From 0627ceb34ecf26f945c10cd519b86ca4c709c30f Mon Sep 17 00:00:00 2001
From: Matthew Keeler <mkeeler@launchdarkly.com>
Date: Thu, 5 Nov 2026 09:32:04 -0500
Subject: [PATCH] feat!: Remove payload filter support from the FDv2 data
 system

The FDv2 streaming and polling requests, and the FDv1 fallback polling
request, no longer send the filter query parameter. FDv2 already logged
that payload filtering was unsupported and that the payload_filter_key
option had no effect, but the requests still sent it. The behavior now
matches the warning.

The FDv1 data system keeps its payload filter support until the FDv1
removal deletes it. The contract tests no longer map the payloadFilter
data system setting. The filtering capabilities stay, because only
harness v2 tests them, against FDv1.
---
 contract-tests/client_entity.rb               |  4 ----
 lib/ldclient-rb/impl/data_system/polling.rb   | 21 +++----------------
 lib/ldclient-rb/impl/data_system/streaming.rb |  1 -
 .../data_system/streaming_headers_spec.rb     |  1 -
 .../streaming_synchronizer_spec.rb            |  1 -
 5 files changed, 3 insertions(+), 25 deletions(-)

diff --git a/contract-tests/client_entity.rb b/contract-tests/client_entity.rb
index 5df1f56a..8d061005 100644
--- a/contract-tests/client_entity.rb
+++ b/contract-tests/client_entity.rb
@@ -52,10 +52,6 @@ def initialize(log, config)
         data_system.fdv1_compatible_synchronizer(build_fdv1_fallback_builder(fdv1_fallback_config))
       end
 
-      if data_system_config[:payloadFilter]
-        opts[:payload_filter_key] = data_system_config[:payloadFilter]
-      end
-
       opts[:data_system_config] = data_system.build
     elsif config[:streaming]
       streaming = config[:streaming]
diff --git a/lib/ldclient-rb/impl/data_system/polling.rb b/lib/ldclient-rb/impl/data_system/polling.rb
index 078352ef..9613a752 100644
--- a/lib/ldclient-rb/impl/data_system/polling.rb
+++ b/lib/ldclient-rb/impl/data_system/polling.rb
@@ -309,17 +309,9 @@ def initialize(sdk_key, http_config, config)
         # @return [Result]
         #
         def fetch(selector)
-          query_params = []
-          query_params << ["filter", @config.payload_filter_key] unless @config.payload_filter_key.nil?
-
-          if selector && selector.defined?
-            query_params << ["basis", selector.state]
-          end
-
           uri = @poll_uri
-          if query_params.any?
-            filter_query = URI.encode_www_form(query_params)
-            uri = "#{uri}?#{filter_query}"
+          if selector && selector.defined?
+            uri = "#{uri}?#{URI.encode_www_form(basis: selector.state)}"
           end
 
           headers = {}
@@ -384,7 +376,7 @@ class HTTPFDv1PollingRequester
         #
         # @param sdk_key [String]
         # @param http_config [HttpConfigOptions] HTTP connection settings
-        # @param config [LaunchDarkly::Config] Used for global header settings and payload_filter_key
+        # @param config [LaunchDarkly::Config] Used for global header settings
         #
         def initialize(sdk_key, http_config, config)
           @etag = nil
@@ -401,14 +393,7 @@ def initialize(sdk_key, http_config, config)
         # @return [Result]
         #
         def fetch(selector)
-          query_params = []
-          query_params << ["filter", @config.payload_filter_key] unless @config.payload_filter_key.nil?
-
           uri = @poll_uri
-          if query_params.any?
-            filter_query = URI.encode_www_form(query_params)
-            uri = "#{uri}?#{filter_query}"
-          end
 
           headers = {}
           Impl::Util.default_http_headers(@sdk_key, @config).each { |k, v| headers[k] = v }
diff --git a/lib/ldclient-rb/impl/data_system/streaming.rb b/lib/ldclient-rb/impl/data_system/streaming.rb
index d3c9a5f4..ad00531b 100644
--- a/lib/ldclient-rb/impl/data_system/streaming.rb
+++ b/lib/ldclient-rb/impl/data_system/streaming.rb
@@ -182,7 +182,6 @@ def sync(ss)
             client.query_params do
               selector = ss.selector
               {
-                "filter" => @config.payload_filter_key,
                 "basis" => (selector.state if selector&.defined?),
               }.compact
             end
diff --git a/spec/impl/data_system/streaming_headers_spec.rb b/spec/impl/data_system/streaming_headers_spec.rb
index 707db3a2..f7c79417 100644
--- a/spec/impl/data_system/streaming_headers_spec.rb
+++ b/spec/impl/data_system/streaming_headers_spec.rb
@@ -15,7 +15,6 @@ module DataSystem
             "Config",
             logger: logger,
             stream_uri: "https://stream.example.com",
-            payload_filter_key: nil,
             socket_factory: nil,
             initial_reconnect_delay: 1,
             instance_id: nil
diff --git a/spec/impl/data_system/streaming_synchronizer_spec.rb b/spec/impl/data_system/streaming_synchronizer_spec.rb
index 6a7ba32e..261b7368 100644
--- a/spec/impl/data_system/streaming_synchronizer_spec.rb
+++ b/spec/impl/data_system/streaming_synchronizer_spec.rb
@@ -17,7 +17,6 @@ module DataSystem
             "Config",
             logger: logger,
             stream_uri: "https://stream.example.com",
-            payload_filter_key: nil,
             socket_factory: nil,
             initial_reconnect_delay: 1,
             instance_id: nil