GitHub action to append or replace text in a pull request description.

This action supports pull_request and push events (where the push event ocurred on a branch with an open pull request).

• content: The content to append or replace in the PR body. Can be raw text or a file path. If a file path is provided, contentIsFilePath must be set to "true".
• contentIsFilePath: Whether the content input is a file path. Defaults to "false".
• contentRegex: The regex to match against the content. Used to select a specific part of the content to use. Defaults to "" (everything).
• contentRegexFlags: The content matchregex flags to use. Defaults to "".
• regex: The regex to match against the PR body and replace with content. Defaults to "---.*".
• regexFlags: The regex flags to use. Defaults to "".
• appendContentOnMatchOnly: Whether to skip appending the content to the PR body if no regex matches are found. Defaults to "false".
• token: The GitHub token to use.

Note: append mode is the default behavior when no regex match is found for backwards compatibility with existing action users. This may change in future minor/major versions and will be noted in the changelog.

• Simple replace all text in the PR description with Hello there!:

  on:
      pull_request:
  
  jobs:
      update-pr-description:
          runs-on: ubuntu-latest
          steps:
              - name: Checkout
                uses: actions/checkout@v4
              - name: Update PR Description
                uses: nefrob/pr-description@v1.2.0
                with:
                    content: "Hello there!"
                    regex: ".*"
                    regexFlags: s
                    token: ${{ secrets.GITHUB_TOKEN }}

  Body before:

  Existing
  Body

  Body after:

  Hello there!

• Reading from a file:

  on:
      pull_request:
  
  jobs:
      update-pr-description:
          runs-on: ubuntu-latest
          steps:
              - name: Checkout
                uses: actions/checkout@v4
              - name: Update PR Description
                uses: nefrob/pr-description@v1.2.0
                with:
                    content: path/to/file.txt
                    contentIsFilePath: true
                    regex: ".*"
                    token: ${{ secrets.GITHUB_TOKEN }}

  File content:

  Hello there!
  

  Body before:

  Existing body

  Body after:

  Hello there!

• Replace text in between comments:

  on:
      pull_request:
  
  jobs:
      update-pr-description:
          runs-on: ubuntu-latest
          steps:
              - name: Checkout
                uses: actions/checkout@v4
              - name: Update PR Description
                uses: nefrob/pr-description@v1.2.0
                with:
                    content: "<!-- start match -->\nHello there!\n<!-- end match -->"
                    regex: "<!-- start match -->.*?<!-- end match -->"
                    regexFlags: ims
                    token: ${{ secrets.GITHUB_TOKEN }}

  Body before:

  <!-- start match -->
  Anything in between these comments will be replaced by a push to the PR.
  <!-- end match -->
  

  Body after:

  <!-- start match -->
  Hello there!
  <!-- end match -->
  

  This is particularly useful when paired with a pull_request_template.md that includes comments like these for automatic updates on every PR.

• Match a specific part of the content:

  on:
      pull_request:
  
  jobs:
      update-pr-description:
          runs-on: ubuntu-latest
          steps:
              - name: Checkout
                uses: actions/checkout@v4
              - name: Update PR Description
                uses: nefrob/pr-description@v1.2.0
                with:
                    content: path/to/CHANGELOG.md
                    contentIsFilePath: true
                    contentRegex: "^##([\\s\\S]*?)(?=\\n##|$)"
                    contentRegexFlags: g
                    regex: ".*"
                    token: ${{ secrets.GITHUB_TOKEN }}

  File content:

  ## 1.0.2 Bug fixes
  - Fixed bug #4
  - Fixed bug #3
  
  ## 1.0.1 Bug fixes
  - Fixed bug #2
  - Fixed bug #1
  

  Body before:

  Existing body
  

  Body after:

  ## 1.0.2 Bug fixes
  - Fixed bug #4
  - Fixed bug #3
  

  This could be used to extract the latest changes from a changelog.md or similar.