fix: keep credentials out of the text doctor borrows from its clients

Sanitising the URL in the message was not enough: the client's own error text
went into the detail too, and both psycopg and redis-py quote the URL they were
given. The reason is kept, the endpoint is kept, and the URL, username and
password are taken out of it.

The Redis test raised a generic error, so it asserted the password was absent
without ever exercising the path that leaked. Both tests now raise what the
clients actually raise.

docsgpt/deploy/commands.py

@@ -801,7 +801,7 @@ def _check_postgres(uri: Optional[str]) -> Check:
                 row = cursor.fetchone()
                 current = row[0] if row else None
     except (psycopg.Error, OSError, ValueError) as exc:
-        return Check("postgres", "fail", f"cannot connect: {str(exc).strip()}")
+        return Check("postgres", "fail", f"cannot connect to {_endpoint(uri)}: {_scrub(str(exc).strip(), uri)}")
     head = _migration_head()
     if not current:
         return Check("postgres", "fail", f"PostgreSQL {version}, no schema yet; run `docsgpt migrate`")
@@ -811,8 +811,8 @@ def _check_postgres(uri: Optional[str]) -> Check:
     return Check("postgres", "ok", f"PostgreSQL {version}, schema at {current}")
 
 
-def _redis_endpoint(url: str) -> str:
-    """A Redis URL without its credentials: this ends up on a terminal, in CI logs and in issues."""
+def _endpoint(url: str) -> str:
+    """A URL without its credentials: this ends up on a terminal, in CI logs and in issues."""
     try:
         parts = urlsplit(url)
     except ValueError:
@@ -823,6 +823,21 @@ def _redis_endpoint(url: str) -> str:
     return f"{parts.scheme}://{host}{parts.path}" if host else "the configured URL"
 
 
+def _scrub(text: str, url: Optional[str]) -> str:
+    """Client errors quote the URL they were handed, credentials and all, so take them back out."""
+    if not url:
+        return text
+    text = text.replace(url, _endpoint(url))
+    try:
+        parts = urlsplit(url)
+    except ValueError:
+        return text
+    for secret in (parts.password, parts.username):
+        if secret:
+            text = text.replace(secret, "...")
+    return text
+
+
 def _check_redis(urls: Mapping[str, str]) -> Check:
     """Ping every Redis the settings name; they are usually one server, three databases."""
     if not urls:
@@ -835,7 +850,9 @@ def _check_redis(urls: Mapping[str, str]) -> Check:
         try:
             redis.Redis.from_url(url, socket_connect_timeout=3).ping()
         except Exception as exc:  # noqa: BLE001 - every client error here is the same finding
-            return Check("redis", "fail", f"{label} ({_redis_endpoint(url)}) does not answer: {str(exc).strip()}")
+            return Check(
+                "redis", "fail", f"{label} ({_endpoint(url)}) does not answer: {_scrub(str(exc).strip(), url)}"
+            )
     return Check("redis", "ok", f"answering on {len(urls)} database(s)")
 
 

tests/deploy/test_doctor.py

@@ -213,6 +213,22 @@ class TestPostgresCheck:
         assert check.level == "fail"
         assert "connection refused" in check.detail
 
+    def test_a_database_password_is_never_printed(self, monkeypatch):
+        """psycopg quotes the connection string it was given, which carries the password."""
+        import psycopg
+
+        uri = "postgresql://docsgpt:hunter2@db.example.com:5432/docsgpt"
+
+        def refuse(*args, **kwargs):
+            raise psycopg.OperationalError(f'connection to "{uri}" failed: timeout expired')
+
+        monkeypatch.setattr(psycopg, "connect", refuse)
+        check = commands._check_postgres(uri)
+        assert check.level == "fail"
+        assert "hunter2" not in check.detail
+        assert "db.example.com:5432" in check.detail, "the endpoint still has to be identifiable"
+        assert "timeout expired" in check.detail, "and the reason has to survive the scrubbing"
+
     def test_without_a_uri_at_all(self):
         check = commands._check_postgres(None)
         assert check.level == "fail"
@@ -251,7 +267,8 @@ class TestRedisCheck:
         def from_url(cls, url, **kwargs):
             class Client:
                 def ping(self):
-                    raise ConnectionError("connection refused")
+                    # redis-py quotes the URL it was handed, which is how the credentials got out.
+                    raise ConnectionError(f"no route to {url}")
 
             return Client()
 
@@ -263,7 +280,7 @@ class TestRedisCheck:
         assert "redis.example.com:6380/0" in check.detail, "the endpoint still has to be identifiable"
 
     def test_a_malformed_url_is_not_echoed_either(self):
-        assert commands._redis_endpoint("redis://[::1") == "the configured URL"
+        assert commands._endpoint("redis://[::1") == "the configured URL"
 
     def test_without_any_redis_configured(self):
         assert commands._check_redis({}).level == "fail"