connect() timeout validation + copy cursor.description on read

ISSUE (cycle 6) — dqlitedbapi.connect() accepted any timeout value
(negative, NaN, infinite) and quietly passed it down. Now rejects
non-positive / non-finite values up front with ValueError, matching
DqliteConnection's validation.

ISSUE (cycle 6) — cursor.description was returning the internal list
by reference. A caller mutating it (cursor.description.clear(),
cursor.description[0] = ...) corrupted the cursor's state. Now
returns a fresh shallow copy per access in both sync and async
cursors.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqlitedbapi/__init__.py

@@ -93,9 +93,16 @@ def connect(
     Args:
         address: Node address in "host:port" format
         database: Database name to open
-        timeout: Connection timeout in seconds
+        timeout: Connection timeout in seconds — must be a positive
+            finite number. ``0``, negatives, and non-finite values are
+            rejected here rather than silently passed through to the
+            underlying connection.
 
     Returns:
         A Connection object
     """
+    import math
+
+    if not math.isfinite(timeout) or timeout <= 0:
+        raise ValueError(f"timeout must be a positive finite number, got {timeout}")
     return Connection(address, database=database, timeout=timeout)

src/dqlitedbapi/aio/cursor.py

@@ -35,8 +35,14 @@ def __init__(self, connection: "AsyncConnection") -> None:
     def description(
         self,
     ) -> list[tuple[str, int | None, None, None, None, None, None]] | None:
-        """Column descriptions for the last query."""
-        return self._description
+        """Column descriptions for the last query.
+
+        Returns a fresh shallow copy so a caller can't corrupt internal
+        cursor state by mutating the returned list.
+        """
+        if self._description is None:
+            return None
+        return list(self._description)
 
     @property
     def rowcount(self) -> int:

src/dqlitedbapi/cursor.py

@@ -146,8 +146,14 @@ def description(
         ``type_code`` is the wire-level ``ValueType`` integer from the first
         result frame (e.g. 10 for ISO8601, 9 for UNIXTIME). The other fields
         are None — dqlite doesn't expose them.
+
+        Returns a fresh shallow copy each call so that a caller
+        mutating the list (e.g. ``cursor.description.clear()``) can't
+        corrupt the cursor's internal state.
         """
-        return self._description
+        if self._description is None:
+            return None
+        return list(self._description)
 
     @property
     def rowcount(self) -> int: