fix: send_progress_text unicasts to client_id instead of broadcasting

- Default sid to self.client_id when not explicitly provided, matching
  every other WS message dispatch (executing, executed, progress_state, etc.)
- Previously sid=None caused broadcast to all connected clients
- Format signature per ruff, remove redundant comments
- Add unit tests for routing, legacy format, and new prompt_id format

Amp-Thread-ID: https://ampcode.com/threads/T-019ca3ce-c530-75dd-8d68-349e745a022e

server.py

@@ -1233,7 +1233,11 @@ class PromptServer():
         return json_data
 
     def send_progress_text(
-        self, text: Union[bytes, bytearray, str], node_id: str, prompt_id: Optional[str] = None, sid=None
+        self,
+        text: Union[bytes, bytearray, str],
+        node_id: str,
+        prompt_id: Optional[str] = None,
+        sid=None,
     ):
         """Send a progress text message to the client via WebSocket.
 
@@ -1251,15 +1255,15 @@ class PromptServer():
             text = text.encode("utf-8")
         node_id_bytes = str(node_id).encode("utf-8")
 
-        # When prompt_id is provided and client supports the new format,
+        # Auto-resolve sid to the currently executing client
-        # prepend prompt_id as a length-prefixed field before node_id
         target_sid = sid if sid is not None else self.client_id
+
+        # When prompt_id is available and client supports the new format,
+        # prepend prompt_id as a length-prefixed field before node_id
         if prompt_id and feature_flags.supports_feature(
             self.sockets_metadata, target_sid, "supports_progress_text_metadata"
         ):
             prompt_id_bytes = prompt_id.encode("utf-8")
-            # Pack prompt_id length as a 4-byte unsigned integer, followed by prompt_id bytes,
-            # then node_id length as a 4-byte unsigned integer, followed by node_id bytes, then text
             message = (
                 struct.pack(">I", len(prompt_id_bytes))
                 + prompt_id_bytes
@@ -1268,7 +1272,6 @@ class PromptServer():
                 + text
             )
         else:
-            # Pack the node_id length as a 4-byte unsigned integer, followed by the node_id bytes
             message = struct.pack(">I", len(node_id_bytes)) + node_id_bytes + text
 
-        self.send_sync(BinaryEventTypes.TEXT, message, sid)
+        self.send_sync(BinaryEventTypes.TEXT, message, target_sid)

