workflows: Add a test to ensure that the LLVM version is correct

[tstellar]

Summary

This should prevent mistakes like Issue#55137.

[thieta]

I think this is fine. But I wonder if we should split out the version into a separate file that can be easier to parse and so we don't have to edit the version in several different places. In my last job we usually had a single VERSION file in the root that we read from CMake and all other places that needed the current version.

[mgorny]

Could you also include checking llvm/utils/lit/lit/__init__.py while at it?

[tstellar]

In D124539#3479378, @thieta wrote:

I think this is fine. But I wonder if we should split out the version into a separate file that can be easier to parse and so we don't have to edit the version in several different places. In my last job we usually had a single VERSION file in the root that we read from CMake and all other places that needed the current version.

I think we could put it in the cmake/ directory.

[tstellar]

This was committed to the release/14.x branch: 2e7e14177186dc417a49dbf88493dabde0572e22

.github/workflows/version-check.py

+#!/usr/bin/python3
+
+from git import Repo
+import re
+import sys
+
+version = sys.argv[1]
+
+repo = Repo()
+
+tag = repo.git.describe(tags = True, abbrev=0)
+m = re.match('llvmorg-([0-9]+)\.([0-9]+)\.([0-9]+)', tag)
+if not m:
+    print("error: Tag is not valid: ", tag)
+    sys.exit(1)
+
+expected_major = m.group(1)
+expected_minor = m.group(2)
+expected_patch = int(m.group(3)) + 1
+expected_version = f"{expected_major}.{expected_minor}.{expected_patch}"
+
+m = re.match("[0-9]+\.[0-9]+\.[0-9]+", version)
+if not m:
+    print("error: Version is not valid: ", version)
+    sys.exit(1)
+
+if version != expected_version:
+    print("error: Expected version", expected_version, "but found version", version)
+    sys.exit(1)
+
+print("Versions match:", version, expected_version)
+sys.exit(0)

.github/workflows/version-check.yml

+name: LLVM Project Version Check
+
+on:
+  push:
+    branches:
+      - 'release/**'
+    pull_request:
+
+
+jobs:
+  version_check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Fetch LLVM sources
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: Install dependencies
+        run: |
+          pip install -r ./llvm/utils/git/requirements.txt
+
+      - name: Version Check
+        run: |
+          version=`grep -o 'LLVM_VERSION_\(MAJOR\|MINOR\|PATCH\) [0-9]\+' llvm/CMakeLists.txt  | cut -d ' ' -f 2 | tr "\n" "." | sed 's/.$//g'`
+          .github/workflows/version-check.py $version