Error(it as Exception)
-                }
-            )
+            .toWellknownRetrieverResult()
     }
 
     override suspend fun getElementWellKnown(): WellknownRetrieverResult<ElementWellKnown> {
@@ -53,17 +45,23 @@ class DefaultSessionWellknownRetriever(
             .getUrl(url)
             .mapCatchingExceptions {
                 val data = String(it)
-                json().decodeFromString(InternalElementWellKnown.serializer(), data)
+                json().decodeFromString<InternalElementWellKnown>(data).map()
             }
-            .onFailure { Timber.e(it, "Failed to retrieve Element .well-known from $domain") }
-            .map { it.map() }
-            .fold(
-                onSuccess = {
-                    WellknownRetrieverResult.Success(it)
-                },
-                onFailure = {
-                    WellknownRetrieverResult.Error(it as Exception)
-                }
-            )
+            .toWellknownRetrieverResult()
     }
+
+    private fun <T> Result<T>.toWellknownRetrieverResult(): WellknownRetrieverResult<T> = fold(
+        onSuccess = {
+            WellknownRetrieverResult.Success(it)
+        },
+        onFailure = {
+            Timber.e(it, "Failed to retrieve Element .well-known from $domain")
+            // This check on message value is not ideal but this is what we got from the SDK.
+            if ((it as? ClientException.Generic)?.message?.contains("404") == true) {
+                WellknownRetrieverResult.NotFound
+            } else {
+                WellknownRetrieverResult.Error(it as Exception)
+            }
+        }
+    )
 }