Do unwrap even if wrapper exception has suppressed exceptions

mirai-core-utils/src/androidMain/kotlin/Actuals.kt

@@ -32,8 +32,10 @@ internal class StacktraceException(override val message: String?, private val st
 
 public actual inline fun <reified E> Throwable.unwrap(): Throwable {
     if (this !is E) return this
-    if (suppressed.isNotEmpty()) return this
     val e = StacktraceException("Unwrapped exception: $this", this.stackTrace)
+    for (throwable in this.suppressed) {
+        e.addSuppressed(throwable)
+    }
     return this.findCause { it !is E }
         ?.also { it.addSuppressed(e) }
         ?: this

mirai-core-utils/src/androidTest/kotlin/AndroidUnwrapTest.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/dev/LICENSE
+ */
+
+package net.mamoe.mirai.utils
+
+import kotlin.test.Test
+import kotlin.test.assertIs
+
+class AndroidUnwrapTest {
+    @Test
+    fun test() {
+        val e =
+            IllegalStateException(
+                OutOfMemoryError().initCause(VerifyError()).apply { addSuppressed(UnsatisfiedLinkError()) }
+            )
+
+        val unwrapped = e.unwrap<IllegalStateException>()
+
+        unwrapped.printStackTrace()
+
+        assertIs<OutOfMemoryError>(unwrapped)
+        assertIs<VerifyError>(unwrapped.cause)
+        assertIs<UnsatisfiedLinkError>(unwrapped.suppressed.first())
+        assertIs<StacktraceException>(unwrapped.suppressed[1])
+    }
+}

mirai-core-utils/src/jvmMain/kotlin/Actuals.kt

@@ -25,7 +25,6 @@ public actual fun String.decodeBase64(): ByteArray {
 
 public actual inline fun <reified E> Throwable.unwrap(): Throwable {
     if (this !is E) return this
-    if (suppressed.isNotEmpty()) return this
     return this.findCause { it !is E }
         ?.also { it.addSuppressed(this) }
         ?: this

mirai-core-utils/src/jvmTest/kotlin/AndroidUnwrapTest.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/dev/LICENSE
+ */
+
+package net.mamoe.mirai.utils
+
+import kotlin.test.Test
+import kotlin.test.assertIs
+
+class JvmUnwrapTest {
+    @Test
+    fun test() {
+        val e =
+            IllegalStateException(
+                OutOfMemoryError().initCause(VerifyError()).apply { addSuppressed(UnsatisfiedLinkError()) }
+            )
+
+        val unwrapped = e.unwrap<IllegalStateException>()
+
+        unwrapped.printStackTrace()
+
+        assertIs<OutOfMemoryError>(unwrapped)
+        assertIs<VerifyError>(unwrapped.cause)
+        assertIs<UnsatisfiedLinkError>(unwrapped.suppressed.first())
+        assertIs<IllegalStateException>(unwrapped.suppressed[1])
+    }
+}