From db36727e9d299de88e55a32825a4a690ac602ecf Mon Sep 17 00:00:00 2001
From: Anubhav Harsh Sinha <sinhaanubhavharsh@gmail.com>
Date: Tue, 22 Sep 2026 20:24:36 +0530
Subject: [PATCH 1/3] fix: reject SCPI responses that end before their newline

pyserial's readline() returns whatever arrived before the timeout, so a
response cut off mid-line ("12" of "123\n") was returned by query() as
a complete answer. Require the line terminator in query() and in the
text error line read by read_block(), and raise ScpiTimeoutError
otherwise, which is what the Wi-Fi transport already does.
---
 pslab/pico/transport.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/pslab/pico/transport.py b/pslab/pico/transport.py
index ab9490c..c757355 100644
--- a/pslab/pico/transport.py
+++ b/pslab/pico/transport.py
@@ -233,7 +233,8 @@ def query(self, command: str) -> str:
 
         self._write_line(command)
         line = self.transport.readline()
-        if not line:
+        # pyserial returns a partial line without the terminator on timeout.
+        if not line.endswith(b"\n"):
             raise ScpiTimeoutError(f"Timed out waiting for response to {command!r}.")
         return line.decode("ascii", errors="replace").strip()
 
@@ -248,9 +249,10 @@ def read_block(self) -> bytes:
 
         marker = self._read_exact(1)
         if marker != b"#":
-            rest = self.transport.readline()
-            message = (marker + rest).decode("ascii", errors="replace").strip()
-            raise ScpiError(message)
+            line = marker + self.transport.readline()
+            if not line.endswith(b"\n"):
+                raise ScpiTimeoutError("Timed out waiting for SCPI error response.")
+            raise ScpiError(line.decode("ascii", errors="replace").strip())
 
         digit_count_text = self._read_exact(1)
         try:

From a17dadb8c69bba2cea6fc163bbae4c724d380209 Mon Sep 17 00:00:00 2001
From: Anubhav Harsh Sinha <sinhaanubhavharsh@gmail.com>
Date: Tue, 22 Sep 2026 20:24:56 +0530
Subject: [PATCH 2/3] fix: close the Wi-Fi socket when connecting fails

PicoWifiTransport.connect() left the socket open if connect() raised
(connection refused or timed out), leaking one socket per attempt
against an unreachable bridge.
---
 pslab/pico/transport.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/pslab/pico/transport.py b/pslab/pico/transport.py
index c757355..3b7e423 100644
--- a/pslab/pico/transport.py
+++ b/pslab/pico/transport.py
@@ -156,8 +156,12 @@ def connect(self) -> None:
         if self._socket is not None:
             return
         sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        sock.settimeout(self.timeout)
-        sock.connect((self.host, self.port))
+        try:
+            sock.settimeout(self.timeout)
+            sock.connect((self.host, self.port))
+        except BaseException:
+            sock.close()
+            raise
         self._socket = sock
 
     def close(self) -> None:

From 939c661c6e0f17ef056cb938e7f0170463ca2263 Mon Sep 17 00:00:00 2001
From: Anubhav Harsh Sinha <sinhaanubhavharsh@gmail.com>
Date: Tue, 22 Sep 2026 20:25:36 +0530
Subject: [PATCH 3/3] test: cover truncated SCPI responses and failed Wi-Fi
 connects

---
 tests/test_pico_scpi_transport.py | 38 +++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/tests/test_pico_scpi_transport.py b/tests/test_pico_scpi_transport.py
index dbed58f..af7d7c2 100644
--- a/tests/test_pico_scpi_transport.py
+++ b/tests/test_pico_scpi_transport.py
@@ -234,3 +234,41 @@ def test_wifi_readline_wraps_socket_timeout():
 
     with pytest.raises(ScpiTimeoutError):
         transport.readline()
+
+
+class TruncatingTransport(FakeTransport):
+    """Return a response without its newline, as pyserial does on timeout."""
+
+    def write(self, data):
+        self.output.extend(b"12")
+        return len(data)
+
+
+def test_query_rejects_response_without_newline():
+    client = ScpiClient(TruncatingTransport())
+
+    with pytest.raises(ScpiTimeoutError):
+        client.error_count()
+
+
+def test_query_block_rejects_error_line_without_newline():
+    client = ScpiClient(TruncatingTransport())
+
+    with pytest.raises(ScpiTimeoutError):
+        client.query_block("LA:READ?")
+
+
+def test_wifi_connect_closes_socket_when_connect_fails(monkeypatch):
+    class RefusingSocket(FakeSocket):
+        def connect(self, address):
+            raise ConnectionRefusedError
+
+    sock = RefusingSocket([])
+    monkeypatch.setattr(socket, "socket", lambda *args: sock)
+    transport = PicoWifiTransport("example.test")
+
+    with pytest.raises(ConnectionRefusedError):
+        transport.connect()
+
+    assert sock.closed
+    assert not transport.is_open