The project.refs file

If one has elected to store source references in a single project.refs file, then it will be stored at the toplevel of your project directory adjacent to project.conf. This can be configured in your project using the ref-storage configuration

Sources for junction elements are stored separately in an adjacent junction.refs file of the same format.

Basic behavior

When a project.refs file is in use, any source references found in the inline source declarations are considered invalid and will be ignored, and a warning will be emitted for them.

When bst track is run for your project, the project.refs file will be updated instead of the inline source declarations. In the absence of a project.refs file, bst track will create one automatically with the tracking results.

An interesting property of project.refs is that it allows for cross junction tracking. This is to say that it is possible to override the ref of a given source in a project that your project depends on via a junction, without actually modifying the junctioned project.


The project.refs uses the same YAML format used throughout BuildStream, and supports the same directives which apply to project.conf and element declaration files (i.e. element.bst files).

The project.refs file format itself is very simple, it contains a single projects key at the toplevel, which is a dictionary of project names. Each project name is a dictionary of element names, and each element name holds a list of dictionaries corresponding to the element’s sources.


# Main toplevel "projects" key

  # The local project's name is "core"

    # A dictionary of element names

    # A list of sources corresponding to the element
    # in the same order in which they were declared.
    # The values of this list are dictionaries of the
    # symbolic "ref" portion understood by the given
    # source plugin implementation.
    - ref: af6ba39142220687c500f79b4aa2f181d9b24e4...

  # The "core" project depends on the "bootstrap" project,
  # here we are allowed to override the refs for the projects
  # we depend on through junctions.

    - ref: 4ff941449631ace0d4d203e3483be9dbc9da4540...