gohugoio/hugo · error

failed to add internal partial decorator template %q: %w

Error message

failed to add internal partial decorator template %q: %w

What it means

After inserting the decorator template info, Hugo sets its parse tree via store.addTransformedTemplateSetTree (templatetransform.go:352-355). If assigning the cloned inner node list to the template's tree fails, the error is wrapped with the internal decorator name. This is an internal step in synthesizing the partial decorator.

Source

Thrown at tpl/tplimpl/templatetransform.go:354

	internalPartialName := fmt.Sprintf("_partials/%s%s", PartialDecoratorPrefix, innerHash)

	if c.lookupFn(internalPartialName, c.t) == nil {
		innerCopy := withNode.List.CopyList()
		ti, err := c.store.addTransformedTemplateInsert(internalPartialName, SubCategoryInline)
		if err != nil {
			c.err = fmt.Errorf("failed to create internal partial decorator template %q: %w", internalPartialName, err)
			return
		}
		if ti == nil {
			c.err = fmt.Errorf("failed to find internal partial decorator template %q after insertion", internalPartialName)
			return
		}

		cc := newTemplateTransformContext(ti, c.store, c.lookupFn)

		tree, err := c.store.addTransformedTemplateSetTree(ti, innerCopy)
		if err != nil {
			c.err = fmt.Errorf("failed to add internal partial decorator template %q: %w", internalPartialName, err)
			return
		}

		if err := cc.applyTransformationsAndSetReturnWrapper(tree); err != nil {
			c.err = fmt.Errorf("failed to transform internal partial decorator template %q: %w", internalPartialName, err)
			return
		}

	}

	newInner := popPartialDecorator.CopyList()
	ifNode := newInner.Nodes[0].(*parse.IfNode)

	placeholderPipe := ifNode.Pipe.Cmds[0].Args[0].(*parse.PipeNode)

	// Set PLACEHOLDER1 to the unique ID for this partial decorator.
	sn1 := placeholderPipe.Cmds[0].Args[1].(*parse.PipeNode).Cmds[0].Args[0].(*parse.StringNode)
	sn1.Text = innerHash

View on GitHub (pinned to 52c9bd7908)

Solutions

1. Inspect the wrapped error for the underlying cause.
2. Simplify the with-partial template to isolate the trigger.
3. Report as a Hugo bug with a reproducer if it occurs on stock Hugo.
4. Update Hugo.

// Surface the wrapped cause during diagnosis:
if err != nil && strings.Contains(err.Error(), "failed to add internal partial decorator template") {
    log.Fatalf("decorator tree set failed: %v", err)
}

When it happens

Trigger: Failure inside addTransformedTemplateSetTree when assigning the deferred/inner node list to the synthesized decorator template. Triggered during the transform of a with-partial block.

Common situations: Rare internal failure; may indicate a template-name collision or a parse-tree assignment problem in a custom Hugo build or an edge-case template.

Related errors

• failed to create internal partial decorator template %q: %w
• failed to transform internal partial decorator template %q:
• inner cannot be used inside a with block that wraps a partia
• failed to find internal partial decorator template %q after
• maximum template call stack size exceeded in %q

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/64b6bf3e68be869e. Report an issue: GitHub.