OrchardCMS/OrchardCore · error · InvalidOperationException

Invalid dependency position of type

Error message

Invalid dependency position of type '{dependent.Type}' for resource '{dependent.Name}' positioned at '{dependent.Position}' depending on '{Name}' positioned at '{Position}'

What it means

RequireSettings.UpdatePositionFromDependent throws this InvalidOperationException when dependency ordering is contradictory: a resource required 'First' is positioned 'Last' while a resource that depends on it is positioned 'First' (Last cannot be reordered to satisfy a First-dependent). The dependency graph cannot be laid out in document order.

Solutions

Align the positions: require the dependency at First (or ByDependency) so a First-dependent can be satisfied.
Remove the explicit Last/First positioning on one of the two conflicting resources and let default ByDependency ordering apply.
Resolve which module/theme imposes the ordering and change it in that module's ResourceManifest or the RequireSettings call.
If you own both calls, drop the dependency or the positional constraint so ordering is unambiguous.

Example fix

// before
settings.BuildPosition(ResourcePosition.Last); // dependency required Last
required.BuildPosition(ResourcePosition.First); // dependent required First -> conflict
// after
settings.BuildPosition(ResourcePosition.ByDependency); // allow ordering by dependency

Defensive patterns

Strategy: validation

Validate before calling

if (dependent.Position == ResourcePosition.First && dependency.Position == ResourcePosition.Last)
    throw new InvalidOperationException("Cannot require a First-positioned resource that depends on a Last-positioned resource.");

Try / catch

try
{
    resourceManager.GetRequiredResources(resourceType);
}
catch (InvalidOperationException ex) when (ex.Message.Contains("Invalid dependency position"))
{
    logger.LogWarning(ex, "Conflicting resource positioning; using default ordering.");
}

Prevention

Only use First/Last positioning on leaf resources, not shared dependencies.
Let dependencies order themselves via ByDependency (the default).
Audit themes and modules that both position the same shared resource (e.g. jQuery).
Document positioning intent in one place (the manifest) rather than scattered Require calls.

When it happens

Trigger: Two resources where the dependent is required with ResourcePosition.First and the dependency is required with ResourcePosition.Last, via BuildPosition/CombinePosition during RequireSettings combination or dependency expansion.

Common situations: A theme requires a script 'at Foot/Last' while a module requires the same script 'at Head/First' and declares a dependency on it; conflicting positioning directives from two modules or a theme overriding module ordering for the same shared resource.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

AI-assisted analysis of OrchardCMS/OrchardCore@4306c0717f (2026-09-13). Data as JSON: /api/errors/eb057e30dcf8c29b. Report an issue: GitHub.

Appendix: source

Thrown at src/OrchardCore/OrchardCore.ResourceManagement.Abstractions/RequireSettings.cs:227

            return other._attributes == null ? null : new Dictionary<string, string>(other._attributes);
        }
        if (other._attributes == null)
        {
            return new Dictionary<string, string>(_attributes);
        }
        var mergedAttributes = new Dictionary<string, string>(_attributes);
        foreach (var pair in other._attributes)
        {
            mergedAttributes[pair.Key] = pair.Value;
        }
        return mergedAttributes;
    }

    public RequireSettings UpdatePositionFromDependent(RequireSettings dependent)
    {
        if (dependent.Position == ResourcePosition.First && Position == ResourcePosition.Last)
        {
            throw new InvalidOperationException($"Invalid dependency position of type '{dependent.Type}' for resource '{dependent.Name}' positioned at '{dependent.Position}' depending on '{Name}' positioned at '{Position}'");
        }

        // If a 'First' resource depends on a 'ByDependency' resource, position the dependency 'First'.
        if (dependent.Position == ResourcePosition.First && Position == ResourcePosition.ByDependency)
        {
            Position = ResourcePosition.First;
        }

        return this;
    }

    public RequireSettings UpdatePositionFromDependency(RequireSettings dependency)
    {
        // If a 'ByDependency' resource depends on a 'Last' resource, position the dependent 'Last'.
        if (Position == ResourcePosition.ByDependency && dependency.Position == ResourcePosition.Last)
        {
            Position = ResourcePosition.Last;
        }

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