legacy customization arg %q clear default address: %w

Error message

legacy customization arg %q clear default address: %w

What it means

Wraps a failure from the dagql Select calling `__withDefaultAddress` with an empty string, used to clear any existing default address when a legacy DefaultPath is being set (core/module.go:707). Legacy semantics made defaultPath and defaultAddress mutually exclusive.

Source

Thrown at core/module.go:707

				if err := dag.Select(ctx, updatedArg, &updatedArg, dagql.Selector{
					Field: "__withDefaultValue",
					Args:  []dagql.NamedInput{{Name: "defaultValue", Value: jsonValue}},
				}); err != nil {
					return updatedArg, fmt.Errorf("legacy customization arg %q default value: %w", argSelf.Name, err)
				}
			}
			if cust.DefaultPath != "" {
				if err := dag.Select(ctx, updatedArg, &updatedArg, dagql.Selector{
					Field: "__withDefaultPath",
					Args:  []dagql.NamedInput{{Name: "defaultPath", Value: dagql.String(cust.DefaultPath)}},
				}); err != nil {
					return updatedArg, fmt.Errorf("legacy customization arg %q default path: %w", argSelf.Name, err)
				}
				if err := dag.Select(ctx, updatedArg, &updatedArg, dagql.Selector{
					Field: "__withDefaultAddress",
					Args:  []dagql.NamedInput{{Name: "defaultAddress", Value: dagql.String("")}},
				}); err != nil {
					return updatedArg, fmt.Errorf("legacy customization arg %q clear default address: %w", argSelf.Name, err)
				}
			}
			if cust.DefaultAddress != "" {
				if err := dag.Select(ctx, updatedArg, &updatedArg, dagql.Selector{
					Field: "__withDefaultAddress",
					Args:  []dagql.NamedInput{{Name: "defaultAddress", Value: dagql.String(cust.DefaultAddress)}},
				}); err != nil {
					return updatedArg, fmt.Errorf("legacy customization arg %q default address: %w", argSelf.Name, err)
				}
				if err := dag.Select(ctx, updatedArg, &updatedArg, dagql.Selector{
					Field: "__withDefaultPath",
					Args:  []dagql.NamedInput{{Name: "defaultPath", Value: dagql.String("")}},
				}); err != nil {
					return updatedArg, fmt.Errorf("legacy customization arg %q clear default path: %w", argSelf.Name, err)
				}
			}
			if len(cust.Ignore) > 0 {
				if err := dag.Select(ctx, updatedArg, &updatedArg, dagql.Selector{

View on GitHub (pinned to 82ba2681db)

Solutions

Update the module SDK/codegen so the mutual-exclusion semantics are handled natively.
Set only one of DefaultPath or DefaultAddress in the customization, not a transition between them.
Confirm the argument is a service-address-compatible type before touching defaultAddress.
Reload module and retry if the engine error was transient.

Defensive patterns

Strategy: try-catch

Try / catch

if err := loadModule(ctx); err != nil {
  if strings.Contains(err.Error(), "clear default address") {
    // update SDK so legacy path/address mutual exclusion is handled natively
  }
}

Prevention

Set only one of defaultPath/defaultAddress per argument
Use current SDK APIs instead of legacy customizations
Test module loads after engine upgrades

When it happens

Trigger: After applying DefaultPath, the clear-address select fails — the argument TypeDef doesn't support `__withDefaultAddress` (wrong type kind) or the query errored.

Common situations: Legacy modules with directory-type arguments transitioning from a defaultAddress to a defaultPath; version-skew between engine and module SDK.

Related errors

AI-assisted analysis of dagger/dagger@82ba2681db (2026-09-05). Data as JSON: /api/errors/df8ff3cc5a927dda. Report an issue: GitHub.