Cherry-pick BWC fix for system prompt and user instructions (#3437) (#3441)

* BWC (rag processor): add version control for newly added request params (#3125) (#3364)

* gradle spotless

Signed-off-by: Pavan Yekbote <mail2pavanyekbote@gmail.com>

---------

Signed-off-by: Pavan Yekbote <mail2pavanyekbote@gmail.com>
Co-authored-by: opensearch-trigger-bot[bot] <98922864+opensearch-trigger-bot[bot]@users.noreply.github.com>
(cherry picked from commit f4d4481)

Co-authored-by: Pavan Yekbote <mail2pavanyekbote@gmail.com>

Author: opensearch-trigger-bot[bot]

search-processors/src/main/java/org/opensearch/searchpipelines/questionanswering/generative/ext/GenerativeQAParameters.java

@@ -90,6 +90,8 @@ public class GenerativeQAParameters implements Writeable, ToXContentObject {
 
     static final Version MINIMAL_SUPPORTED_VERSION_FOR_BEDROCK_CONVERSE_LLM_MESSAGES = CommonValue.VERSION_2_18_0;
 
+    public static final Version MINIMAL_SUPPORTED_VERSION_FOR_PROMPT_AND_INSTRUCTIONS = CommonValue.VERSION_2_13_0;
+
     @Setter
     @Getter
     private String conversationId;
@@ -200,16 +202,23 @@ public GenerativeQAParameters(StreamInput input) throws IOException {
             this.llmQuestion = input.readString();
         }
 
-        this.systemPrompt = input.readOptionalString();
-        this.userInstructions = input.readOptionalString();
+        if (version.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_PROMPT_AND_INSTRUCTIONS)) {
+            this.systemPrompt = input.readOptionalString();
+            this.userInstructions = input.readOptionalString();
+        }
+
         this.contextSize = input.readInt();
         this.interactionSize = input.readInt();
         this.timeout = input.readInt();
-        this.llmResponseField = input.readOptionalString();
+
+        if (version.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_PROMPT_AND_INSTRUCTIONS)) {
+            this.llmResponseField = input.readOptionalString();
+        }
 
         if (version.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_BEDROCK_CONVERSE_LLM_MESSAGES)) {
             this.llmMessages.addAll(input.readList(MessageBlock::new));
         }
+
     }
 
     @Override
@@ -272,12 +281,18 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeString(llmQuestion);
         }
 
-        out.writeOptionalString(systemPrompt);
-        out.writeOptionalString(userInstructions);
+        if (version.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_PROMPT_AND_INSTRUCTIONS)) {
+            out.writeOptionalString(systemPrompt);
+            out.writeOptionalString(userInstructions);
+        }
+
         out.writeInt(contextSize);
         out.writeInt(interactionSize);
         out.writeInt(timeout);
-        out.writeOptionalString(llmResponseField);
+
+        if (version.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_PROMPT_AND_INSTRUCTIONS)) {
+            out.writeOptionalString(llmResponseField);
+        }
 
         if (version.onOrAfter(MINIMAL_SUPPORTED_VERSION_FOR_BEDROCK_CONVERSE_LLM_MESSAGES)) {
             out.writeList(llmMessages);

search-processors/src/test/java/org/opensearch/searchpipelines/questionanswering/generative/ext/GenerativeQAParamExtBuilderTests.java

@@ -121,6 +121,7 @@ public void testMiscMethods() throws IOException {
         assertNotEquals(builder1, builder2);
         assertNotEquals(builder1.hashCode(), builder2.hashCode());
 
+        // BWC test for bedrock converse params
         StreamOutput so1 = mock(StreamOutput.class);
         when(so1.getVersion()).thenReturn(GenerativeQAParameters.MINIMAL_SUPPORTED_VERSION_FOR_BEDROCK_CONVERSE_LLM_MESSAGES);
         builder1.writeTo(so1);
@@ -130,6 +131,19 @@ public void testMiscMethods() throws IOException {
         when(so2.getVersion()).thenReturn(Version.V_2_17_0);
         builder1.writeTo(so2);
         verify(so2, times(5)).writeOptionalString(any());
+
+        // BWC test for system prompt and instructions
+        StreamOutput so3 = mock(StreamOutput.class);
+        when(so3.getVersion()).thenReturn(GenerativeQAParameters.MINIMAL_SUPPORTED_VERSION_FOR_PROMPT_AND_INSTRUCTIONS);
+        builder1.writeTo(so3);
+        verify(so3, times(5)).writeOptionalString(any());
+        verify(so3, times(1)).writeString(any());
+
+        StreamOutput so4 = mock(StreamOutput.class);
+        when(so4.getVersion()).thenReturn(Version.V_2_12_0);
+        builder1.writeTo(so4);
+        verify(so4, times(2)).writeOptionalString(any());
+        verify(so4, times(1)).writeString(any());
     }
 
     public void testParse() throws IOException {