[PATCH v2 1/1] ci: new github-action for git-l10n code review

[Jiang Xin <worldhello.net@gmail.com>]

From: Jiang Xin <zhiyou.jx@alibaba-inc.com>

Git l10n uses github pull request for code review. A helper program
"git-po-helper" can be used to check typos in ".po" files, validate
syntax, and check commit message. It would be convenient to integrate
this helper program to CI and add comments in pull request.

The new github-action workflow is added in ".github/workflows/l10n.yml",
which is disabled by default. To turn it on for the git-l10n related
repositories, such as "git-l10n/git-po", we can add a new branch named
"ci-config" and create a simple shell script at "ci/config/allow-l10n"
in this branch.

The new l10n workflow listens to two types of github events: "push" and
"pull_request_target". The "pull_request_target" event is just like the
"pull_request" event, but provides write permission to create comments
for pull request.

For a "push" event, it will scan commits one by one. If a commit does
not look like a l10n commit (no file in "po/" has been changed), it
will immediately fail without checking for further commits. While for a
"pull_request_target" event, all new introduced commits will be scanned.

"git-po-helper" will generate two kinds of suggestions, errors and
warnings. A l10n contributor should try to fix all the errors, and
should pay attention to the warnings. All the errors and warnings will
be reported in the last step of the l10n workflow with two message
groups. For a "pull_request_target" event, will create additional
comments in the pull request to report the result.

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
---
 .github/workflows/l10n.yml | 156 +++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 .github/workflows/l10n.yml

diff --git a/.github/workflows/l10n.yml b/.github/workflows/l10n.yml
new file mode 100644
index 0000000..bb4d8b3
--- /dev/null
+++ b/.github/workflows/l10n.yml
@@ -0,0 +1,156 @@
+name: git-l10n
+
+on: [push, pull_request_target]
+
+jobs:
+  ci-config:
+    runs-on: ubuntu-latest
+    outputs:
+      enabled: ${{ steps.check-l10n.outputs.enabled }}
+    steps:
+      - name: try to clone ci-config branch
+        run: |
+          git -c protocol.version=2 clone \
+            --no-tags \
+            --single-branch \
+            -b ci-config \
+            --depth 1 \
+            --no-checkout \
+            --filter=blob:none \
+            https://github.com/${{ github.repository }} \
+            config-repo &&
+          cd config-repo &&
+          git checkout HEAD -- ci/config || : ignore
+      - id: check-l10n
+        name: check whether CI is enabled for l10n
+        run: |
+          enabled=no
+          if test -x config-repo/ci/config/allow-l10n &&
+             config-repo/ci/config/allow-l10n '${{ github.ref }}'
+          then
+            enabled=yes
+          fi
+          echo "::set-output name=enabled::$enabled"
+
+  git-po-helper:
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: '0'
+    - name: Fetch missing commits
+      id: fetch-commits
+      run: |
+        if test "${{ github.event_name }}" = "pull_request_target"
+        then
+          base=${{ github.event.pull_request.base.sha }}
+          head=${{ github.event.pull_request.head.sha }}
+        else
+          base=${{ github.event.before }}
+          head=${{ github.event.after }}
+        fi
+        for commit in $base $head
+        do
+          if echo $commit | grep -q "^00*$"
+          then
+            continue
+          fi
+          if ! git rev-parse --verify --end-of-options "$commit^{commit}" --
+          then
+            git fetch origin $commit
+          fi
+        done
+        echo "::set-output name=base::$base"
+        echo "::set-output name=head::$head"
+
+    - uses: actions/setup-go@v2
+      with:
+        go-version: ">=1.16"
+    - name: Install git-po-helper
+      run: |
+        go install github.com/git-l10n/git-po-helper@main
+    - name: Install other dependencies
+      run: |
+        sudo apt-get update -q &&
+        sudo apt-get install -q -y gettext
+    - name: Run git-po-helper
+      id: check-commits
+      run: |
+        exit_code=0
+        git-po-helper check-commits \
+            --github-action \
+            --github-action-event "${{ github.event_name }}" -- \
+            ${{ steps.fetch-commits.outputs.base }}..${{ steps.fetch-commits.outputs.head }} \
+            >git-po-helper.out 2>&1 ||
+          exit_code=$?
+        echo "::set-output name=exit_code::$exit_code"
+        has_error_msg=
+        has_warning_msg=
+        if test $exit_code -ne 0
+        then
+          has_error_msg=yes
+          if test "${{ github.event_name }}" = "pull_request_target"
+          then
+            echo "ERROR_MSG<<EOF" >>$GITHUB_ENV
+            grep -v -e "^level=warning" -e WARNING git-po-helper.out |
+              perl -pe 's/\e\[[0-9;]*m//g' >>$GITHUB_ENV
+            echo "EOF" >>$GITHUB_ENV
+          fi
+        fi
+        if grep -q -e "^level=warning" -e WARNING git-po-helper.out
+        then
+          has_warning_msg=yes
+          if test "${{ github.event_name }}" = "pull_request_target"
+          then
+            echo "WARNING_MSG<<EOF" >>$GITHUB_ENV
+            grep -v -e "^level=error" -e ERROR git-po-helper.out |
+              perl -pe 's/\e\[[0-9;]*m//g' >>$GITHUB_ENV
+            echo "EOF" >>$GITHUB_ENV
+          fi
+        fi
+        echo "::set-output name=has_error_msg::$has_error_msg"
+        echo "::set-output name=has_warning_msg::$has_warning_msg"
+    - name: Report errors in comment for pull request
+      uses: mshick/add-pr-comment@v1
+      if: steps.check-commits.outputs.has_error_msg == 'yes' && github.event_name == 'pull_request_target'
+      continue-on-error: true
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        repo-token-user-login: 'github-actions[bot]'
+        message: |
+          Errors found by git-po-helper in workflow ${{ github.workflow }}:
+          ```
+          ${{ env.ERROR_MSG }}
+          ```
+    - name: Report warnings in comment for pull request
+      uses: mshick/add-pr-comment@v1
+      if: steps.check-commits.outputs.has_warning_msg == 'yes' && github.event_name == 'pull_request_target'
+      continue-on-error: true
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        repo-token-user-login: 'github-actions[bot]'
+        message: |
+          Warnings found by git-po-helper in workflow ${{ github.workflow }}:
+          ```
+          ${{ env.WARNING_MSG }}
+          ```
+    - name: Final report
+      run: |
+        if test "${{ steps.check-commits.outputs.has_error_msg }}" = "yes"
+        then
+          echo "::group::Errors found by git-po-helper"
+          grep -v -e "^level=warning" -e WARNING git-po-helper.out
+          echo "::endgroup::"
+        fi
+        if test "${{ steps.check-commits.outputs.has_warning_msg }}" = "yes"
+        then
+          echo "::group::Warnings found by git-po-helper"
+          grep -v -e "^level=error" -e ERROR git-po-helper.out
+          echo "::endgroup::"
+        fi
+        if test ${{ steps.check-commits.outputs.exit_code }} -ne 0
+        then
+          exit ${{ steps.check-commits.outputs.exit_code }}
+        fi
-- 
2.33.0