fix: return the compiled port if PQport returns an empty string

Looking at the docs this seems the default value when an empty string is
specified, as opposite as the value in the PGPORT env var. See
<https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-PORT>.

This change is an improvement on top of 40dfa0b, where we allowed PGport
to return NULL. This is likely a libpq bug (reported in
<https://www.postgresql.org/message-id/CA%2Bmi_8YTS8WPZPO0PAb2aaGLwHuQ0DEQRF0ZMnvWss4y9FwDYQ%40mail.gmail.com>)
but now it's in the wild so we better support it rather than dying of
assert or by int()'ing an empty string.

diff --git a/docs/news.rst b/docs/news.rst
index bac2f5f5128e0f8dd19f117665491fefa690e834..e253078ffd8522f174b3104fd17d0f35732848ac 100644 (file)
--- a/docs/news.rst
+++ b/docs/news.rst
@@ -24,6 +24,8 @@ Psycopg 3.2.8 (unreleased)
 - Don't process further connection attempts after Ctrl-C (:ticket:`#1077`).
 - Fix cursors to correctly iterate over rows even if their row factory
   returns `None` (:ticket:`#1073`).
+- Fix `ConnectionInfo.port` when the port is specified as an empty string
+  (:ticket:`#1078`).
 
 
 Current release

diff --git a/psycopg/psycopg/_connection_info.py b/psycopg/psycopg/_connection_info.py
index 0db591310c25bda6261d2bd97a7ffdc0367b26a6..cf6896cf2ff8ac56e7e6f733b8ced0404145c2bb 100644 (file)
--- a/psycopg/psycopg/_connection_info.py
+++ b/psycopg/psycopg/_connection_info.py
@@ -9,6 +9,7 @@ from __future__ import annotations
 from pathlib import Path
 from datetime import tzinfo
 
+from . import errors as e
 from . import pq
 from ._tz import get_tzinfo
 from .conninfo import make_conninfo
@@ -40,7 +41,21 @@ class ConnectionInfo:
     @property
     def port(self) -> int:
         """The port of the active connection. See :pq:`PQport()`."""
-        return int(self._get_pgconn_attr("port"))
+        if sport := self._get_pgconn_attr("port"):
+            return int(sport)
+        return self._get_compiled_port()
+
+    def _get_compiled_port(sef) -> int:
+        # As per docs: an empty string means the build default, not e.g.
+        # something configured by PGPORT
+        # https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-PORT
+        for info in pq.Conninfo().get_defaults():
+            if info.keyword == b"port":
+                if info.compiled:
+                    return int(info.compiled)
+                break
+
+        raise e.InternalError("couldn't find the connection port")
 
     @property
     def dbname(self) -> str:

diff --git a/tests/test_connection_info.py b/tests/test_connection_info.py
index e7b45909bab338fc168b935715f6a2aeab32840d..ea731ee0edf21f7d494a92a552a8a2a40d9ca3b7 100644 (file)
--- a/tests/test_connection_info.py
+++ b/tests/test_connection_info.py
@@ -44,6 +44,17 @@ def test_port(conn):
         conn.info.port
 
 
+@pytest.mark.skipif(psycopg.pq.__impl__ != "python", reason="can't monkeypatch C")
+def test_blank_port(conn, monkeypatch):
+    monkeypatch.setenv("PGPORT", "9999")
+    monkeypatch.setattr(
+        psycopg.pq._pq_ctypes, "PQport", lambda self: b""  # type: ignore[attr-defined]
+    )
+    assert conn.pgconn.port == b""
+    # assume 5432 is the compiled value
+    assert conn.info.port == 5432
+
+
 def test_get_params(conn, dsn):
     info = conn.info.get_parameters()
     for k, v in conninfo_to_dict(dsn).items():