From a4aff0f76ddd147495c09f7d1dc9c2837ba7a3b0 Mon Sep 17 00:00:00 2001
From: Davis Wolfermann <offrange.developer@gmail.com>
Date: Tue, 29 Sep 2026 16:44:21 +0200
Subject: [PATCH] fix(util): return null instead of throwing for domains IDN
 rejects

Fixes #107
---
 .../data/resolver/OkHttpRegistrableDomainResolver.kt   | 10 +++++++++-
 .../resolver/OkHttpRegistrableDomainResolverTest.kt    |  9 +++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/core/util/src/main/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolver.kt b/core/util/src/main/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolver.kt
index e6f015998..af8e9fc3a 100644
--- a/core/util/src/main/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolver.kt
+++ b/core/util/src/main/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolver.kt
@@ -17,9 +17,17 @@ internal class OkHttpRegistrableDomainResolver : RegistrableDomainResolver {
         val candidate = if ("://" !in hostOrNull) "https://$hostOrNull" else hostOrNull
 
         val url = candidate.toHttpUrlOrNull()
-            ?: "https://${IDN.toASCII(domain)}".toHttpUrlOrNull()
+            ?: domain.idnToAsciiOrNull()?.let { "https://$it".toHttpUrlOrNull() }
             ?: return null
 
         return url.topPrivateDomain()
     }
+
+    // IDN throws, rather than returning, on anything DNS cannot hold: a label over 63 characters or,
+    // on Android, a name too long overall. Free text in a website field reaches here as is.
+    private fun String.idnToAsciiOrNull(): String? = try {
+        IDN.toASCII(this)
+    } catch (_: IllegalArgumentException) {
+        null
+    }
 }
\ No newline at end of file
diff --git a/core/util/src/test/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolverTest.kt b/core/util/src/test/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolverTest.kt
index 8fcb4e9c0..2ef77dcb8 100644
--- a/core/util/src/test/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolverTest.kt
+++ b/core/util/src/test/kotlin/de/davis/keygo/core/util/data/resolver/OkHttpRegistrableDomainResolverTest.kt
@@ -135,6 +135,15 @@ class OkHttpRegistrableDomainResolverTest {
         assertEquals(expected = expected, actual = result)
     }
 
+    @Test
+    fun `resolves label longer than DNS allows to null`() {
+        val domain = "a".repeat(64) + ".com"
+        val expected = null
+        val result = resolver.resolve(domain)
+
+        assertEquals(expected = expected, actual = result)
+    }
+
     @Test
     fun `resolves IPv4 to null`() {
         val domain = "127.0.0.1"