Merge pull request #7393 from thunderbird/fix_mx_lookup_crash

Avoid crash when MX lookup returns invalid hostname

Author: cketti

core/common/src/main/kotlin/app/k9mail/core/common/net/Domain.kt

@@ -8,3 +8,12 @@ value class Domain(val value: String) {
 }
 
 fun String.toDomain() = Domain(this)
+
+@Suppress("SwallowedException")
+fun String.toDomainOrNull(): Domain? {
+    return try {
+        toDomain()
+    } catch (e: IllegalArgumentException) {
+        null
+    }
+}

feature/autodiscovery/autoconfig/src/main/kotlin/app/k9mail/autodiscovery/autoconfig/MiniDnsMxResolver.kt

@@ -1,7 +1,7 @@
 package app.k9mail.autodiscovery.autoconfig
 
 import app.k9mail.core.common.net.Domain
-import app.k9mail.core.common.net.toDomain
+import app.k9mail.core.common.net.toDomainOrNull
 import org.minidns.hla.ResolverApi
 import org.minidns.record.MX
 
@@ -11,7 +11,7 @@ internal class MiniDnsMxResolver : MxResolver {
 
         val mxNames = result.answersOrEmptySet
             .sortedBy { it.priority }
-            .map { it.target.toString().toDomain() }
+            .mapNotNull { it.target.toString().toDomainOrNull() }
 
         return MxLookupResult(
             mxNames = mxNames,