From 50c4e677557ef21d6ccf83869d341af73a91e6a1 Mon Sep 17 00:00:00 2001
From: Fredrik Ekre <ekrefredrik@gmail.com>
Date: Thu, 30 Jul 2020 19:53:19 +0200
Subject: [PATCH 1/2] rc docs: strip extra pre-release info, deploy to e.g.
 1.5.0-rc2 instead of 1.5.0-rc2.0

---
 doc/make.jl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/doc/make.jl b/doc/make.jl
index 112dbcae63126..47466374daeff 100644
--- a/doc/make.jl
+++ b/doc/make.jl
@@ -221,7 +221,10 @@ struct BuildBotConfig <: Documenter.DeployConfig end
 function Documenter.deploy_folder(::BuildBotConfig; devurl, kwargs...)
     haskey(ENV, "DOCUMENTER_KEY") || return nothing
     if Base.GIT_VERSION_INFO.tagged_commit
-        return "v$(Base.VERSION)"
+        # Strip extra pre-release info (1.5.0-rc2.0 -> 1.5.0-rc2)
+        ver = VersionNumber(VERSION.major, VERSION.minor, VERSION.patch,
+            isempty(VERSION.prerelease) ? () : (VERSION.prerelease[1],))
+        return "v$(ver)"
     elseif Base.GIT_VERSION_INFO.branch == "master"
         return devurl
     end

From cd4330d9b0b87cfa901fadbddce91069aa32f79e Mon Sep 17 00:00:00 2001
From: Fredrik Ekre <ekrefredrik@gmail.com>
Date: Thu, 30 Jul 2020 19:53:54 +0200
Subject: [PATCH 2/2] rc docs: hack Documenter to insert rc docs in the version
 selector.

---
 doc/make.jl | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/doc/make.jl b/doc/make.jl
index 47466374daeff..1d7ac1615deb1 100644
--- a/doc/make.jl
+++ b/doc/make.jl
@@ -233,11 +233,33 @@ end
 
 const devurl = "v$(VERSION.major).$(VERSION.minor)-dev"
 
+# Hack to make rc docs visible in the version selector
+struct Versions versions end
+function Documenter.Writers.HTMLWriter.expand_versions(dir::String, v::Versions)
+    # Find all available docs
+    available_folders = readdir(dir)
+    cd(() -> filter!(!islink, available_folders), dir)
+    filter!(x -> occursin(Base.VERSION_REGEX, x), available_folders)
+
+    # Look for docs for an "active" release candidate and insert it
+    vnums = [VersionNumber(x) for x in available_folders]
+    master_version = maximum(vnums)
+    filter!(x -> x.major == 1 && x.minor == master_version.minor-1, vnums)
+    rc = maximum(vnums)
+    if !isempty(rc.prerelease) && occursin(r"^rc", rc.prerelease[1])
+        src = "v$(rc)"
+        @assert src ∈ available_folders
+        push!(v.versions, src => src, pop!(v.versions))
+    end
+
+    return Documenter.Writers.HTMLWriter.expand_versions(dir, v.versions)
+end
+
 deploydocs(
     repo = "github.com/JuliaLang/docs.julialang.org.git",
     deploy_config = BuildBotConfig(),
     target = joinpath(buildroot, "doc", "_build", "html", "en"),
     dirname = "en",
     devurl = devurl,
-    versions = ["v#.#", devurl => devurl]
+    versions = Versions(["v#.#", devurl => devurl]),
 )