From ffce4b83c23891a9fae663497c7a569640a6f76f Mon Sep 17 00:00:00 2001 From: Daniel Lamping Date: Wed, 21 Oct 2026 14:31:00 +0100 Subject: [PATCH] CP-314775: Restore the HOST_IS_SLAVE parameter name The Java SDK generates the HostIsSlave exception's public field from this parameter name, so renaming it to "Coordinator IP address" turned masterIPAddress into coordinatorIPAddress. That breaks any Java client that reads the field: existing code no longer compiles, and code compiled against an earlier SDK throws NoSuchFieldError when it handles the error. No other SDK uses the name. Co-Authored-By: Claude Opus 5.5 (1M context) Signed-off-by: Daniel Lamping --- ocaml/idl/datamodel_errors.ml | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/ocaml/idl/datamodel_errors.ml b/ocaml/idl/datamodel_errors.ml index 9eefff7967..100b2906f4 100644 --- a/ocaml/idl/datamodel_errors.ml +++ b/ocaml/idl/datamodel_errors.ml @@ -1652,7 +1652,9 @@ let _ = () ; (* Pool errors *) - error Api_errors.host_is_slave ["Coordinator IP address"] + (* The Java SDK names the HostIsSlave field after this parameter + (masterIPAddress), so renaming it is a breaking change. *) + error Api_errors.host_is_slave ["Master IP address"] ~doc: "You cannot make regular API calls directly on a supporter. Please pass \ API calls via the coordinator host."