Try new strategy for auto updates (#664)

I previously added a CI that the documentation was not dirty. This turns out to be too strict: it's onerous to have contributors install the exactly-matching `nroff` setup required to sync the documentation.

Instead, the CI check now commits and pushes the change to the PR (if it's a same-fork PR), and ignores the changes if it's a PR from another fork.

The CI will push the PrepareRelease changes on master, if needed.

Fixes #653

.github/workflows/build.yml

@@ -291,6 +291,7 @@ jobs:
 
           # Workaround for incorrect filesystem permissions on /usr/share/aclocal, which
           # causes the m4 macros to be copied with incorrect permissions.
+          # https://github.com/actions/runner-images/issues/11212
           chmod u=rw,go=r m4/*.m4
 
       - name: Configure
@@ -303,7 +304,7 @@ jobs:
         run: |
           mkdir tarball-dir
           tar -C tarball-dir -xzf pcre2-*.tar.gz
-          # Budge the directory, so we don't back the version number into the
+          # Budge the directory, so we don't bake the version number into the
           # `manifest-tarball` file:
           mv tarball-dir/pcre2-* tarball-dir/pcre2-SNAPSHOT
           maint/RunManifestTest tarball-dir maint/manifest-tarball

.github/workflows/clang-analyzer.yml

@@ -23,6 +23,7 @@ jobs:
       # turn aborts when it finds that GitHub's CI machine doesn't have ICU.
       # Just turn off localisation. A future version of the ubuntu-24.04 or
       # ubuntu-latest runners might not need this workaround.
+      # https://github.com/actions/runner-images/issues/10989
       DOTNET_SYSTEM_GLOBALIZATION_INVARIANT: 1
 
     steps:

.github/workflows/dev.yml

@@ -448,13 +448,18 @@ jobs:
     # making a PR, so that everything is kept in-sync.
     name: Check autogenerated file freshness
     runs-on: ubuntu-24.04 # TODO: Update to ubuntu-latest when that switches to 24.04
+    permissions:
+      contents: write
     steps:
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           submodules: false
-          fetch-depth: 0
+          fetch-depth: 0 # Necessary for maint/PrepareRelease
           fetch-tags: false
+          # Check out the unmerged source branch for `pull_request`-triggered runs;
+          # otherwise use the tip of the branch for `workflow_dispatch` and `pull` triggers.
+          ref: ${{ github.head_ref || github.ref }}
 
       - name: PrepareRelease
         run: maint/PrepareRelease
@@ -465,15 +470,21 @@ jobs:
           rm -f src/*.generic
           make src/config.h.generic src/pcre2.h.generic
 
-      - name: Working directory clean
-        run:  |
+      # If we're in a forked repo, it's too onerous to expect contributors to run the
+      # checks locally to keep these files up to date (since the tool versions are very
+      # fussy and brittle).
+      #
+      # However, we still want to run the steps above, to check that the PrepareRelease
+      # process is able to run to completion, since it can pick up errors in the man pages.
+
+      - name: Commit and push, if not in a forked repo
+        if: github.event_name != 'pull_request' || ( ! github.event.pull_request.head.repo.fork && github.actor != 'dependabot[bot]' )
+        run: |
           if [ -n "`git status --porcelain`" ] ; then
-            (
-              echo "Dirty working tree! Affected files:"
-              git status --porcelain || true
-              echo ""
-              echo "Diff:"
-              git diff || true
-            ) >&2
-            exit 1
+            # Dirty working tree: push it
+            git config user.name "github-actions[bot]"
+            git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+            git add -u
+            git commit -m "Sync autogenerated files"
+            git push
           fi