CI: Add release workflow

This github actions workflow will create a draft release for PRs that
updates the version file.

The commit message subject line must be
Release microcom <version>

The commit message body will be used as release description. The release
is converted from draft to an actual release, and the commit thereby
tagged once the PR is merged.

Signed-off-by: Jonas Rebmann <[email protected]>

Author: jonrebm

.github/workflows/build.yml

@@ -1,4 +1,3 @@
----
 name: Build test
 on:
   push:

.github/workflows/release-pr.yml

@@ -0,0 +1,101 @@
+name: Draft Release
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, closed]
+    paths:
+      - VERSION
+    branches: [main]
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  validate-release-commit:
+    if: >
+      !(github.event.pull_request.merged == true &&
+        !contains(join(github.event.pull_request.labels.*.name), 'release'))
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout merge
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Get release commit info
+        id: version
+        run: |
+          ver=$(cat VERSION)
+          if ! echo "$ver" | grep -Eq '^[0-9]{4}\.[0-9]{2}\.[0-9]+$'; then
+            echo "Invalid version format: $ver"
+            exit 1
+          fi
+
+          echo "version=$ver" >> $GITHUB_OUTPUT
+
+          headline="$(git show --format=%s ${{github.event.pull_request.head.sha}})"
+          if ! echo "$headline" | grep -Eq "^[Rr]elease microcom $ver$"; then
+            echo "Invalid commit headline: $headline"
+            exit 1
+          fi
+
+          body="$(
+            git show -s --format=%b ${{github.event.pull_request.head.sha}} \
+            | sed -E '/^Signed-off-by: /d'
+          )"
+
+          echo 'body<<EOF' >> $GITHUB_OUTPUT
+          echo "$body" >> $GITHUB_OUTPUT
+          echo 'EOF' >> $GITHUB_OUTPUT
+
+      - name: Install Dependencies
+        run: sudo apt install -y libreadline6-dev autoconf automake
+
+      - name: Build release packages
+        run: |
+          autoreconf -i
+          ./configure
+          make dist
+
+      # DRAFT release on pr creation and update
+      - name: Create or update release draft
+        if: github.event.pull_request.merged == false
+        uses: softprops/action-gh-release@v2
+        with:
+          draft: true
+          tag_name: v${{steps.version.outputs.version}}
+          name: microcom ${{steps.version.outputs.version}}
+          body: ${{steps.version.outputs.body}}
+          files: |
+            microcom-*.tar.gz
+            microcom-*.tar.xz
+
+      # PUBLISH release on merge
+      - name: Publish release on merge
+        if: github.event.pull_request.merged == true
+        uses: softprops/action-gh-release@v2
+        with:
+          draft: false
+          tag_name: v${{steps.version.outputs.version}}
+          files: |
+            microcom-*.tar.gz
+            microcom-*.tar.xz
+
+      - run: gh pr edit "$NUMBER" --add-label "$LABELS"
+        if: github.event.pull_request.merged == false
+        env:
+          GH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+          GH_REPO: ${{github.repository}}
+          NUMBER: ${{github.event.pull_request.number}}
+          LABELS: release
+
+      - run: gh pr comment "$NUMBER" --body "Release published!"
+        if: github.event.pull_request.merged == true
+        env:
+          GH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+          GH_REPO: ${{github.repository}}
+          NUMBER: ${{github.event.pull_request.number}}
+          LABELS: release

VERSION

@@ -0,0 +1 @@
+2023.09.0

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT([microcom], [2023.09.0], [[email protected]])
+AC_INIT([microcom], [m4_esyscmd_s(cat VERSION)], [[email protected]])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([dist-xz])