langgenius/dify · error · ValueError

Unsupported environment variable value type: {value_type}

Error message

Unsupported environment variable value type: {value_type}

What it means

Raised by _serialize_environment_variable when a dict-form environment variable's value_type maps (via SegmentType(...).exposed_type()) to a type not in ENVIRONMENT_VARIABLE_SUPPORTED_TYPES (api/controllers/console/app/workflow.py:555-557). The serializer refuses to emit unsupported value types to keep the draft/workflow contract stable. Note the message interpolates the resolved exposed type, not the raw string.

Source

Thrown at api/controllers/console/app/workflow.py:557

            return {
                "id": value.id,
                "name": value.name,
                "value": value.value,
                "value_type": str(value.value_type.exposed_type()),
                "description": value.description,
            }

        case dict():
            value_type_str = value.get("value_type")
            if not isinstance(value_type_str, str):
                raise TypeError(
                    f"unexpected type for value_type field, value={value_type_str}, type={type(value_type_str)}"
                )
            if value_type_str == LLM_ENVIRONMENT_VARIABLE_VALUE_TYPE:
                return value
            value_type = SegmentType(value_type_str).exposed_type()
            if value_type not in ENVIRONMENT_VARIABLE_SUPPORTED_TYPES:
                raise ValueError(f"Unsupported environment variable value type: {value_type}")
            return value

        case _:
            return value


@console_ns.route("/apps/<uuid:app_id>/workflows/draft")
class DraftWorkflowApi(Resource):
    @console_ns.doc("get_draft_workflow")
    @console_ns.doc(description="Get draft workflow for an application")
    @console_ns.doc(params={"app_id": "Application ID"})
    @console_ns.response(
        200,
        "Draft workflow retrieved successfully",
        console_ns.models[WorkflowResponse.__name__],
    )
    @console_ns.response(404, "Draft workflow not found")
    @setup_required

View on GitHub (pinned to ef8544b173)

Solutions

1. Use only value_type values backed by ENVIRONMENT_VARIABLE_SUPPORTED_TYPES (string, number, bool, object, array[string], etc.).
2. If a new type is genuinely needed, extend ENVIRONMENT_VARIABLE_SUPPORTED_TYPES and SegmentType support together.
3. Align client and backend versions so the client only sends types the backend recognizes.
4. Inspect the rejected variable's value_type in the request payload and replace it with a supported equivalent.

Example fix

// before: unsupported value type
{value_type: 'file', value: ...}
// after: use a supported type (e.g. string url)
{value_type: 'string', value: 'https://...'}

// Restrict value_type to the backend allowlist before submit
const ALLOWED = ['string','number','bool','object','array[string]','array[number]','array[object]']
vars.forEach(v => { if (!ALLOWED.includes(v.value_type)) v.value_type = 'string' })

const ALLOWED = new Set(['string','number','bool','object','array[string]','array[number]','array[object]'])
function isSupportedType(t) { return typeof t === 'string' && ALLOWED.has(t) }

When it happens

Trigger: Syncing a draft workflow whose environment_variables (or conversation_variables routed through the same serializer) include a value_type that resolves to an unsupported SegmentType exposed type. Bypasses front-end type lists and submits a raw type string.

Common situations: Front-end sending a new/custom value type before the backend allowlist (ENVIRONMENT_VARIABLE_SUPPORTED_TYPES) was extended; payload tampering; version skew between a newer client and an older backend that lacks the new type; import from an external graph format with foreign type names.

Related errors

• patched environment variables require an id
• patched environment variable ids must be unique
• deleted environment variable ids must not be empty
• deleted environment variable ids must be unique
• an environment variable cannot be upserted and deleted in th

AI-assisted analysis of langgenius/dify@ef8544b173 (2026-08-12). Data as JSON: /api/errors/5bd35d3594cd49fa. Report an issue: GitHub.