Pretend to be PR events to deploy previews.

Author: fredrikekre

.github/workflows/ci.yml

@@ -4,7 +4,7 @@ on:
   push:
     branches:
       - 'master'
-      - 'create-pull-request/patch'
+      - 'create-pull-request/package-update'
     tags: '*'
   pull_request:
 

.github/workflows/pkg-update.yml

@@ -27,6 +27,7 @@ jobs:
         uses: peter-evans/create-pull-request@v3
         with:
           title: 'Automatic Pkg.update()'
+          branch: 'create-pull-request/package-update'
           author: 'GitHub <noreply@github.com>'
           body: |
             Automatic `Pkg.update()` with the following changes:

make.jl

@@ -97,8 +97,25 @@ makedocs(
     ),
 )
 
-deploydocs(
-    versions = nothing,
-    push_preview = true,
-    repo = "github.com/JuliaLogging/julialogging.github.io.git",
-)
+# Hack to deploy preview builds from package auto-update
+# This is necessary since when using the create-pull-request action, the PR is opened
+# by the github-actions user authenticating with the default GITHUB_TOKEN, which also
+# means that regular CI will not be triggered. This is circumvented by using a SSH key
+# with the actions/checkout action when cloning, which means that the resulting commit
+# is pushed with the same SSH key triggering a "push" event build. However, Documenter
+# only builds previews for the "pull_request" event type, so we need to pretend to be
+# a "pull_request" event type by temporarily setting some environment variables.
+env = Dict{String,String}()
+if ENV["GITHUB_EVENT_NAME"] == "push" &&
+   ENV["GITHUB_REF"] == "refs/heads/create-pull-request/package-update"
+    env["GITHUB_EVENT_NAME"] = "pull_request"
+    env["GITHUB_REF"] = "refs/pull/1234/merge"
+end
+
+withenv(env...) do
+    deploydocs(
+        versions = nothing,
+        push_preview = true,
+        repo = "github.com/JuliaLogging/julialogging.github.io.git",
+    )
+end