CI: add distribution version consistency checks

This should make sure that we do not forget to update the DISTRO_VERSION
and DISTRO_CODENAME when a new tag is created or a new yocto version branch
is started.

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>

.github/workflows/distribution-version.py

@@ -0,0 +1,89 @@
+import os
+import re
+
+import bb.tinfoil
+import git
+
+# TODO: add minor version numbers once we have them
+RE_VERSION_TAG = "v(?P<year>[0-9][0-9])\.(?P<month>[0-9][0-9])"
+RE_VERSION_BB = "(?P<year>[0-9][0-9])\.(?P<month>[0-9][0-9])(?P<dev>$|\+dev)"
+
+
+def bb_variables(names):
+    ret = dict()
+
+    with bb.tinfoil.Tinfoil(tracking=True, setup_logging=True) as tinfoil:
+        tinfoil.prepare(quiet=2, config_only=True)
+        d = tinfoil.config_data
+
+        for name in names:
+            ret[name] = d.getVar(name)
+
+    return ret
+
+
+def git_prev_tag():
+    repo = git.Repo()
+
+    current_commit_is_tagged = True
+
+    for commit in repo.iter_commits():
+        for tag in repo.tags:
+            if tag.commit == commit:
+                return (tag, current_commit_is_tagged)
+
+        current_commit_is_tagged = False
+
+
+def check_version(distro_version):
+    prev_tag, commit_is_tagged = git_prev_tag()
+
+    print(f"Checking tag {prev_tag.name} against version {distro_version}")
+
+    version_tag = re.fullmatch(RE_VERSION_TAG, prev_tag.name)
+    version_tag_numeric = int(version_tag["year"]) * 100 + int(version_tag["month"])
+
+    version_bb = re.fullmatch(RE_VERSION_BB, distro_version)
+    version_bb_numeric = int(version_bb["year"]) * 100 + int(version_bb["month"])
+
+    if commit_is_tagged:
+        # The version in a tagged commit must match the version in the tag's name.
+        assert version_bb["dev"] == ""
+        assert version_tag_numeric == version_bb_numeric
+
+    elif version_bb["dev"] == "":
+        # Release candidates already have the next release version set,
+        # but there must not be a tag with the same or a newer version number
+        # in the current commits history.
+        assert version_bb_numeric > version_tag_numeric
+
+    else:
+        # Non release candidate versions should have the previous tagged
+        # version number plus the +dev suffix set.
+        assert version_bb_numeric == version_tag_numeric
+
+
+def check_codename(codename):
+    base_ref = os.environ.get("GITHUB_BASE_REF")
+    ref = os.environ.get("GITHUB_REF")
+
+    if base_ref is not None:
+        print(f"Checking codename {codename} against pull request into {base_ref}")
+        assert codename == f"tacos-{base_ref}"
+    elif ref is not None:
+        print(f"Checking codename {codename} against branch {ref}")
+        assert codename == f"tacos-{ref}"
+    else:
+        print("Running outside of GitHub CI. Skipping codename check")
+        return
+
+
+def main():
+    variables = bb_variables(("DISTRO_VERSION", "DISTRO_CODENAME"))
+
+    check_version(variables["DISTRO_VERSION"])
+    check_codename(variables["DISTRO_CODENAME"])
+
+
+if __name__ == "__main__":
+    main()

.github/workflows/distribution-version.yaml

@@ -0,0 +1,23 @@
+name: distribution version
+
+on:
+  push:
+  pull_request:
+jobs:
+  check:
+    name: version consistency
+    runs-on: ubuntu-latest
+    if: github.repository == 'linux-automation/meta-lxatac'
+    steps:
+      - name: Install required packages
+        run: |
+          sudo apt-get install diffstat chrpath python3-git
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          submodules: recursive
+      - name: Check version number and codename
+        run: |
+          source oe-init-build-env && cd -
+          python3 .github/workflows/distribution-version.py