Adjusted import and error message behavior based on types

Author: SoulofAkuma

pandas/compat/_optional.py

@@ -151,7 +151,7 @@ def import_optional_dependency(
     install_name = package_name if package_name is not None else name
 
     msg = (
-        f"`Import {install_name}` failed. {extra} "
+        f"`Import {install_name} failed. {extra} "
         f"Use pip or conda to install the {install_name} package."
     )
     try:

pandas/io/sql.py

@@ -895,13 +895,23 @@ def pandasSQL_builder(
     if isinstance(con, sqlite3.Connection) or con is None:
         return SQLiteDatabase(con)
 
-    sqlalchemy = import_optional_dependency("sqlalchemy", errors="ignore")
+    is_sqlalchemy_type = isinstance(con, str) or con.__module__.startswith("sqlalchemy")
 
-    if isinstance(con, str) and sqlalchemy is None:
-        raise ImportError("Using URI string without sqlalchemy installed.")
+    if is_sqlalchemy_type:
+        try:
+            sqlalchemy = import_optional_dependency(
+                "sqlalchemy", min_version="2.0.36", errors="raise"
+            )
+        except ImportError as e:
+            if isinstance(con, str):
+                raise ImportError(
+                    "Using URI string without matching version of sqlalchemy installed."
+                ) from e
+            else:
+                raise e
 
-    if sqlalchemy is not None and isinstance(con, (str, sqlalchemy.engine.Connectable)):
-        return SQLDatabase(con, schema, need_transaction)
+        if isinstance(con, (str, sqlalchemy.engine.Connectable)):
+            return SQLDatabase(con, schema, need_transaction)
 
     adbc = import_optional_dependency("adbc_driver_manager.dbapi", errors="ignore")
     if adbc and isinstance(con, adbc.Connection):

pandas/tests/io/test_sql.py

@@ -2598,11 +2598,38 @@ def test_sql_open_close(test_frame3):
 @td.skip_if_installed("sqlalchemy")
 def test_con_string_import_error():
     conn = "mysql://root@localhost/pandas"
-    msg = "Using URI string without sqlalchemy installed"
+    msg = "Using URI string without matching version of sqlalchemy installed."
     with pytest.raises(ImportError, match=msg):
         sql.read_sql("SELECT * FROM iris", conn)
 
 
+@td.skip_if_installed("sqlalchemy")
+@pytest.mark.parametrize("conn", sqlalchemy_connectable)
+def test_con_sqlalchemy_import_error(conn, request):
+    conn = request.getfixturevalue(conn)
+    msg = r"Pandas requires version '2\.0\.36' or newer of 'sqlalchemy'.*"
+    with pytest.raises(ImportError, match=msg):
+        _ = pandasSQL_builder(conn)
+
+
+@td.skip_if_no_unsupported_installed("sqlalchemy", min_version="2.0.36")
+@pytest.mark.parametrize("conn", sqlalchemy_connectable)
+def test_con_sqlalchemy_import_error_unsupported(conn, request):
+    conn = request.getfixturevalue(conn)
+    msg = r"Import SQLAlchemy failed\..*"
+    with pytest.raises(ImportError, match=msg):
+        _ = pandasSQL_builder(conn)
+
+
+@td.skip_if_no("sqlalchemy", min_version="2.0.36")
+@pytest.mark.parametrize("conn", sqlalchemy_connectable)
+def test_con_sqlalchemy_connectable(conn, request):
+    conn = request.getfixturevalue(conn)
+    pandas_sql = pandasSQL_builder(conn)
+
+    assert isinstance(pandas_sql, SQLDatabase)
+
+
 @td.skip_if_installed("sqlalchemy")
 def test_con_unknown_dbapi2_class_does_not_error_without_sql_alchemy_installed():
     class MockSqliteConnection:

pandas/util/_test_decorators.py

@@ -43,24 +43,67 @@ def test_foo():
 from pandas.compat._optional import import_optional_dependency
 
 
-def skip_if_installed(package: str) -> pytest.MarkDecorator:
+def skip_if_installed(
+    package: str, min_version: str | None = None
+) -> pytest.MarkDecorator:
     """
     Skip a test if a package is installed.
 
     Parameters
     ----------
     package : str
         The name of the package.
+    min_version: str or None, default None
+        Optional minimum version of the package.
 
     Returns
     -------
     pytest.MarkDecorator
         a pytest.mark.skipif to use as either a test decorator or a
         parametrization mark.
     """
+    msg = f"Skipping because '{package}'"
+    if min_version:
+        msg += f" satisfying a min_version of {min_version}"
+    msg += " is installed."
     return pytest.mark.skipif(
-        bool(import_optional_dependency(package, errors="ignore")),
-        reason=f"Skipping because {package} is installed.",
+        bool(
+            import_optional_dependency(
+                package, min_version=min_version, errors="ignore"
+            )
+        ),
+        reason=msg,
+    )
+
+
+def skip_if_no_unsupported_installed(
+    package: str, min_version: str
+) -> pytest.MarkDecorator:
+    """
+    Skip a test if there is no unsupported version of a package installed.
+    The test will hence be executed only if an unsupported version is installed.
+
+    Parameters
+    ----------
+    package : str
+        The name of the package.
+    min_version: str or None, default None
+        The minimum version of the package.
+
+    Returns
+    -------
+    pytest.MarkDecorator
+        a pytest.mark.skipif to use as either a test decorator or a
+        parametrization mark.
+    """
+    return pytest.mark.skipif(
+        bool(import_optional_dependency(package, errors="ignore"))
+        and not bool(
+            import_optional_dependency(
+                package, min_version=min_version, errors="ignore"
+            )
+        ),
+        reason=f"Skipping because no unsupported version of {package} is installed",
     )