CI: Compute a job matrix

.ci/ci-prepare.py

@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+#
+# Compute a list of modified packages and check each package by reading PKGBUILD, what msystem architectures are
+# required for building packages.
+#
+# Outputs:
+#  jobmatrix        - A JSON encoded array of dictionaries containing: 'icon', 'msystem' and 'runner' items.
+#  modifiedPackages - A space separated list of modified package names.
+#
+from json       import dumps
+from os         import getenv
+from pathlib    import Path
+from re         import compile, MULTILINE
+from subprocess import check_output
+from textwrap   import dedent
+
+availableJobs = [
+  {"icon": "🟨", "msystem": "UCRT64",     "runner": "windows-2022"},
+  {"icon": "🟧", "msystem": "CLANG64",    "runner": "windows-2022"},
+  {"icon": "🟦", "msystem": "MINGW64",    "runner": "windows-2022"},
+  {"icon": "⬛", "msystem": "MINGW32",    "runner": "windows-2022"},
+  {"icon": "🟪", "msystem": "CLANGARM64", "runner": "windows-11-arm"}
+]
+defaultMinGWArch = {"mingw32", "mingw64", "ucrt64", "clang64"}
+
+def git_log(diff) -> list:
+  output = check_output(["git", "log", "--pretty=format:", "--name-only", diff]).decode("utf-8").strip()
+  return output.splitlines()
+
+changes =  set(Path(file) for file in git_log("upstream/master.."))
+# changes |= set(Path(file) for file in git_log("HEAD^.."))                  # Delivers same result as previous command. What's the use case?
+# changes = list(dict.fromkeys(x.split("::")[-1] for x in sorted(changes)))  # What's the use case?
+
+print(f"Modified files:")
+for change in changes:
+  print(f"  {change}")
+
+modifiedPackages = [path.parent for path in changes if path.exists() and path.name == "PKGBUILD"]
+
+print("Modified packages:")
+for packagePath in modifiedPackages:
+  print(f"  {packagePath.name}")
+
+architectures = set()
+pattern = compile(r"""^mingw_arch=\(('|")(.*?)('|")\)""", flags=MULTILINE)
+print("Inspecting PKGBUILD files for 'mingw_arch' settings ...")
+for packagePath in modifiedPackages:
+  pkgBuildPath = packagePath / "PKGBUILD"
+  print(f"  {pkgBuildPath}")
+  with pkgBuildPath.open("r", encoding="utf-8") as f:
+    content = f.read()
+
+  if (match := pattern.search(content)) is not None:
+    print(f"    {match[0]}")
+    architectures |= set(arch.replace("'", "").lower() for arch in match[2].split(" ") if arch != "")
+  else:
+    print("    'mingw_arch' not configured => using defaults")
+    architectures |= defaultMinGWArch
+
+  if len(architectures) == len(availableJobs):
+    if architectures == {job["msystem"].lower() for job in availableJobs}:
+      print("All build architectures are needed.")
+      break
+    else:
+      print("Collected an unknown architecture!")
+      print(f"::error title=Unknown Architecture::While collecting necessary architectures, an unknown architecture was discovered. {architectures}")
+      exit(1)
+
+print("Necessary build architectures:")
+for architecture in architectures:
+  print(f"  {architecture}")
+
+jobs = [job for job in availableJobs if job["msystem"].lower() in architectures]
+print("Jobs to start:")
+for job in jobs:
+  print(f"  {job["icon"]} {job["msystem"]} on {job["runner"]}")
+
+githubOutput = Path(getenv("GITHUB_OUTPUT"))
+print(f"GITHUB_OUTPUT: {githubOutput}")
+with githubOutput.open("a+", encoding="utf-8") as f:
+  f.write(dedent(f"""\
+    jobmatrix={dumps(jobs)}
+    modifiedPackages={' '.join(str(package) for package in modifiedPackages)}
+  """))
+
+if len(modifiedPackages) == 0 or len(jobs) == 0:
+  print(f"::error title=No Action Required::There have been no modifications to packages.")
+  exit(1)

.github/workflows/main.yml

@@ -9,24 +9,58 @@ on:
   pull_request:
 
 jobs:
+  prepare:
+    name: 🖥️ Compute job matrix
+    runs-on: ubuntu-24.04
+    outputs:
+      jobmatrix:        ${{ steps.compute.outputs.jobmatrix }}
+      modifiedPackages: ${{ steps.compute.outputs.modifiedPackages }}
+    steps:
+      - name: ⏬ Checkout repository
+        uses: actions/checkout@v6
+        with:
+#          path: temp
+          fetch-depth: 0
+          filter: blob:none
+          persist-credentials: false
+
+      - name: 🔝 Add upstream as a second remote
+        run: |
+          UPSTREAM=https://github.com/MSYS2/MINGW-packages
+          printf -- "Add remote 'upstream' -> ${UPSTREAM}\n"
+          git remote add upstream "${UPSTREAM}"
+          printf -- "fetch from upstream ...\n"
+          git fetch --quiet upstream
+          printf -- "Remotes:\n"
+          git remote -v
+          printf -- "Branches:\n"
+          git branch -rv
+
+      - name: 🔍 Find modified packages and used msystems
+        id: compute
+        run: .ci/ci-prepare.py
+
+# TODO: An error could be created if package files were modified, but PKGBUILD was not.
+      - name: 🪲 Debug
+        run: |
+          printf -- '${{ steps.compute.outputs.jobmatrix }}\n'
+
   build:
-    if: ${{ github.event_name != 'push' || github.ref != 'refs/heads/master'}}
+    needs:
+      - prepare
+    # Don't run: if pushed to master or if nothing was modified
+    if: ${{ ! ((github.event_name == 'push' && github.ref == 'refs/heads/master') || needs.prepare.outputs.modifiedPackages == '') }}
     strategy:
       fail-fast: false
       matrix:
-        include: [
-          { msystem: UCRT64, runner: windows-2022},
-          { msystem: CLANG64, runner: windows-2022},
-          { msystem: MINGW64, runner: windows-2022},
-          { msystem: MINGW32, runner: windows-2022},
-          { msystem: CLANGARM64, runner: windows-11-arm}
-        ]
-    name: ${{ matrix.msystem }}
+        # Matrix elements: icon, msystem, runner
+        include: ${{ fromJson(needs.prepare.outputs.jobmatrix) }}
+    name: ${{ matrix.icon }} ${{ matrix.msystem }}
     runs-on: ${{ matrix.runner }}
     steps:
       - name: Gather Facts
         id: facts
-        run : |
+        run: |
           Get-PSDrive -PSProvider FileSystem | Format-Table -AutoSize -Wrap
           Get-CIMInstance -Class Win32_Processor | Select-Object -Property Name
           Get-CIMInstance Win32_PhysicalMemory | Measure-Object -Property Capacity -Sum | Format-Table @{n="TotalPhysicalMemory";e={$_.Sum}}
@@ -91,7 +125,10 @@ jobs:
           if-no-files-found: ignore
 
   check:
-    needs: [build]
+    needs:
+      - prepare
+      - build
+    if: ${{ needs.prepare.outputs.modifiedPackages != '' }}
     runs-on: windows-2022
     steps:
       - uses: actions/checkout@v6
@@ -127,8 +164,11 @@ jobs:
           python .ci/ci-check.py "${{ runner.temp }}/artifacts"
 
   package-grokker:
+    needs:
+      - prepare
+      - build
+    if: ${{ needs.prepare.outputs.modifiedPackages != '' }}
     runs-on: ubuntu-latest
-    needs: build
     name: package-grokker-${{ matrix.msystem }}
     strategy:
       fail-fast: false