tests-unit/prompt_server_test/send_progress_text_test.py

@@ -0,0 +1,207 @@
+"""Tests for send_progress_text routing and binary format logic.
+
+These tests verify:
+1. sid defaults to client_id (unicast) instead of None (broadcast)
+2. Legacy binary format when prompt_id absent or client unsupported
+3. New binary format with prompt_id when client supports the feature flag
+"""
+
+import struct
+
+from comfy_api import feature_flags
+
+
+# ---------------------------------------------------------------------------
+# Helpers – replicate the packing logic so we can assert on the wire format
+# ---------------------------------------------------------------------------
+
+
+def _unpack_legacy(message: bytes):
+    """Unpack a legacy progress_text binary message -> (node_id, text)."""
+    offset = 0
+    node_id_len = struct.unpack_from(">I", message, offset)[0]
+    offset += 4
+    node_id = message[offset : offset + node_id_len].decode("utf-8")
+    offset += node_id_len
+    text = message[offset:].decode("utf-8")
+    return node_id, text
+
+
+def _unpack_with_prompt_id(message: bytes):
+    """Unpack new format -> (prompt_id, node_id, text)."""
+    offset = 0
+    prompt_id_len = struct.unpack_from(">I", message, offset)[0]
+    offset += 4
+    prompt_id = message[offset : offset + prompt_id_len].decode("utf-8")
+    offset += prompt_id_len
+    node_id_len = struct.unpack_from(">I", message, offset)[0]
+    offset += 4
+    node_id = message[offset : offset + node_id_len].decode("utf-8")
+    offset += node_id_len
+    text = message[offset:].decode("utf-8")
+    return prompt_id, node_id, text
+
+
+# ---------------------------------------------------------------------------
+# Minimal stub that mirrors send_progress_text logic from server.py
+# We can't import server.py directly (it pulls in torch via nodes.py),
+# so we replicate the method body here. If the implementation changes,
+# these tests should be updated in tandem.
+# ---------------------------------------------------------------------------
+
+
+class _StubServer:
+    """Stub that captures send_sync calls and runs the real packing logic."""
+
+    def __init__(self, client_id=None, sockets_metadata=None):
+        self.client_id = client_id
+        self.sockets_metadata = sockets_metadata or {}
+        self.sent = []  # list of (event, data, sid)
+
+    def send_sync(self, event, data, sid=None):
+        self.sent.append((event, data, sid))
+
+    def send_progress_text(self, text, node_id, prompt_id=None, sid=None):
+        if isinstance(text, str):
+            text = text.encode("utf-8")
+        node_id_bytes = str(node_id).encode("utf-8")
+
+        target_sid = sid if sid is not None else self.client_id
+
+        if prompt_id and feature_flags.supports_feature(
+            self.sockets_metadata, target_sid, "supports_progress_text_metadata"
+        ):
+            prompt_id_bytes = prompt_id.encode("utf-8")
+            message = (
+                struct.pack(">I", len(prompt_id_bytes))
+                + prompt_id_bytes
+                + struct.pack(">I", len(node_id_bytes))
+                + node_id_bytes
+                + text
+            )
+        else:
+            message = struct.pack(">I", len(node_id_bytes)) + node_id_bytes + text
+
+        self.send_sync(3, message, target_sid)  # 3 == BinaryEventTypes.TEXT
+
+
+# ===========================================================================
+# Routing tests
+# ===========================================================================
+
+
+class TestSendProgressTextRouting:
+    """Verify sid resolution: defaults to client_id, overridable via sid param."""
+
+    def test_defaults_to_client_id_when_sid_not_provided(self):
+        server = _StubServer(client_id="active-client-123")
+        server.send_progress_text("hello", "node1")
+
+        _, _, sid = server.sent[0]
+        assert sid == "active-client-123"
+
+    def test_explicit_sid_overrides_client_id(self):
+        server = _StubServer(client_id="active-client-123")
+        server.send_progress_text("hello", "node1", sid="explicit-sid")
+
+        _, _, sid = server.sent[0]
+        assert sid == "explicit-sid"
+
+    def test_broadcasts_when_no_client_id_and_no_sid(self):
+        server = _StubServer(client_id=None)
+        server.send_progress_text("hello", "node1")
+
+        _, _, sid = server.sent[0]
+        assert sid is None
+
+
+# ===========================================================================
+# Legacy format tests
+# ===========================================================================
+
+
+class TestSendProgressTextLegacyFormat:
+    """Verify legacy binary format: [4B node_id_len][node_id][text]."""
+
+    def test_legacy_format_no_prompt_id(self):
+        server = _StubServer(client_id="c1")
+        server.send_progress_text("some text", "node-42")
+
+        _, data, _ = server.sent[0]
+        node_id, text = _unpack_legacy(data)
+        assert node_id == "node-42"
+        assert text == "some text"
+
+    def test_legacy_format_when_client_unsupported(self):
+        server = _StubServer(
+            client_id="c1",
+            sockets_metadata={"c1": {"feature_flags": {}}},
+        )
+        server.send_progress_text("text", "node1", prompt_id="prompt-abc")
+
+        _, data, _ = server.sent[0]
+        node_id, text = _unpack_legacy(data)
+        assert node_id == "node1"
+        assert text == "text"
+
+    def test_bytes_input_preserved(self):
+        server = _StubServer(client_id="c1")
+        server.send_progress_text(b"raw bytes", "node1")
+
+        _, data, _ = server.sent[0]
+        node_id, text = _unpack_legacy(data)
+        assert text == "raw bytes"
+
+
+# ===========================================================================
+# New format tests
+# ===========================================================================
+
+
+class TestSendProgressTextNewFormat:
+    """Verify new format: [4B prompt_id_len][prompt_id][4B node_id_len][node_id][text]."""
+
+    def test_includes_prompt_id_when_supported(self):
+        server = _StubServer(
+            client_id="c1",
+            sockets_metadata={
+                "c1": {"feature_flags": {"supports_progress_text_metadata": True}}
+            },
+        )
+        server.send_progress_text("progress!", "node-7", prompt_id="prompt-xyz")
+
+        _, data, _ = server.sent[0]
+        prompt_id, node_id, text = _unpack_with_prompt_id(data)
+        assert prompt_id == "prompt-xyz"
+        assert node_id == "node-7"
+        assert text == "progress!"
+
+    def test_new_format_with_explicit_sid(self):
+        server = _StubServer(
+            client_id=None,
+            sockets_metadata={
+                "my-sid": {"feature_flags": {"supports_progress_text_metadata": True}}
+            },
+        )
+        server.send_progress_text("txt", "n1", prompt_id="p1", sid="my-sid")
+
+        _, data, sid = server.sent[0]
+        assert sid == "my-sid"
+        prompt_id, node_id, text = _unpack_with_prompt_id(data)
+        assert prompt_id == "p1"
+        assert node_id == "n1"
+        assert text == "txt"
+
+
+# ===========================================================================
+# Feature flag tests
+# ===========================================================================
+
+
+class TestProgressTextFeatureFlag:
+    """Verify the supports_progress_text_metadata flag exists in server features."""
+
+    def test_flag_in_server_features(self):
+        features = feature_flags.get_server_features()
+        assert "supports_progress_text_metadata" in features
+        assert features["supports_progress_text_metadata"] is True