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Ambiguous project type extension

extension
A bare project.type name matched more than one extension contributing a project type.

Q-16-8 — Ambiguous project type extension

A bare project.type name matched more than one extension contributing a project type.

What this means

Extensions are identified by organization/name, but project.type accepts the bare name as a convenience. When two installed extensions contribute a project type with the same bare name, that convenience becomes ambiguous.

Quarto picks one and tells you which, rather than failing: the extension with no organization wins, and among organization-qualified candidates, the lexicographically first organization wins. The message names both the chosen extension and the ones it shadowed.

The render continues with the chosen type. The risk is that the choice is not the one you meant, and the resulting project is configured by the wrong extension — a failure that shows up as puzzling output rather than as an error.

Why this happens

  • Two extensions with a generic type name — docs, site, report — from different organizations.
  • A vendored copy alongside an installed one. An extension copied into _extensions/<name>/ while the same extension is also installed under _extensions/<org>/<name>/.
  • A fork. You forked an extension, installed the fork under your own organization, and left the original in place.

How to fix

Use the full organization/name form so the choice is explicit:

project:
  type: my-org/docs

This is worth doing even when the current default happens to be right — installing another extension later can change which candidate wins, and the bare form gives no signal when that happens.

If one of the candidates is a leftover, remove it:

quarto remove <owner>/<name>

or delete its directory under _extensions/.