Create a standard config :grpc_small_clients for binary-size sensitive

clients. This includes Android, iOS, and a newly-introduced opt-in flag
--//:small_clients.

My assumption is that it will be rare for clients to take opt-out features
piecemeal - if they are size constrained, they will want every possible
opt-out. I've left the existing opt-outs in place for current users, but
future features can decide if they need their own flag or not.

PiperOrigin-RevId: 789820421

Author: msjarrett

BUILD

@@ -48,6 +48,16 @@ exports_files(
     visibility = ["//:__subpackages__"],
 )
 
+bool_flag(
+    name = "small_client",
+    build_setting_default = False,
+)
+
+config_setting(
+    name = "small_client_flag",
+    flag_values = {":small_client": "true"},
+)
+
 config_setting(
     name = "grpc_no_ares",
     values = {"define": "grpc_no_ares=true"},
@@ -122,53 +132,52 @@ config_setting(
     values = {"define": "use_systemd=true"},
 )
 
+config_setting(
+    name = "fuchsia",
+    constraint_values = ["@platforms//os:fuchsia"],
+)
+
+# Automatically disable certain deps for space-constrained clients where
+# optional features may not be needed and binary size is more important.
+# This includes mobile clients, and builds which request it explicitly.
 selects.config_setting_group(
-    name = "grpc_no_xds",
+    name = "grpc_small_clients",
     match_any = [
-        ":grpc_no_xds_define",
-        # In addition to disabling XDS support when --define=grpc_no_xds=true is
-        # specified, we also disable it on mobile platforms where it is not
-        # likely to be needed and where reducing the binary size is more
-        # important.
+        ":small_client_flag",  # --//:small_client
         ":android",
         ":ios",
     ],
 )
 
+selects.config_setting_group(
+    name = "grpc_no_xds",
+    match_any = [
+        ":grpc_no_xds_define",  # --define=grpc_no_xds=true
+        ":grpc_small_clients",
+    ],
+)
+
 selects.config_setting_group(
     name = "grpc_no_ztrace",
     match_any = [
-        ":grpc_no_ztrace_define",
-        # In addition to disabling ztrace support when --define=grpc_no_ztrace=true is
-        # specified, we also disable it on mobile platforms where it is not
-        # likely to be needed and where reducing the binary size is more
-        # important.
-        ":android",
-        ":ios",
+        ":grpc_no_ztrace_define",  # --define=grpc_no_ztrace=true
+        ":grpc_small_clients",
     ],
 )
 
 selects.config_setting_group(
     name = "grpc_no_rls",
     match_any = [
-        ":grpc_no_rls_flag",
-        # Disable RLS support on mobile platforms where it is not likely to be
-        # needed and where reducing the binary size is more important.
-        ":android",
-        ":ios",
+        ":grpc_no_rls_flag",  # --//:disable_grpc_rls
+        ":grpc_small_clients",
     ],
 )
 
 selects.config_setting_group(
     name = "grpc_experiments_are_final",
     match_any = [
-        ":grpc_experiments_are_final_define",
-        # In addition to disabling experiments when
-        # --define=grpc_experiments_are_final=true is specified, we also disable
-        # them on mobile platforms where runtime configuration of experiments is unlikely to be needed and where
-        # reducing the binary size is more important.
-        ":android",
-        ":ios",
+        ":grpc_experiments_are_final_define",  # --define=grpc_experiments_are_final=true
+        ":grpc_small_clients",
     ],
 )
 

src/core/BUILD

@@ -79,13 +79,8 @@ config_setting(
 selects.config_setting_group(
     name = "grpc_no_filter_fusion",
     match_any = [
-        ":grpc_no_filter_fusion_define",
-        # In addition to disabling filter fusion support when
-        # --define=grpc_no_filter_fusion=true is specified, we also disable it
-        # on mobile platforms where it is not likely to be needed and where
-        # reducing the binary size is more important.
-        "//:android",
-        "//:ios",
+        ":grpc_no_filter_fusion_define",  # --define=grpc_no_filter_fusion=true
+        "//:grpc_small_clients",
     ],
 )