Fix incomplete JSON response detection (not just empty)

- Added check for suspiciously short responses (< 10 chars) that indicate truncation
- Updated error messages to show actual response content for debugging
- Added test for incomplete JSON response (e.g., just ')')
- Updated release notes to accurately describe the issue

The actual problem was truncated/incomplete JSON responses (like ')'),
not empty responses. This happens when hubs crash or restart mid-response.

Author: jbaruch

RELEASE_NOTES_3.3.md

@@ -3,17 +3,17 @@
 ## Bug Fix: Hub Update Status Monitoring
 
 ### Problem
-During hub update monitoring with polling, the system would fail with "Cannot read Json element because of unexpected end of the input" errors when the hub returned empty responses. This typically happens when:
+During hub update monitoring with polling, the system would fail with "Cannot read Json element because of unexpected end of the input" errors when the hub returned incomplete/truncated JSON responses (e.g., just ")"). This typically happens when:
 - The hub is busy processing an update
-- The hub is temporarily restarting
-- Network issues cause incomplete responses
+- The hub is temporarily restarting or crashing mid-response
+- Network issues cause response truncation
 
 ### Solution
 Added robust error handling and retry logic:
 
-1. **Empty Response Detection**: Check for blank responses before attempting JSON parsing
+1. **Incomplete Response Detection**: Check for empty or suspiciously short responses (< 10 chars) before attempting JSON parsing
 2. **Retry Logic with Exponential Backoff**: Automatically retry failed version checks up to 3 times with increasing delays (2s, 4s, 8s)
-3. **Better Error Messages**: Clear error messages indicating when empty responses are received
+3. **Better Error Messages**: Clear error messages indicating when incomplete/malformed responses are received, showing the actual response content
 
 ### Changes Made
 - Added empty response check in `HubOperations.getHubVersions()`

src/main/kotlin/HubOperations.kt

@@ -71,14 +71,22 @@ object HubOperations {
         val endpoint = "http://${hubIp}/apps/api/${makerApiAppId}/devices/${hub.id}"
         val responseBody = networkClient.getBody(endpoint, mapOf("access_token" to makerApiToken))
 
-        // Check for empty response
+        // Check for empty or very short response (likely incomplete)
         if (responseBody.isBlank()) {
             throw Exception(
                 "Failed to get hub info for hub '${hub.label}' from endpoint '$endpoint': " +
                 "Received empty response. This may happen if the hub is busy or restarting."
             )
         }
 
+        if (responseBody.length < 10) {
+            throw Exception(
+                "Failed to get hub info for hub '${hub.label}' from endpoint '$endpoint': " +
+                "Received incomplete response (${responseBody.length} chars): '$responseBody'. " +
+                "This may happen if the hub is busy, restarting, or experiencing network issues."
+            )
+        }
+        
         try {
             val json = Json.parseToJsonElement(responseBody).jsonObject
             val attributes = json["attributes"] as? JsonArray

src/test/kotlin/integration/RealHubitatApiTest.kt

@@ -283,6 +283,50 @@ class RealHubitatApiTest : FunSpec({
         }
     }
 
+    test("should handle incomplete JSON response") {
+        // Test with incomplete JSON (just a closing paren)
+        val mockEngine = MockEngine { request ->
+            respond(
+                content = ByteReadChannel(")"),
+                status = HttpStatusCode.OK,
+                headers = headersOf(HttpHeaders.ContentType, "application/json")
+            )
+        }
+        
+        val client = HttpClient(mockEngine)
+        val networkClient = KtorNetworkClient(client)
+        
+        val hub = Device.Hub(
+            id = 445,
+            label = "Test Hub",
+            ip = "192.168.1.100",
+            managementToken = "test-token"
+        )
+        
+        try {
+            val result = runCatching {
+                HubOperations.getHubVersions(
+                    hub = hub,
+                    networkClient = networkClient,
+                    hubIp = "192.168.1.100",
+                    makerApiAppId = "398",
+                    makerApiToken = "test-token"
+                )
+            }
+            
+            result.isFailure shouldBe true
+            val error = result.exceptionOrNull()
+            error shouldNotBe null
+            error?.message shouldContain "incomplete response"
+            error?.message shouldContain ")"
+            
+            println("✅ Incomplete JSON handled gracefully: ${error?.message?.take(150)}")
+            
+        } finally {
+            client.close()
+        }
+    }
+    
     test("should handle empty response gracefully") {
         // Test with mocked empty response
         val mockEngine = MockEngine { request ->