Remote repository links

Documenter, if set up appropriately, can automatically generate links to publicly hosted Git repositories (such as source and edit links to e.g. repositories hosted on GitHub). Usually this is for linking back to the main package repository or the project source code.

The Remotes API is used to specify remote repositories and generate the URLs. It is also designed to be extended, to support additional Git repository hosting services.

Remote link types

There are two categories of remote repositories that (may) need to be configured for Documenter to be able to determine remote URLs:

1. Project repository remote, specified with the repo keyword to makedocs. This refers to the project as a whole (rather than specific files), and is used for the repository landing page link, issue references etc.

2. File link remotes, specified by the remotes keyword to makedocs. These are used to link a file system file to the corresponding file in the remote repository. In particular, these are used to generate the edit links for manual pages, and Julia source file links for docstrings.

For the most common case – a repository of a simple Julia package – there is usually only one remote repository that one links to, and the distinction between file links and repository links is not relevant. However, in more complex setups it may be necessary to distinguish between the two cases. The defaults to the two keywords try to cater for the most common use case, and as is explained below, this means that there has to be some interaction between these two arguments.

Remotes for files

When Documenter has to determine the URL of a file in the hosted repository, it gets a local filesystem absolute path as an input.^[1] In the case of Markdown files, those local paths are determined by makedocs when it reads them. The links to Julia files are determined from the docsystem, and point to where the code was loaded from (e.g. for a development dependency of the environment, they come from the Pkg.developed path; but for normal Pkg.add dependencies the source files are usually in ~/.julia/packages).

In most cases, for both Markdown and Julia files, the files Documenter is concerned about are located in the currently checked out Git repository that contains the Documenter make.jl script (e.g. the locally checked out package repository). However, sometimes they may also be in a different repository (either in a subdirectory of or outside of the primary repository), or even in a non-Git directory outside of the primary repository (e.g. if you're trying to build the documentation of a release tarball).

To handle those cases, the remotes keyword to makedocs can be used to set up a local directory => remote repository mapping for local file system paths. The local directory is assumed to correspond to the root of the Git repository, and any subpath within that directory is then resolved to the corresponding path in the remote repository. If there are nested remotes configured, Documenter will use the one that matches first as it walks up the directory tree from the original path.

As the common cases are a locally checked out Git repository (added with Pkg.develop to the docs environment), or a released package which is hosted on GitHub (Pkg.added to the environment), Documenter will also try to determine such remotes automatically.

• When Documenter walks up the directory tree, it checks whether the directory is a root of a Git repository (by looking for the presence of a .git directory or file). Once it finds a valid local repository root, it tries to read its origin remote URL.
  • If that matches a GitHub repository^[2], Documenter automatically sets up a mapping from that directory, and then uses that to determine the remote URLs.
  • If Documenter is unable to determine the remote from the repository's origin (e.g. origin is not set up, or it is hosted somewhere else), it will error, as it will not be able to determine the remote URLs. In this case, the remote should be configured explicitly with remotes.

You can think of it as Documenter automatically populating remotes with any cloned GitHub repositories it finds.^[3]

For released packages (those added using Pkg.add(...) rather than Pkg.develop(...)), the version and repository can be determined from the package metadata, but a commit hash is not readily available. In this case, Documenter will guess that a tag v$VERSION exists in the repository on GitHub. Note that these tags are created automatically by the widely used JuliaRegistries/TagBot action. Since this is sometimes not the case, and could cause dead or incorrect links, setting the linkcheck keyword to true to makedocs will check these guessed links have an existing target and that the existing target matches the published package. (Note this will also all other external links from your documentation.) Note that enabling this option can cause documentation builds to fail due to network errors or intermittent downtime of external services.

repo & remotes interaction

Since Documenter is primarily used to generate documentation for Julia packages, there is some interaction between the repo and remotes keyword arguments, to automagically determine their defaults. This means that usually it is not necessary to specify either explicitly in the make.jl script.

The rules are as follows:

• If repo is not specified, it is essentially determined like any other remote link, by trying to figure out the repository that contains the root path argument of makedocs (defaulting to the directory of the make.jl script; usually the docs/ directory). The Remote object will one of the remotes, which in turn may have been determined automatically via the origin URL of the containing Git repository.

• If repo is specified, but the remotes for the repository root is not, repo will function as a remotes entry for the repository root. This is so that it would not be necessary to specify the same argument twice (i.e. once for general repository links, once for file links).

• If both repo and a remotes for the repository root are configured, Documenter will throw an error, as it does not really make sense for them to point to two different remotes.^[4]

Remotes API

GitHub(user :: AbstractString, repo :: AbstractString)
GitHub(remote :: AbstractString)

makedocs(
    repo = GitHub("JuliaDocs", "Documenter.jl")
)

GitLab(host, user, repo)
GitLab(user, repo)
GitLab(remote)

makedocs(
    repo = GitLab("JuliaDocs", "Documenter.jl")
)

The following types and functions and relevant when creating custom Remote types:

abstract type Remote

Remotes.repourl(remote::T) -> String

Remotes.fileurl(remote::T, ref, filename, linerange) -> String

Remotes.issueurl(remote::T, issuenumber)