screenshot_comment.yml

# Adapted from https://github.com/takahirom/roborazzi/blob/4be7f304fa23f2f00fad67ab612aec2035ac9db2/.github/workflows/CompareScreenshotComment.yml
#
# Copyright 2023 takahirom
# Copyright 2019 Square, Inc.
# Copyright The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

name: "🛠️ Screenshots: Comment"

on:
  workflow_run:
    workflows:
      - "🛠️ Screenshots: Compare"
    types:
      - completed

permissions: { }

jobs:
  Comment-CompareScreenshot:
    name: comment
    if: >
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion == 'success'

    timeout-minutes: 2

    permissions:
      actions: read # for downloading artifacts and reading the run id
      pull-requests: write # for creating a comment on pull requests

    runs-on: ubuntu-latest

    steps:
      - name: Download PR number artifact
        uses: dawidd6/action-download-artifact@09f2f74827fd3a8607589e5ad7f9398816f540fe # v3.1.4
        with:
          name: pr
          run_id: ${{ github.event.workflow_run.id }}
      - id: get-pull-request-number
        name: Get pull request number
        shell: bash
        run: |
          echo "pull_request_number=$(cat NR)" >> "$GITHUB_OUTPUT"
      - name: Download screenshot diff artifact
        uses: dawidd6/action-download-artifact@09f2f74827fd3a8607589e5ad7f9398816f540fe # v3.1.4
        with:
          run_id: ${{ github.event.workflow_run.id }}
          name: screenshot-diff
          path: screenshot-diff
      - id: check-if-there-are-valid-files
        name: Check if there are valid files
        shell: bash
        run: |
          # Find Roborazzi diff PNGs in the downloaded artifact (in <TestClass>/).
          mapfile -t files_to_add < <(find . -name "*_compare.png" -type f)
          if [ ${#files_to_add[@]} -gt 0 ]; then
            exist_valid_files="true"
          else
            exist_valid_files="false"
          fi
          echo "exist_valid_files=$exist_valid_files" >> "$GITHUB_OUTPUT"
      - id: generate-diff-reports
        name: Generate diff reports
        if: steps.check-if-there-are-valid-files.outputs.exist_valid_files == 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          REPO: ${{ github.repository }}
          RUN_ID: ${{ github.event.workflow_run.id }}
          BASE_REF: ${{ github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.pull_requests[0].base.ref || github.event.repository.default_branch }}
        shell: bash
        run: |
          # Find Roborazzi diff PNGs to mention in the comment (in <TestClass>/).
          mapfile -t files < <(find . -name "*_compare.png" -type f | sort)
          total=${#files[@]}
          # Cap the full list so we remain within GitHub's comment limit
          max_details=100

          # Group by test class - the file's immediate parent directory.
          declare -A class_counts class_files
          for file in "${files[@]}"; do
            class_dir="${file%/*}"
            class="${class_dir##*/}"
            class_counts[$class]=$(( ${class_counts[$class]:-0} + 1 ))
            class_files[$class]+="$(basename "$file")"$'\n'
          done
          mapfile -t classes < <(printf '%s\n' "${!class_counts[@]}" | sort)

          # Resolve the artifact ID so we can deep-link to its download page.
          artifact_id=$(gh api "repos/$REPO/actions/runs/$RUN_ID/artifacts" \
            --jq '.artifacts[] | select(.name=="screenshot-diff") | .id')
          artifact_url="${{ github.server_url }}/$REPO/actions/runs/$RUN_ID/artifacts/$artifact_id"

          # delimiter for multi-line output to GITHUB_OUTPUT
          delimiter="$(openssl rand -hex 8)"
          {
            echo "reports<<${delimiter}"
            echo "Snapshot diff report vs \`$BASE_REF\`. Open [\`screenshot-diff\`]($artifact_url) for diffs."
            echo ""
            for class in "${classes[@]}"; do
              count=${class_counts[$class]}
              noun=$([ "$count" -eq 1 ] && echo change || echo changes)
              echo "- **$class**: $count $noun"
            done
            echo ""
            echo "<details><summary>All $total changed screenshots</summary>"
            echo ""
            remaining=$max_details
            for class in "${classes[@]}"; do
              (( remaining > 0 )) || break
              echo "**$class**"
              while IFS= read -r name; do
                [ -z "$name" ] && continue
                (( remaining > 0 )) || break
                echo "- \`$name\`"
                remaining=$(( remaining - 1 ))
              done <<< "${class_files[$class]}"
              echo ""
            done
            if (( total > max_details )); then
              echo "_…and $((total - max_details)) more not shown._"
            fi
            echo "</details>"
            echo "${delimiter}"
          } >> "$GITHUB_OUTPUT"
      # Run unconditionally so we can clear a stale comment when regressions are fixed.
      - name: Find Comment
        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
        id: fc
        with:
          issue-number: ${{ steps.get-pull-request-number.outputs.pull_request_number }}
          comment-author: 'github-actions[bot]'
          body-includes: Snapshot diff report

      - name: Add or update comment on PR
        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4.0.0
        if: steps.generate-diff-reports.outputs.reports != ''
        with:
          comment-id: ${{ steps.fc.outputs.comment-id }}
          issue-number: ${{ steps.get-pull-request-number.outputs.pull_request_number }}
          body: ${{ steps.generate-diff-reports.outputs.reports }}
          edit-mode: replace

      # If a previous run posted a diff comment but this run has none, the regressions are fixed.
      - name: Mark previous regressions as resolved
        if: >
          steps.check-if-there-are-valid-files.outputs.exist_valid_files == 'false' &&
          steps.fc.outputs.comment-id != ''
        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4.0.0
        with:
          comment-id: ${{ steps.fc.outputs.comment-id }}
          body: |
            Snapshot diff report: Previous regressions were resolved by the latest commit.
          edit-mode: replace