release-git: add MSYS2 mingw-w64-git package sync

As part of the release process, we now synchronize the mingw-w64-git
package to the MSYS2 upstream fork, enabling MSYS2 users to get Git
for Windows via their regular package manager.

This builds on the work from msys2/MINGW-packages#26470
which initially integrated the package definition into MSYS2.

Since the GitForWindowsHelper GitHub App has no access to
msys2/MINGW-packages, we:

1. Create an msys2-sync-<version> branch in git-artifacts.yml based on
   msys2/master with our mingw-w64-git/ content (commit message links
   to the git-artifacts workflow run for traceability)
2. Include this branch in the MINGW-packages.bundle
3. Push both main and the sync branch in repository-updates
4. Add a PR link to the release comment (separate paragraph asking the
   human driver to wait for repository-updates to finish first; the PR
   description links to the release workflow run)

The PR link pre-populates the title and description, so the human
driver just needs to click and submit.

This is skipped for RC releases, matching the behavior of other
repository updates.

Assisted-by: Claude Opus 4.6
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.github/workflows/git-artifacts.yml

@@ -317,7 +317,24 @@ jobs:
           if test -z "$EXISTING_GIT_TAG"
           then
             git commit -s -m "mingw-w64-git: new version ($version)" PKGBUILD &&
-            git bundle create "$b"/MINGW-packages.bundle origin/main..main
+
+            # Create MSYS2 sync branch: based on msys2/master with our mingw-w64-git/ content
+            # See https://github.com/msys2/MINGW-packages/pull/26470
+            msys2_sync_branch="msys2-sync-$version" &&
+            git fetch --depth 1 https://github.com/msys2/MINGW-packages master &&
+            git worktree add -b "$msys2_sync_branch" --no-checkout msys2-sync FETCH_HEAD &&
+            git -C msys2-sync sparse-checkout set mingw-w64-git &&
+            git -C msys2-sync checkout main -- mingw-w64-git &&
+            git -C msys2-sync commit -m "mingw-w64-git: upgrade to Git for Windows $version
+
+This commit was created by:
+$GITHUB_SERVER_URL/$GITHUB_REPOSITORY/actions/runs/$GITHUB_RUN_ID
+
+See https://github.com/git-for-windows/git/releases/tag/$version for details." &&
+            echo "::notice::Created MSYS2 sync branch $msys2_sync_branch at $(git -C msys2-sync rev-parse HEAD)" &&
+            git worktree remove msys2-sync &&
+
+            git bundle create "$b"/MINGW-packages.bundle origin/main..main FETCH_HEAD.."$msys2_sync_branch"
           elif ! git update-index --ignore-submodules --refresh ||
             ! git diff-files --ignore-submodules ||
             ! git diff-index --cached --ignore-submodules HEAD

.github/workflows/release-git.yml

@@ -140,7 +140,22 @@ jobs:
               : `Git for Windows ${baseVersion} is available! ${releaseURL}`
             const blueskyLink = `https://bsky.app/intent/compose?text=${encodeURIComponent(skeet)}`
 
-            const body = `please [Share on Bluesky](${blueskyLink}) and send [the announcement email](${announcementURL}).`
+            let body = `please [Share on Bluesky](${blueskyLink}) and send [the announcement email](${announcementURL}).`
+
+            // Add MSYS2 PR link for non-RC releases
+            // See https://github.com/msys2/MINGW-packages/pull/26470
+            if (!rc) {
+              const msys2SyncBranch = `msys2-sync-${tagName}`
+              const releaseWorkflowRunURL = `https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}`
+              const prTitle = encodeURIComponent(`mingw-w64-git: upgrade to Git for Windows ${ver}`)
+              const prBody = encodeURIComponent(`This PR synchronizes the \`mingw-w64-git\` package definition from [Git for Windows](https://github.com/git-for-windows/MINGW-packages/tree/main/mingw-w64-git).
+
+See ${releaseURL} for the release notes.
+
+This branch was pushed by ${releaseWorkflowRunURL}`)
+              const msys2PrLink = `https://github.com/msys2/MINGW-packages/compare/master...git-for-windows:MINGW-packages:${msys2SyncBranch}?expand=1&title=${prTitle}&body=${prBody}`
+              body += `\n\nPlease wait for the [repository-updates job](${releaseWorkflowRunURL}) to finish, then [open the MSYS2 sync PR](${msys2PrLink}).`
+            }
 
             const q = `repo:${process.env.OWNER}/${process.env.REPO}+is:pr+is:open+${gitSHA}`
             const { data } = await github.rest.search.issuesAndPullRequests({ q })

repository-updates.js

@@ -138,6 +138,51 @@ const pushRepositoryUpdate = async (context, setSecret, appId, privateKey, owner
     'push', `https://github.com/${owner}/${repo}`, refName
   ])
   context.log(`Done pushing ref ${refName} to ${owner}/${repo}`)
+
+  // For MINGW-packages, also push the MSYS2 sync branch from the bundle
+  // See https://github.com/msys2/MINGW-packages/pull/26470
+  // Note: This code only runs for non-RC releases (guarded by the action's `if` condition)
+  if (repo === 'MINGW-packages' && bundlePath) {
+    const fs = require('fs')
+    const version = fs.readFileSync('bundle-artifacts/next_version').toString().trim()
+    const msys2SyncBranch = `msys2-sync-${version}`
+
+    // The bundle contains a commit based on msys2/master, so we need to fetch
+    // the prerequisite commits first. Parse the bundle header to find them
+    // (lines starting with `-` before the first blank line).
+    const bundleHeader = fs.readFileSync(bundlePath, 'utf-8').split('\n\n')[0]
+    const prerequisites = bundleHeader
+      .split('\n')
+      .filter(line => line.startsWith('-'))
+      .map(line => line.slice(1).split(' ')[0])
+
+    if (prerequisites.length > 0) {
+      // Check which prerequisites are missing locally using cat-file --batch-check
+      const { spawnSync } = require('child_process')
+      const catFile = spawnSync('git', ['--git-dir', gitDir, 'cat-file', '--batch-check'], {
+        input: prerequisites.join('\n'),
+        encoding: 'utf-8'
+      })
+      const missing = catFile.stdout
+        .split('\n')
+        .filter(line => line.endsWith(' missing'))
+        .map(line => line.split(' ')[0])
+
+      if (missing.length > 0) {
+        context.log(`Fetching ${missing.length} prerequisite(s) from msys2/MINGW-packages`)
+        callGit(['--git-dir', gitDir, 'fetch', '--depth', '1',
+          'https://github.com/msys2/MINGW-packages', ...missing
+        ])
+      }
+    }
+
+    callGit(['--git-dir', gitDir, 'fetch', bundlePath, msys2SyncBranch])
+    callGit(['--git-dir', gitDir,
+      '-c', `http.extraHeader=${authorizationHeader}`,
+      'push', `https://github.com/${owner}/${repo}`, `FETCH_HEAD:refs/heads/${msys2SyncBranch}`
+    ])
+    context.log(`::notice::Pushed MSYS2 sync branch ${msys2SyncBranch} to ${owner}/${repo}`)
+  }
 }
 
 const pushGitBranch = async (context, setSecret, appId, privateKey, owner, repo, pushRefSpec) => {