ci(python): expand driver compatibility coverage

Author: youngsofun

AGENTS.md

@@ -29,6 +29,12 @@ This repository is a Rust workspace for BendSQL plus a separate frontend, langua
   Format: `type(scope): description` or `type: description`.
   Allowed types: `feat`, `fix`, `docs`, `style`, `refactor`, `perf`, `test`, `build`, `ci`, `chore`, `revert`.
 
+## Python Binding Compatibility Tests
+
+- Databend CI can run the latest Python binding tests against older driver versions, and BendSQL keeps a similar compatibility matrix so failures are caught here without blocking the main Databend repository.
+- When adding or changing tests in `bindings/python/tests/**/steps/binding.py`, guard queries, API usage, and assertions that depend on a particular driver or server version with the existing `DRIVER_VERSION` and/or `DB_VERSION` checks. Refer to the existing uses of these variables in the `binding.py` files: execute only the version-dependent portion when the tested version supports it, while leaving version-independent coverage unconditional.
+- Set each version boundary to the first release that supports the behavior. Do not make the older-driver/newer-test compatibility jobs require behavior that is only available in newer driver or server releases.
+
 ## Task Routing
 
 - Rust behavior, CLI flags, REPL, output, or public Rust API changes: read `agents/rust-workspace.md`

bindings/python/tests/asyncio/steps/binding.py

@@ -24,7 +24,10 @@
 tc = unittest.TestCase()
 
 os.environ["DATABEND_DRIVER_HEARTBEAT_INTERVAL_SECONDS"] = "1"
-os.environ["RUST_LOG"] = "warn,databend_driver=debug,databend_client=debug"
+os.environ.setdefault(
+    "RUST_LOG",
+    "warn,databend_driver=debug,databend_client=debug",
+)
 import databend_driver
 
 NOW = int(time.time())

bindings/python/tests/blocking/steps/binding.py

@@ -25,7 +25,10 @@
 from behave import given, when, then
 
 os.environ["DATABEND_DRIVER_HEARTBEAT_INTERVAL_SECONDS"] = "1"
-os.environ["RUST_LOG"] = "warn,databend_driver=debug,databend_client=debug"
+os.environ.setdefault(
+    "RUST_LOG",
+    "warn,databend_driver=debug,databend_client=debug",
+)
 import databend_driver
 
 NOW = int(time.time())

bindings/python/tests/cursor/steps/binding.py

@@ -21,7 +21,10 @@
 from behave import given, when, then
 
 os.environ["DATABEND_DRIVER_HEARTBEAT_INTERVAL_SECONDS"] = "1"
-os.environ["RUST_LOG"] = "warn,databend_driver=debug,databend_client=debug"
+os.environ.setdefault(
+    "RUST_LOG",
+    "warn,databend_driver=debug,databend_client=debug",
+)
 import databend_driver
 
 NOW = int(time.time())

tests/nox/noxfile.py

@@ -49,7 +49,7 @@ def new_driver_with_old_servers(session, db_version, query_result_format):
 
 
 def generate_params2():
-    for driver_version in ["0.28.2", "0.28.1"]:
+    for driver_version in ["0.27.6", "0.33.6", "0.34.0", "0.34.2"]:
         for query_result_format in ["arrow", "json"]:
             v = tuple(map(int, driver_version.split(".")))
             if query_result_format == "arrow" and v <= (0, 30, 3):