improve error when calling sqlcmd

CHANGELOG.md

@@ -14,6 +14,7 @@
 * [Fix] Current connection and switching connections message only displayed when `feedback>=1`
 * [Fix] `--persist/--persist-replace` perform `ROLLBACK` automatically when needed
 * [Fix] `ResultSet` footer (when `displaylimit` truncates results and when showing how to convert to a data frame) now appears in the `ResultSet` plain text representation (#682)
+* [Fix] Improve error when calling `%sqlcmd` (#761)
 * [API Change] When loading connections from a `.ini` file via `%sql --section section_name`, the section name is set as the connection alias
 * [API Change] Starting connections from a `.ini` file via `%sql [section_name]` has been deprecated
 * [Doc] Fixes documentation inaccuracy that said `:variable` was deprecated (we brought it back in `0.9.0`)

src/sql/magic_cmd.py

@@ -11,6 +11,7 @@
 from sql.cmd.profile import profile
 from sql.cmd.explore import explore
 from sql.cmd.snippets import snippets
+from sql.connection import ConnectionManager
 
 try:
     from traitlets.config.configurable import Configurable
@@ -51,6 +52,8 @@ def _validate_execute_inputs(self, line):
             "explore",
             "snippets",
         ]
+        CONNECTION_INDEPENDENT_COMMANDS = ["snippets"]
+        SUPPORTED_BY_BOTH_COMMANDS = ["profile"]
 
         VALID_COMMANDS_MSG = (
             f"Missing argument for %sqlcmd. "
@@ -64,8 +67,18 @@ def _validate_execute_inputs(self, line):
             command, others = split[0].strip(), split[1:]
 
             if command in AVAILABLE_SQLCMD_COMMANDS:
-                if command not in ["profile"]:
+                if (
+                    command not in CONNECTION_INDEPENDENT_COMMANDS
+                    and not ConnectionManager.current
+                ):
+                    raise exceptions.RuntimeError("No active connection")
+
+                if command not in [
+                    *CONNECTION_INDEPENDENT_COMMANDS,
+                    *SUPPORTED_BY_BOTH_COMMANDS,
+                ]:
                     util.support_only_sql_alchemy_connection("%sqlcmd")
+
                 return self.execute(command, others)
             else:
                 raise exceptions.UsageError(

src/tests/test_magic_cmd.py

@@ -125,6 +125,54 @@ def test_error(tmp_empty, ip, cell, error_message):
     assert str(excinfo.value) == error_message
 
 
+@pytest.mark.parametrize(
+    "command",
+    [
+        "tables",
+        "columns",
+        "test",
+        "profile",
+        "explore",
+    ],
+)
+def test_sqlcmd_error_when_no_connection(ip_empty, command):
+    with pytest.raises(UsageError) as excinfo:
+        ip_empty.run_cell(f"%sqlcmd {command}")
+
+    assert excinfo.value.error_type == "RuntimeError"
+    assert str(excinfo.value) == "No active connection"
+
+
+def test_sqlcmd_snippets_when_no_connection(ip_empty, capsys):
+    for key in list(store):
+        del store[key]
+
+    ip_empty.run_cell("%sqlcmd snippets")
+    captured = capsys.readouterr()
+    assert "No snippets stored" in captured.out
+
+
+@pytest.mark.parametrize(
+    "query",
+    [
+        ("%sqlcmd tables"),
+        ("%sqlcmd columns --table penguins.csv"),
+        ("%sqlcmd test --table penguins.csv  --column body_mass_g --greater 2900"),
+        ("%sqlcmd explore --table penguins.csv"),
+    ],
+)
+def test_sqlcmd_not_supported_error(ip_with_connections, query, capsys):
+    ip_with_connections.run_cell("%sql duckdb_dbapi")
+    expected_error_message = (
+        "%sqlcmd is only supported with SQLAlchemy connections, "
+        "not with DBAPI connections"
+    )
+    with pytest.raises(UsageError) as excinfo:
+        ip_with_connections.run_cell(query)
+
+    assert expected_error_message in str(excinfo.value)
+
+
 def test_tables(ip):
     out = ip.run_cell("%sqlcmd tables").result._repr_html_()
     assert "author" in out