fix(amazonq): add handling for new limit mechanism

.changes/next-release/bugfix-554078f3-042e-4b73-8ac4-96085bfc0b8b.json

@@ -0,0 +1,4 @@
+{
+  "type" : "bugfix",
+  "description" : "Amazon Q Feature Dev: display limit reached error message"
+}

plugins/amazonq/chat/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonqFeatureDev/util/FeatureDevService.kt

@@ -65,7 +65,14 @@ class FeatureDevService(val proxyClient: FeatureDevClient, val project: Project)
                 errMssg = e.awsErrorDetails().errorMessage()
                 logger.warn(e) { "Start conversation failed for request: ${e.requestId()}" }
 
-                if (e is software.amazon.awssdk.services.codewhispererruntime.model.ServiceQuotaExceededException) {
+                // BE service will throw ServiceQuota if conversation limit is reached. API Front-end will throw Throttling with this message if conversation limit is reached
+                if (
+                    e is software.amazon.awssdk.services.codewhispererruntime.model.ServiceQuotaExceededException ||
+                    (
+                        e is software.amazon.awssdk.services.codewhispererruntime.model.ThrottlingException &&
+                            e.message?.contains("reached for this month.") == true
+                        )
+                ) {
                     throw MonthlyConversationLimitError(errMssg, operation = FeatureDevOperation.CreateConversation.toString(), desc = null, cause = e.cause)
                 }
             }
@@ -134,10 +141,19 @@ class FeatureDevService(val proxyClient: FeatureDevClient, val project: Project)
                 errMssg = e.awsErrorDetails().errorMessage()
                 logger.warn(e) { "StartTaskAssistCodeGeneration failed for request: ${e.requestId()}" }
 
-                if (e is software.amazon.awssdk.services.codewhispererruntime.model.ServiceQuotaExceededException || (
-                        e is software.amazon.awssdk.services.codewhispererruntime.model.ThrottlingException && e.message?.contains(
-                            "limit for number of iterations on a code generation"
-                        ) == true
+                // API Front-end will throw Throttling if conversation limit is reached. API Front-end monitors StartCodeGeneration for throttling
+                if (e is software.amazon.awssdk.services.codewhispererruntime.model.ThrottlingException &&
+                    e.message?.contains("StartTaskAssistCodeGeneration reached for this month.") == true
+                ) {
+                    throw MonthlyConversationLimitError(errMssg, operation = FeatureDevOperation.StartTaskAssistCodeGeneration.toString(), desc = null, e.cause)
+                }
+                // BE service will throw ServiceQuota if code generation iteration limit is reached
+                else if (e is software.amazon.awssdk.services.codewhispererruntime.model.ServiceQuotaExceededException || (
+                        e is software.amazon.awssdk.services.codewhispererruntime.model.ThrottlingException && (
+                            e.message?.contains(
+                                "limit for number of iterations on a code generation"
+                            ) == true
+                            )
                         )
                 ) {
                     throw CodeIterationLimitException(operation = FeatureDevOperation.StartTaskAssistCodeGeneration.toString(), desc = null, e.cause)

plugins/amazonq/chat/jetbrains-community/tst/software/aws/toolkits/jetbrains/services/amazonqFeatureDev/util/FeatureDevServiceTest.kt

@@ -24,6 +24,7 @@ import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.ContentLengthE
 import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.ExportParseException
 import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.FeatureDevException
 import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.FeatureDevTestBase
+import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.MonthlyConversationLimitError
 import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.clients.FeatureDevClient
 import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.session.CodeGenerationStreamResult
 import software.aws.toolkits.jetbrains.services.amazonqFeatureDev.session.CodeReferenceGenerated
@@ -195,6 +196,37 @@ class FeatureDevServiceTest : FeatureDevTestBase() {
         )
     }
 
+    @Test
+    fun `test startTaskAssistConversation throws ThrottlingException, different case`() {
+        val exampleCWException =
+            ThrottlingException
+                .builder()
+                .awsErrorDetails(
+                    AwsErrorDetails.builder().errorMessage("StartTaskAssistCodeGeneration reached for this month.").build(),
+                ).build()
+        whenever(
+            featureDevClient.startTaskAssistCodeGeneration(
+                testConversationId,
+                testUploadId,
+                userMessage,
+                codeGenerationId = codeGenerationId,
+                currentCodeGenerationId = "EMPTY_CURRENT_CODE_GENERATION_ID",
+            ),
+        ).thenThrow(exampleCWException)
+
+        assertThatThrownBy {
+            featureDevService.startTaskAssistCodeGeneration(
+                testConversationId,
+                testUploadId,
+                userMessage,
+                codeGenerationId = codeGenerationId,
+                currentCodeGenerationId = "EMPTY_CURRENT_CODE_GENERATION_ID",
+            )
+        }.isExactlyInstanceOf(MonthlyConversationLimitError::class.java).withFailMessage(
+            message("amazonqFeatureDev.exception.monthly_limit_error"),
+        )
+    }
+
     @Test
     fun `test startTaskAssistConversation throws ServiceQuotaExceededException`() {
         val exampleCWException =