getredash/redash · error · Exception

'{} is not supported inplace variable

Error message

'{} is not supported inplace variable

What it means

RestrictedPython replaces augmented assignments (+=, -=, etc.) with calls to custom_inplacevar(). This Python runner hook only accepts operator strings present in its IOPERATOR_TO_STR mapping and performs the operation via exec. An unrecognized operator string (custom opcodes, unusual operators, or a mismatched RestrictedPython version whose generated op string differs) raises this Exception. Note the message itself has a stray quote: "'{} is not supported inplace variable'".

Source

Thrown at redash/query_runner/python.py:177

    def custom_write(obj):
        """
        Custom hooks which controls the way objects/lists/tuples/dicts behave in
        RestrictedPython
        """
        return full_write_guard(obj)

    @staticmethod
    def custom_get_item(obj, key):
        return obj[key]

    @staticmethod
    def custom_get_iter(obj):
        return iter(obj)

    @staticmethod
    def custom_inplacevar(op, x, y):
        if op not in IOPERATOR_TO_STR.values():
            raise Exception("'{} is not supported inplace variable'".format(op))
        glb = {"x": x, "y": y}
        exec("x" + op + "y", glb)
        return glb["x"]

    @staticmethod
    def add_result_column(result, column_name, friendly_name, column_type):
        """Helper function to add columns inside a Python script running in Redash in an easier way

        Parameters:
        :result dict: The result dict
        :column_name string: Name of the column, which should be consisted of lowercase latin letters or underscore.
        :friendly_name string: Name of the column for display
        :column_type string: Type of the column. Check supported data types for details.
        """
        if column_type not in SUPPORTED_COLUMN_TYPES:
            raise Exception("'{0}' is not a supported column type".format(column_type))

        if "columns" not in result:

View on GitHub (pinned to ca79fe988d)

Solutions

1. Pin RestrictedPython to the version required by your Redash release (check requirements.txt) e.g. pip install RestrictedPython==<pinned>
2. If you maintain the codebase, extend IOPERATOR_TO_STR with the missing operator mapping
3. As a query author, replace augmented assignment with explicit form: x = x + y instead of x += y

Example fix

# before
x += 1
# after
x = x + 1

try:
    execute_python_query(code)
except Exception as e:
    if 'not supported inplace variable' in str(e):
        code = rewrite_augmented_assignments(code)  # x += 1 -> x = x + 1
        execute_python_query(code)

When it happens

Trigger: Executing a Python query with an augmented assignment whose operator token isn't in IOPERATOR_TO_STR — most commonly after upgrading RestrictedPython where the operator encoding changed, producing unknown op strings for ordinary code like x += 1.

Common situations: RestrictedPython version drift between the pinned version the runner was built for and an installed newer/older one; rarely, exotic operators (matrix @=) not in the mapping.

Related errors

• '{0}' is not configured as a supported import module
• '{0}' is not a supported column type
• Wrong data source name/id: %s.
• You do not have access to data source: %s.
• Query id %s does not exist.

AI-assisted analysis of getredash/redash@ca79fe988d (2026-08-28). Data as JSON: /api/errors/606af334b96a8fac. Report an issue: GitHub.