database blocks are not supported by createDocTree templates

Error message

database blocks are not supported by createDocTree templates

What it means

createDocTree-style template rendering refuses to process a template whose parsed tree contains an attribute view (database) block. Database blocks have no plain-markdown rendering semantics in this code path, so rendering is aborted instead of producing a silently incomplete document tree. The check runs after parsing the template markdown via parseTemplateKTree and before walking nodes.

Source

Thrown at kernel/model/template_doc_tree_render.go:264

	contains := false
	ast.Walk(tree.Root, func(node *ast.Node, entering bool) ast.WalkStatus {
		if entering && ast.NodeAttributeView == node.Type {
			contains = true
			return ast.WalkStop
		}
		return ast.WalkContinue
	})
	return contains
}

func renderTemplateDocTreeMarkdown(markdown []byte, boxID string) (*parse.Tree, error) {
	tree, err := parseTemplateKTree(markdown)
	if err != nil {
		return nil, err
	}
	tree.Box = boxID
	if templateTreeContainsAttributeView(tree) {
		return nil, errors.New("database blocks are not supported by createDocTree templates")
	}

	var nodesNeedAppendChild, unlinks []*ast.Node
	blockIDs := map[string]string{}
	ast.Walk(tree.Root, func(node *ast.Node, entering bool) ast.WalkStatus {
		if !entering {
			return ast.WalkContinue
		}

		if "" != node.ID {
			oldID := node.ID
			node.ID = ast.NewNodeID()
			blockIDs[oldID] = node.ID
			node.SetIALAttr("id", node.ID)
			node.RemoveIALAttr(av.NodeAttrNameAvs)
			treenode.RefreshUpdated(node)
		}
		if (ast.NodeListItem == node.Type && (nil == node.FirstChild ||

View on GitHub (pinned to 8641553a1f)

Solutions

Remove the database/attribute-view block from the template markdown before rendering
Use a template without database blocks for createDocTree rendering
Render through a path that supports database blocks instead of the createDocTree template renderer

Example fix

// before: template.md contains a database block -> render fails
// after: strip the database block
markdown = removeDatabaseBlocks(markdown)
tree, err := renderTemplateDocTreeMarkdown(markdown, boxID, ...)

Defensive patterns

Strategy: validation

Validate before calling

func hasDatabaseBlock(markdown []byte) bool {
    engine := model.NewLute()
    tree := parse.Parse("", markdown, engine.ParseOptions)
    return tree != nil && model.TemplateTreeContainsAttributeView(tree)
}
// call renderTemplateDocTreeMarkdown only if !hasDatabaseBlock(md)

Prevention

Keep createDocTree templates free of database/attribute-view blocks
Check templates with templateTreeContainsAttributeView before rendering
Regenerate templates from documents without embedded databases

When it happens

Trigger: renderTemplateDocTreeMarkdown is called with markdown containing a database/attribute-view block (e.g. a template saved from a document that embeds an attribute view); templateTreeContainsAttributeView returns true and the error is returned to the createDocTree template renderer.

Common situations: Users save a document that contains a database block as a template and then use it in a createDocTree flow; templates copied from other documents with embedded databases; older templates that gained database blocks after an upgrade.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of siyuan-note/siyuan@8641553a1f (2026-09-11). Data as JSON: /api/errors/9230cb488be08100. Report an issue: GitHub.