Skip creating artifact update PR when up-to-date (#22)

* Skip creating artifact update PR when up-to-date

* Add keepalive job

.github/workflows/Release.yaml

@@ -1,3 +1,4 @@
+---
 name: Release
 on:
  push:

.github/workflows/Update.yaml

@@ -1,6 +1,14 @@
 ---
+# Automatically builds new TZJData artifacts and creates a PR with the associated
+# changes to the `Project.toml` and `Artifacts.toml`. Once the PR has been merged the
+# `Release.yaml` workflow will generate a GitHub release with the assets to fufill the
+# artifact URLs within the `Artifacts.toml`.
+
 name: Update
 on:
+ pull_request:
+ paths:
+ - .github/workflows/Update.yaml
  schedule:
  - cron: "44 9 * * *" # Every day at 09:44 UTC
  workflow_dispatch: {}
@@ -18,7 +26,7 @@ jobs:
  steps:
  - uses: actions/checkout@v4
  with:
- ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || 'main' }}
+ ref: ${{ github.event.pull_request.head.sha || 'main' }}
  - uses: julia-actions/setup-julia@v1
  with:
  version: "1"
@@ -33,25 +41,34 @@ jobs:
  shell: julia --color=yes {0}
  run: |
  include(joinpath(pwd(), "gen", "make.jl"))
- (; tarball_path, tarball_sha256, new_version, commit_message) = update_tzdata()
- key = basename(tarball_path) * "-" * tarball_sha256
- @show key tarball_path commit_message
- open(ENV["GITHUB_OUTPUT"], "a") do io
- println(io, "key=$key")
- println(io, "tarball_path=$tarball_path")
- println(io, "commit_message=$commit_message")
+ if is_pkg_tzdata_version_outdated()
+ (; tarball_path, tarball_sha256, new_version, commit_message) = update_tzdata()
+ key = basename(tarball_path) * "-" * tarball_sha256
+ @show key tarball_path commit_message
+ open(ENV["GITHUB_OUTPUT"], "a") do io
+ println(io, "updated=true")
+ println(io, "key=$key")
+ println(io, "tarball_path=$tarball_path")
+ println(io, "commit_message=$commit_message")
+ end
+ else
+ open(ENV["GITHUB_OUTPUT"], "a") do io
+ println(io, "updated=false")
+ end
  end
  println("workflow_ref=${{ github.workflow_ref }}")
  - run: git diff
  # Store the Julia artifact tarball as a GitHub actions artifact. This will allow us to retrieve this
  # tarball from other workflows.
  - uses: actions/upload-artifact@v4
+ if: ${{ steps.build.outputs.updated == 'true' }}
  id: action-artifact
  with:
  name: ${{ steps.build.outputs.key }}
  path: ${{ steps.build.outputs.tarball_path }}
  - name: Create Pull Request
  uses: peter-evans/create-pull-request@v5
+ if: ${{ steps.build.outputs.updated == 'true' }}
  with:
  base: main # Shouldn't be required for `workflow_dispatch`
  title: ${{ steps.build.outputs.commit_message }}
@@ -62,5 +79,18 @@ jobs:
  Artifacts.toml
  commit-message: ${{ steps.build.outputs.commit_message }}
  branch: gh/update-tzdata
- delete-branch: ${{ github.event_name == 'pull_request' }}
  token: ${{ secrets.TZJDATA_UPDATE_TOKEN }} # TODO: Fine-grained token expires
+
+ # Work around having GitHub suspend the scheduled workflow if there is no commit activity
+ # for the past 60 days. As this repo doesn't get much activity beyond artifact updates
+ # this can be quite annoying.
+ keepalive:
+ name: Keepalive
+ runs-on: ubuntu-latest
+ # These permissions are needed to:
+ # - Keep the workflow alive: https://github.com/marketplace/actions/keepalive-workflow#github-api-keepalive-workflow---default-for-github-actions-users
+ permissions:
+ actions: write
+ steps:
+ - uses: actions/checkout@v4
+ - uses: gautamkrishnar/keepalive-workflow@v2

gen/make.jl

@@ -109,7 +109,29 @@ function upload_to_github_release(owner, repo_name, commit, tag, path; token=ENV
  run(cmd)
 end
 
-function update_tzdata()
+function next_tzdata_version(tzdata_version::AbstractString)
+ # Always fetch the current list of tzdata versions (ignoring any caching).
+ tzdata_versions = TZData.tzdata_versions()
+ i = findfirst(==(tzdata_version), tzdata_versions)
+ if !isnothing(i)
+ return i < length(tzdata_versions) ? tzdata_versions[i + 1] : nothing
+ else
+ error("Unable to locate tzdata version $tzdata_version in list of tzdata versions")
+ end
+end
+
+function is_pkg_tzdata_version_outdated()
+ repo_path = joinpath(@__DIR__, "..")
+
+ # Read Project.toml
+ project_toml = joinpath(repo_path, "Project.toml")
+ project = read_project(project_toml)
+ tzdata_version = only(project.version.build)
+
+ return !isnothing(next_tzdata_version(tzdata_version))
+end
+
+function update_tzdata(; force::Bool=false)
  repo_path = joinpath(@__DIR__, "..")
  pkg_url = remote_url(repo_path)
 
@@ -119,14 +141,13 @@ function update_tzdata()
  old_version = project.version
  old_tzdata_version = only(old_version.build)
 
- # Always fetch the current list of tzdata versions (ignoring any caching).
- tzdata_versions = TZData.tzdata_versions()
- i = findfirst(==(old_tzdata_version), tzdata_versions)
- if i == length(tzdata_versions)
- new_tzdata_version = tzdata_versions[i]
+ # If `old_tzdata_version` is already the latest version then `nothing` will be returned
+ # so we'll perform a rebuild of the current tzdata version.
+ new_tzdata_version = next_tzdata_version(old_tzdata_version)
+ if isnothing(new_tzdata_version)
+ new_tzdata_version = tzdata_version
  new_version = Base.nextpatch(old_version)
  else
- new_tzdata_version = tzdata_versions[i + 1]
  new_version = Base.nextminor(old_version)
  end