feat: refine changelog creation for releases

.github/workflows/compile-changelog.rb

@@ -0,0 +1,77 @@
+
+# This script identifies the commits that have been made to the current
+# branch since the release before this branch. It formats them according
+# to a format specifier.
+#
+# Usage:
+#   compile-changelog outfile
+#
+#   outfile: the file location to write the changelog to
+
+module Git
+  def self.one_line_format(repository_url)
+    "[<code>%h</code>](#{repository_url}/commit/%h) %s (%an)"
+  end
+
+  def self.current_branch
+    `git rev-parse --abbrev-ref HEAD`.strip
+  end
+
+  def self.default_branch
+    `git rev-parse --abbrev-ref origin/HEAD`.strip
+  end
+
+  def self.default_branch_head
+    `git rev-parse origin/HEAD`.strip
+  end
+
+  def self.initial_commit
+    `git rev-list --max-parents=0 #{default_branch}`.strip
+  end
+
+  def self.release_branches
+    `git branch --list -r origin/release/*`.split("\n").map(&:strip)
+  end
+
+  def self.commit_date(commit)
+    `git show -s --format=%ct #{commit}`.strip
+  end
+
+  def self.merge_base_from(branch1, branch2)
+    `git merge-base #{branch1} #{branch2}`.strip
+  end
+
+  # Returns the commit where the given branch forked from the default git branch.
+  # If the given branch is the default git branch, the branch commit is the initial
+  # commit in the repo.
+  def self.merge_base(branch)
+    if branch == Git::default_branch_head
+      Git::initial_commit()
+    else
+      Git::merge_base_from(Git::default_branch, branch)
+    end
+  end
+
+  def self.formatted_commits_between(low, high, format)
+    `git log --pretty="format:#{format}" --no-merges #{low}..#{high}`
+  end
+end
+
+outfile = ARGV[0]
+repository_url = "https://github.com/#{ENV['GITHUB_REPOSITORY']}"
+commit_upper_bound = Git::current_branch
+commit_lower_bound = Git::release_branches
+                      .map     { |branch| Git::merge_base(branch) }
+                      .reject  { |commit| Git::commit_date(commit) >= Git::commit_date(commit_upper_bound) }
+                      .sort_by { |commit| Git::commit_date(commit) }
+                      .reverse
+                      .first
+
+changelog = Git::formatted_commits_between(
+  commit_lower_bound || Git::initial_commit,
+  commit_upper_bound,
+  Git::one_line_format(repository_url))
+
+File.open(outfile, 'a') do |file|
+  file.puts changelog
+end

.github/workflows/on-main-branch-change.yaml

@@ -0,0 +1,46 @@
+# Creates or updates a 'prerelease' release whenever main is
+# changed. Attaches a built PDF to that release.
+name: On Main Branch Change
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build_draft_pdf:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Git repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set origin HEAD
+        run: git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
+
+      - name: Compile document
+        uses: xu-cheng/latex-action@v2
+        with:
+          root_file: ifc.tex
+          working_directory: ltx
+
+      - name: Compile changelog
+        run: |
+          echo 'CHANGELOG<<EOF' >> $GITHUB_ENV
+          ruby ./.github/workflows/compile-changelog.rb $GITHUB_ENV
+          echo 'EOF' >> $GITHUB_ENV
+
+      - name: Create prerelease
+        uses: ncipollo/release-action@v1
+        with:
+          token: "${{ secrets.GITHUB_TOKEN }}"
+          allowUpdates: true
+          name: Prerelease
+          prerelease: true
+          tag: prerelease
+          body: |
+            This release is a prerelease. The contents of this release are likely to change.
+            # Changelog
+            ${{ env.CHANGELOG }}
+          artifacts: |
+            ltx/ifc.pdf

.github/workflows/on-release-branch-change.yml

@@ -0,0 +1,50 @@
+# Creates or updates a release's generated PDF when a change occurs
+# to a release branch
+name: On Release Branch Change
+on:
+  push:
+    branches:
+      - "release/*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Git repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set origin HEAD
+        run: git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
+
+      - name: Extract branch name
+        shell: bash
+        run: echo "RELEASE_NAME=$(echo ${GITHUB_REF#refs/heads/release/})" >> $GITHUB_ENV
+
+      - name: Compile document
+        uses: xu-cheng/latex-action@v2
+        with:
+          root_file: ifc.tex
+          working_directory: ltx
+
+      - name: Compile changelog
+        run: |
+          echo 'CHANGELOG<<EOF' >> $GITHUB_ENV
+          ruby ./.github/workflows/compile-changelog.rb $GITHUB_ENV
+          echo 'EOF' >> $GITHUB_ENV
+
+      - name: Update release
+        uses: ncipollo/release-action@v1
+        with:
+          token: "${{ secrets.GITHUB_TOKEN }}"
+          allowUpdates: true
+          name: ${{ env.RELEASE_NAME }}
+          prerelease: false
+          tag: ${{ env.RELEASE_NAME }}
+          body: |
+            # Changelog
+            ${{ env.CHANGELOG }}
+          artifacts: |
+            ltx/ifc.pdf
+

.github/workflows/on-release-created.yml

@@ -0,0 +1,37 @@
+# Creates a release branch whenever a release is created.
+
+name: On Release Created
+on:
+  release:
+    types:
+      - published
+
+jobs:
+  create_branch:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: peterjgrainger/action-create-branch@v2.0.1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          branch: 'release/${{ github.event.release.tag_name }}'
+
+  build_latex:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Git repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Compile document
+        uses: xu-cheng/latex-action@v2
+        with:
+          root_file: ifc.tex
+          working_directory: ltx
+
+      - name: Add PDF to Release
+        uses: softprops/action-gh-release@v0.1.13
+        if: startsWith(github.ref, 'refs/tags/')
+        with:
+          files: ltx/ifc.pdf