fix: accept cln-form order scid for closed channels

Author: jvsena42

app/src/main/java/to/bitkit/ext/ShortChannelId.kt

@@ -12,10 +12,18 @@ fun ULong.formattedAsShortChannelId(): String {
     return "${blockHeight}x${txIndex}x$outputIndex"
 }
 
+private val CLN_SHORT_CHANNEL_ID = Regex("""\d+x\d+x\d+""")
+
 /**
- * Short channel id for display. Uses the channel's own scid (open channels) and, for closed
- * channels which carry none, the scid from the confidently-linked order. Null when unavailable.
+ * Short channel id for display. Uses the channel's own scid (open channels, a numeric BOLT scid)
+ * and, for closed channels which carry none, the scid from the confidently-linked Blocktank order.
+ * Blocktank delivers it already in `block x tx x output` form, so an `x`-formatted value is kept
+ * as-is and only a numeric value is decoded. Null when unavailable.
  */
-internal fun resolveDisplayShortChannelId(channelScid: ULong?, linkedOrderScid: String?): String? =
-    channelScid?.formattedAsShortChannelId()
-        ?: linkedOrderScid?.toULongOrNull()?.formattedAsShortChannelId()
+internal fun resolveDisplayShortChannelId(channelScid: ULong?, linkedOrderScid: String?): String? {
+    channelScid?.let { return it.formattedAsShortChannelId() }
+
+    val orderScid = linkedOrderScid?.takeIf { it.isNotBlank() } ?: return null
+    orderScid.toULongOrNull()?.let { return it.formattedAsShortChannelId() }
+    return orderScid.takeIf { CLN_SHORT_CHANNEL_ID.matches(it) }
+}

app/src/test/java/to/bitkit/ext/ShortChannelIdTest.kt

@@ -41,21 +41,26 @@ class ShortChannelIdTest : BaseUnitTest() {
     }
 
     @Test
-    fun `resolveDisplayShortChannelId falls back to linked order scid for closed channel`() {
-        val result = resolveDisplayShortChannelId(
-            channelScid = null,
-            linkedOrderScid = "854845001888432128",
-        )
+    fun `resolveDisplayShortChannelId keeps cln-form linked order scid for closed channel`() {
+        // Blocktank delivers the order scid already in `block x tx x output` form.
+        val result = resolveDisplayShortChannelId(channelScid = null, linkedOrderScid = "792906x599x1")
+        assertEquals("792906x599x1", result)
+    }
+
+    @Test
+    fun `resolveDisplayShortChannelId decodes numeric linked order scid`() {
+        val result = resolveDisplayShortChannelId(channelScid = null, linkedOrderScid = "854845001888432128")
         assertEquals("777477x916x0", result)
     }
 
     @Test
     fun `resolveDisplayShortChannelId returns null when both unavailable`() {
         assertNull(resolveDisplayShortChannelId(channelScid = null, linkedOrderScid = null))
+        assertNull(resolveDisplayShortChannelId(channelScid = null, linkedOrderScid = ""))
     }
 
     @Test
-    fun `resolveDisplayShortChannelId returns null for non-numeric order scid`() {
-        assertNull(resolveDisplayShortChannelId(channelScid = null, linkedOrderScid = "not-a-number"))
+    fun `resolveDisplayShortChannelId returns null for malformed order scid`() {
+        assertNull(resolveDisplayShortChannelId(channelScid = null, linkedOrderScid = "not-a-scid"))
     }
 }