action.yml

name: "Profile diff"
description: "Profile a pytest suite, script, or callable on base and head, then comment a CPU/memory performance diff on the PR."
branding:
  icon: "activity"
  color: "purple"

inputs:
  target:
    description: >
      profile_diff run target selector, passed through verbatim. Examples:
      '--pytest tests/', '--script path/to/script.py', or
      '--callable pkg.mod:func'.
    required: true
  python-version:
    description: "Python version for actions/setup-python."
    required: false
    default: "3.x"
  base-ref:
    description: "Git ref or SHA to profile as the base."
    required: false
    default: ${{ github.event.pull_request.base.sha }}
  top:
    description: "Keep the top N functions by cumtime."
    required: false
    default: "30"
  threshold-pct:
    description: "Ignore cumtime movements below this percentage."
    required: false
    default: "5"
  min-abs-ms:
    description: "Ignore cumtime movements below this many milliseconds."
    required: false
    default: "0"
  fail-on-regression:
    description: "If 'true', fail the job when any hotspot regresses beyond the threshold."
    required: false
    default: "false"
  github-token:
    description: "Token with 'pull-requests: write' used to post the comment."
    required: false
    default: ${{ github.token }}
  pr-number:
    description: "PR number to comment on."
    required: false
    default: ${{ github.event.pull_request.number }}

runs:
  using: "composite"
  steps:
    - name: Set up Python
      uses: actions/setup-python@v5
      with:
        python-version: ${{ inputs.python-version }}

    - name: Profile head (current checkout)
      shell: bash
      run: |
        set -euo pipefail
        export PYTHONPATH="${{ github.action_path }}:${PYTHONPATH:-}"
        # The target selector goes LAST so a '--pytest ...' target can forward
        # its own flags without colliding with profile_diff's options.
        python -m profile_diff run \
          --label head --top "${{ inputs.top }}" \
          --out "${RUNNER_TEMP}/pd-head.json" \
          ${{ inputs.target }}

    - name: Profile base (${{ inputs.base-ref }})
      shell: bash
      run: |
        set -euo pipefail
        export PYTHONPATH="${{ github.action_path }}:${PYTHONPATH:-}"
        git fetch --no-tags --depth=1 origin "${{ inputs.base-ref }}" || true
        git worktree add --detach "${RUNNER_TEMP}/pd-base" "${{ inputs.base-ref }}"
        ( cd "${RUNNER_TEMP}/pd-base" && \
          python -m profile_diff run \
            --label base --top "${{ inputs.top }}" \
            --out "${RUNNER_TEMP}/pd-base.json" \
            ${{ inputs.target }} )
        git worktree remove --force "${RUNNER_TEMP}/pd-base"

    - name: Compare and render Markdown
      shell: bash
      run: |
        set -euo pipefail
        export PYTHONPATH="${{ github.action_path }}:${PYTHONPATH:-}"
        python -m profile_diff compare \
          "${RUNNER_TEMP}/pd-base.json" "${RUNNER_TEMP}/pd-head.json" \
          --threshold-pct "${{ inputs.threshold-pct }}" \
          --min-abs-ms "${{ inputs.min-abs-ms }}" \
          --top "${{ inputs.top }}" \
          --format markdown --out "${RUNNER_TEMP}/pd-diff.md"
        echo "----- profile-diff report -----"
        cat "${RUNNER_TEMP}/pd-diff.md"

    - name: Comment on PR
      if: ${{ inputs.github-token != '' && inputs.pr-number != '' }}
      shell: bash
      env:
        GITHUB_TOKEN: ${{ inputs.github-token }}
        GITHUB_REPOSITORY: ${{ github.repository }}
        PR_NUMBER: ${{ inputs.pr-number }}
      run: |
        set -euo pipefail
        export PYTHONPATH="${{ github.action_path }}:${PYTHONPATH:-}"
        python -m profile_diff comment "${RUNNER_TEMP}/pd-diff.md"

    - name: Enforce regression gate
      if: ${{ inputs.fail-on-regression == 'true' }}
      shell: bash
      run: |
        set -euo pipefail
        export PYTHONPATH="${{ github.action_path }}:${PYTHONPATH:-}"
        # Re-run compare purely for its exit code so the comment is posted first.
        python -m profile_diff compare \
          "${RUNNER_TEMP}/pd-base.json" "${RUNNER_TEMP}/pd-head.json" \
          --threshold-pct "${{ inputs.threshold-pct }}" \
          --min-abs-ms "${{ inputs.min-abs-ms }}" \
          --top "${{ inputs.top }}" \
          --format text --fail-on-regression >/dev/null