test: subscribe param compatibility tests and docs (#17)

.github/workflows/add-to-project.yml

@@ -0,0 +1,14 @@
+name: Add to project
+
+on:
+  issues:
+    types: [opened]
+
+jobs:
+  add-to-project:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/add-to-project@v1.0.2
+        with:
+          project-url: https://github.com/orgs/evstack/projects/7
+          github-token: ${{ secrets.ADD_TO_PROJECT_PAT }}

pkg/rpc/core/events.go

@@ -14,6 +14,16 @@ import (
 
 // Subscribe for events via WebSocket.
 // More: https://docs.cometbft.com/v0.37/rpc/#/Websocket/subscribe
+//
+// Param format compatibility (issue #17): CometBFT's JSON-RPC layer
+// normalises incoming subscribe parameters before this function is called via
+// jsonParamsToArgs in rpc/jsonrpc/server/http_json_handler.go. Both the legacy
+// Tendermint map format ({"query": "tm.event='NewBlock'"}) and the array
+// format (["tm.event='NewBlock'"]) are transparently converted to a plain
+// string, so by the time Subscribe runs, query is always a plain Go string
+// regardless of how the WS client sent it. This makes Subscribe compatible
+// with both old Tendermint WS clients that used SubscribeArgs and new
+// CometBFT clients.
 func Subscribe(ctx *rpctypes.Context, query string) (*ctypes.ResultSubscribe, error) {
 	{
 		addr := ctx.RemoteAddr()