Improve error recovery during message deserialization and update workflows

Signed-off-by: Sergey Karpov <[email protected]>

Author: skarpovdev

.github/workflows/validate-pr.yml

@@ -3,29 +3,38 @@ name: Validate PR
 on:
   workflow_dispatch:
   pull_request:
-    branches: [main]
+    branches: [ main ]
 
 concurrency:
-    group: ${{ github.workflow }}-${{ github.ref }}
-    cancel-in-progress: true
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
   validate-pr:
     runs-on: macos-latest
     name: Validate PR
     steps:
       - uses: actions/checkout@v4
+
       - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
           java-version: '21'
           distribution: 'temurin'
+
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
 
       - name: Clean Build with Gradle
         run: ./gradlew clean build
 
+      - name: Upload JUnit test results
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: junit-results
+          path: '**/build/test-results/test/*.xml'
+
       - name: Disable Auto-Merge on Fail
         if: failure()
         run: gh pr merge --disable-auto "$PR_URL"

kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/ReadBuffer.kt

@@ -44,7 +44,17 @@ public class ReadBuffer {
         try {
             return deserializeMessage(line)
         } catch (e: Exception) {
-            logger.error(e) { "Failed to deserialize message from line: $line\nSkipping..." }
+            logger.error(e) { "Failed to deserialize message from line: $line\nAttempting to recover..." }
+            // if there is a non-JSON object prefix, try to parse from the first '{' onward.
+            val braceIndex = line.indexOf('{')
+            if (braceIndex != -1) {
+                val trimmed = line.substring(braceIndex)
+                try {
+                    return deserializeMessage(trimmed)
+                } catch (ignored: Exception) {
+                    logger.error(ignored) { "Recovery failed for line: $line\nSkipping..." }
+                }
+            }
         }
 
         return null

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/StdioClientTransportTest.kt

@@ -10,7 +10,6 @@ import org.junit.jupiter.api.Test
 class StdioClientTransportTest : BaseTransportTest() {
     @Test
     fun `should start then close cleanly`() = runTest {
-        // Run process "/usr/bin/tee"
         val processBuilder = ProcessBuilder("/usr/bin/tee")
         val process = processBuilder.start()
 
@@ -24,6 +23,7 @@ class StdioClientTransportTest : BaseTransportTest() {
 
         testClientOpenClose(client)
 
+        process.waitFor()
         process.destroy()
     }