zed/.github/workflows/pr-size-label.yml

# PR Size Check — Label & Comment
#
# Triggered by workflow_run after pr-size-check.yml completes.
# Downloads the size result artifact and applies labels + comments.
#
# This runs on the base repo with full GITHUB_TOKEN write access,
# so it works for both same-repo and fork PRs.
#
# Security note: The artifact is treated as untrusted data — only
# structured JSON fields (PR number, size label, color, boolean) are
# read. No artifact content is executed or interpolated into shell.

name: PR Size Label

on:
  workflow_run:
    workflows: ["PR Size Check"]
    types: [completed]

jobs:
  apply-labels:
    if: >
      github.repository_owner == 'zed-industries' &&
      github.event.workflow_run.conclusion == 'success'
    permissions:
      contents: read
      pull-requests: write
      issues: write
    runs-on: ubuntu-latest
    timeout-minutes: 5
    steps:
      - name: Download size result artifact
        id: download
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
        with:
          script: |
            const fs = require('fs');
            const path = require('path');

            const allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: context.payload.workflow_run.id,
            });

            const match = allArtifacts.data.artifacts.find(a => a.name === 'pr-size-result');
            if (!match) {
              console.log('No pr-size-result artifact found, skipping');
              core.setOutput('found', 'false');
              return;
            }

            const download = await github.rest.actions.downloadArtifact({
              owner: context.repo.owner,
              repo: context.repo.repo,
              artifact_id: match.id,
              archive_format: 'zip',
            });

            const temp = path.join(process.env.RUNNER_TEMP, 'pr-size');
            fs.mkdirSync(temp, { recursive: true });
            fs.writeFileSync(path.join(temp, 'result.zip'), Buffer.from(download.data));
            core.setOutput('found', 'true');

      - name: Unzip artifact
        if: steps.download.outputs.found == 'true'
        env:
          ARTIFACT_DIR: ${{ runner.temp }}/pr-size
        run: unzip "$ARTIFACT_DIR/result.zip" -d "$ARTIFACT_DIR"

      - name: Apply labels and comment
        if: steps.download.outputs.found == 'true'
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
        with:
          script: |
            const fs = require('fs');
            const path = require('path');

            const temp = path.join(process.env.RUNNER_TEMP, 'pr-size');
            const resultPath = path.join(temp, 'result.json');
            if (!fs.existsSync(resultPath)) {
              console.log('No result.json found, skipping');
              return;
            }

            const result = JSON.parse(fs.readFileSync(resultPath, 'utf8'));

            // Validate artifact data (treat as untrusted)
            const prNumber = Number(result.pr_number);
            const totalChanges = Number(result.total_changes);
            const sizeLabel = String(result.size_label);
            const labelColor = String(result.label_color);
            const hasReviewGuidance = Boolean(result.has_review_guidance);

            if (!prNumber || !sizeLabel.startsWith('Size ')) {
              core.setFailed(`Invalid artifact data: pr=${prNumber}, label=${sizeLabel}`);
              return;
            }

            console.log(`PR #${prNumber}: ${totalChanges} LOC, ${sizeLabel}`);

            // --- Size label (idempotent) ---
            const existingLabels = (await github.rest.issues.listLabelsOnIssue({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            })).data.map(l => l.name);

            const existingSizeLabels = existingLabels.filter(l => l.startsWith('Size '));
            const alreadyCorrect = existingSizeLabels.length === 1 && existingSizeLabels[0] === sizeLabel;

            if (!alreadyCorrect) {
              for (const label of existingSizeLabels) {
                await github.rest.issues.removeLabel({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: prNumber,
                  name: label,
                });
              }

              try {
                await github.rest.issues.createLabel({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  name: sizeLabel,
                  color: labelColor,
                });
              } catch (e) {
                if (e.status !== 422) throw e;
              }

              await github.rest.issues.addLabels({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                labels: [sizeLabel],
              });
            }

            // --- Large PR handling (400+ LOC) ---
            if (totalChanges >= 400) {
              if (!existingLabels.includes('large-pr')) {
                try {
                  await github.rest.issues.createLabel({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    name: 'large-pr',
                    color: 'e99695',
                  });
                } catch (e) {
                  if (e.status !== 422) throw e;
                }

                await github.rest.issues.addLabels({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: prNumber,
                  labels: ['large-pr'],
                });
              }

              // Comment once with guidance
              const MARKER = '<!-- pr-size-check -->';
              const { data: comments } = await github.rest.issues.listComments({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
              });

              const alreadyCommented = comments.some(c => c.body.includes(MARKER));
              if (!alreadyCommented) {
                let body = `${MARKER}\n`;
                body += `### :straight_ruler: PR Size: **${totalChanges} lines changed** (${sizeLabel})\n\n`;
                body += `Please note: this PR exceeds the 400 LOC soft limit.\n`;
                body += `- Consider **splitting** into separate PRs if the changes are separable\n`;
                body += `- Ensure the PR description includes a **guided tour** in the "How to Review" section so reviewers know where to start\n`;

                if (hasReviewGuidance) {
                  body += `\n:white_check_mark: "How to Review" section appears to include guidance — thank you!\n`;
                }

                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: prNumber,
                  body: body,
                });
              }
            }

            console.log(`PR #${prNumber}: labeled ${sizeLabel}, done`);
defaults:
  run:
    shell: bash -euxo pipefail {0}