fix(azcosmos): remove no-op PopulateCompositeContinuationToken from ChangeFeedResponse

sdk/data/azcosmos/CHANGELOG.md

@@ -10,6 +10,8 @@
 
 ### Breaking Changes
 
+* Removed `ChangeFeedResponse.PopulateCompositeContinuationToken()`. The method is no longer needed: `GetChangeFeed` now populates `ChangeFeedResponse.ContinuationToken` directly with the multi-range composite token. Callers who built single-range tokens manually can use `GetCompositeContinuationToken()` instead.
+
 ### Bugs Fixed
 
 * Fixed `GetChangeFeed` to survive partition splits: customer-supplied `FeedRange`s are now overlap-matched against the routing map, `410/Gone` triggers a cache refresh and bounded retry, split parents expand into per-child queue entries (inheriting the parent's ETag), and the continuation token persists multi-range state across calls. Continuation tokens are guarded against cross-container reuse. See [PR 26768](https://github.com/Azure/azure-sdk-for-go/pull/26768).

sdk/data/azcosmos/cosmos_change_feed_response.go

@@ -59,27 +59,6 @@ func newChangeFeedResponse(resp *http.Response) (ChangeFeedResponse, error) {
 	return response, nil
 }
 
-// PopulateCompositeContinuationToken generates and sets the composite continuation
-// token from response.FeedRange + response.ETag. Retained for back-compat.
-//
-// In the multi-range queue-driven GetChangeFeed path, response.ContinuationToken
-// is already populated with the multi-range composite token by the drain loop
-// itself. This method is therefore a no-op when ContinuationToken is non-empty
-// — overwriting it with a single-range token rebuilt from the per-head
-// FeedRange would lose the multi-range queue state and cause callers that
-// resume with the resulting token to skip subsequent ranges after a split.
-func (response *ChangeFeedResponse) PopulateCompositeContinuationToken() {
-	if response.ContinuationToken != "" {
-		return
-	}
-	if response.FeedRange != nil && response.ETag != "" {
-		compositeToken, err := response.GetCompositeContinuationToken()
-		if err == nil && compositeToken != "" {
-			response.ContinuationToken = compositeToken
-		}
-	}
-}
-
 // GetContinuation from ChangeFeedResponse
 func (c ChangeFeedResponse) GetContinuation() string {
 	return string(c.ETag)

sdk/data/azcosmos/cosmos_change_feed_response_test.go

@@ -139,14 +139,16 @@ func TestChangeFeedResponseWithFeedRange(t *testing.T) {
 		MaxExclusive: "FF",
 	}
 
-	parsedResponse.PopulateCompositeContinuationToken()
-
-	if parsedResponse.ContinuationToken == "" {
-		t.Fatal("expected CompositeContinuationToken to be populated, but it was empty")
+	tokenStr, err := parsedResponse.GetCompositeContinuationToken()
+	if err != nil {
+		t.Fatalf("GetCompositeContinuationToken returned error: %v", err)
+	}
+	if tokenStr == "" {
+		t.Fatal("expected GetCompositeContinuationToken to return a non-empty token")
 	}
 
 	var compositeToken compositeContinuationToken
-	err = json.Unmarshal([]byte(parsedResponse.ContinuationToken), &compositeToken)
+	err = json.Unmarshal([]byte(tokenStr), &compositeToken)
 	if err != nil {
 		t.Fatalf("failed to unmarshal composite token: %v", err)
 	}
@@ -211,9 +213,11 @@ func TestChangeFeedResponseWithoutFeedRange(t *testing.T) {
 		t.Fatalf("failed to create ChangeFeedResponse: %v", err)
 	}
 
-	parsedResponse.PopulateCompositeContinuationToken()
-
-	if parsedResponse.ContinuationToken != "" {
-		t.Errorf("expected CompositeContinuationToken to be empty, but got: %q", parsedResponse.ContinuationToken)
+	tokenStr, err := parsedResponse.GetCompositeContinuationToken()
+	if err != nil {
+		t.Fatalf("GetCompositeContinuationToken returned error: %v", err)
+	}
+	if tokenStr != "" {
+		t.Errorf("expected GetCompositeContinuationToken to return empty string when FeedRange is nil, got: %q", tokenStr)
 	}
 }

sdk/data/azcosmos/cosmos_container_change_feed.go

@@ -383,8 +383,7 @@ func (c *ContainerClient) getChangeFeedForQueue(
 		// Capture the response body's _rid into the token's ResourceID on first
 		// successful response. This keeps the cross-container guard meaningful
 		// across resume — token-issued-by-this-container always carries the
-		// container's RID — and matches pre-F1 PopulateCompositeContinuationToken
-		// semantics that downstream tests rely on.
+		// container's RID.
 		if token.ResourceID == "" && response.ResourceID != "" {
 			token.ResourceID = response.ResourceID
 		}