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https://github.com/redhat-plumbers-in-action/differential-shellcheck

🐚 GitHub Action for running ShellCheck differentially
https://github.com/redhat-plumbers-in-action/differential-shellcheck

bash differential-scans docker full-scans github-action linter sarif sast shell shellcheck shellcheck-action

Last synced: 7 days ago
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🐚 GitHub Action for running ShellCheck differentially

Awesome Lists containing this project

README 

        




  Differential ShellCheck

  
Differential ShellCheck



[![GitHub Marketplace][market-status]][market] [![Lint Code Base][linter-status]][linter] [![Unit Tests][test-status]][test]



![OSSF-Scorecard Score][scorecard-status] [![OpenSSF Best Practices][best-practices-status]][best-practices] [![codecov][codecov-status]][codecov]



[market]: https://github.com/marketplace/actions/differential-shellcheck

[market-status]: https://img.shields.io/badge/Marketplace-Differential%20Shellcheck-blue.svg?colorA=24292e&colorB=0366d6&style=flat&longCache=true&logo=data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA4AAAAOCAYAAAAfSC3RAAAABHNCSVQICAgIfAhkiAAAAAlwSFlzAAAM6wAADOsB5dZE0gAAABl0RVh0U29mdHdhcmUAd3d3Lmlua3NjYXBlLm9yZ5vuPBoAAAERSURBVCiRhZG/SsMxFEZPfsVJ61jbxaF0cRQRcRJ9hlYn30IHN/+9iquDCOIsblIrOjqKgy5aKoJQj4O3EEtbPwhJbr6Te28CmdSKeqzeqr0YbfVIrTBKakvtOl5dtTkK+v4HfA9PEyBFCY9AGVgCBLaBp1jPAyfAJ/AAdIEG0dNAiyP7+K1qIfMdonZic6+WJoBJvQlvuwDqcXadUuqPA1NKAlexbRTAIMvMOCjTbMwl1LtI/6KWJ5Q6rT6Ht1MA58AX8Apcqqt5r2qhrgAXQC3CZ6i1+KMd9TRu3MvA3aH/fFPnBodb6oe6HM8+lYHrGdRXW8M9bMZtPXUji69lmf5Cmamq7quNLFZXD9Rq7v0Bpc1o/tp0fisAAAAASUVORK5CYII=



[linter]: https://github.com/redhat-plumbers-in-action/differential-shellcheck/actions/workflows/linter.yml

[linter-status]: https://github.com/redhat-plumbers-in-action/differential-shellcheck/actions/workflows/linter.yml/badge.svg



[test]: https://github.com/redhat-plumbers-in-action/differential-shellcheck/actions/workflows/unit-test.yml

[test-status]: https://github.com/redhat-plumbers-in-action/differential-shellcheck/actions/workflows/unit-test.yml/badge.svg



[codecov]: https://codecov.io/gh/redhat-plumbers-in-action/differential-shellcheck

[codecov-status]: https://codecov.io/gh/redhat-plumbers-in-action/differential-shellcheck/branch/main/graph/badge.svg?token=9E9K03DRX5



[scorecard-status]: https://img.shields.io/ossf-scorecard/github.com/redhat-plumbers-in-action/differential-shellcheck?label=OSSF-Scorecard%20Score



[best-practices]: https://bestpractices.coreinfrastructure.org/projects/6540

[best-practices-status]: https://bestpractices.coreinfrastructure.org/projects/6540/badge



This repository hosts code for running Differential ShellCheck in GitHub Actions. Idea of having something like a Differential ShellCheck was first introduced in [@fedora-sysv/initscripts](https://github.com/fedora-sysv/initscripts). Initscripts needed some way to verify incoming Pull Requests without getting warnings and errors about already merged and for years working code. Therefore, Differential ShellCheck was born.



## How does it work



First Differential ShellCheck gets a list of changed shell scripts based on file extensions, shebangs and script list, if provided. Then it calls [@koalaman/shellcheck](https://github.com/koalaman/shellcheck) on those scripts where it stores ShellCheck output for later use. Then it switches from `HEAD` to provided `BASE` and runs ShellCheck on the same files as before and stores output to a separate file.



To evaluate results, Differential ShellCheck uses utilities `csdiff` and `csgrep` from [@csutils/csdiff](https://github.com/csutils/csdiff). First `csdiff` is used to get a list/number of fixed and added errors. And then `csgrep` is used to output the results in a nice colorized way to console and optionally into GitHub GUI as a security alert.



## Features



* Shell scripts auto-detection based on shebangs, ShellCheck directives, file extensions and more

  * supported shell interpreters are: `sh`, `ash`, `bash`, `dash`, `ksh` and `bats`

  * supported shebangs are: `#!/bin/`, `#!/usr/bin/`, `#!/usr/local/bin/`, `#!/bin/env␣`, `#!/usr/bin/env␣` and `#!/usr/local/bin/env␣` ; e.g. `#!/bin/env␣bash`

  * support for ShellCheck directives ; e.g. `# shellcheck shell=bash`

  * support for [`emacs` modes specifications](https://www.gnu.org/software/emacs/manual/html_node/emacs/Choosing-Modes.html) ; e.g. `# -*- sh -*-`

  * support for [`vi/vim` modeline specifications](http://vimdoc.sourceforge.net/htmldoc/options.html#modeline) ; e.g. `# vi: set filetype=sh`, `# vim: ft=sh`

* Ability to allowlist specific error codes

* Statistics about fixed and added defects and their severity

* Colored console output with emojis

* [SARIF support](https://docs.github.com/en/code-security/code-scanning/integrating-with-code-scanning/sarif-support-for-code-scanning) - warnings are visible in the `Changed files` tab of the Pull-Request and as [comment alerts on Pull-Requests](https://github.blog/changelog/2022-06-02-users-can-view-and-comment-on-code-scanning-alerts-on-the-conversation-tab-in-a-pull-request/)

* Ability to run in a verbose mode when run with [debug option](https://github.blog/changelog/2022-05-24-github-actions-re-run-jobs-with-debug-logging/)

* Results displayed as [Job Summaries](https://github.blog/2022-05-09-supercharging-github-actions-with-job-summaries/) - [example](docs/images/job-summary-light.png)

* Ability to configure Differential ShellCheck using [`.shellcheckrc`](https://github.com/koalaman/shellcheck/blob/master/shellcheck.1.md#rc-files)



## Usage



Example of running Differential ShellCheck:



```yml

name: Differential ShellCheck

on:

  push:

    branches: [ main ]

  pull_request:

    branches: [ main ]



permissions:

  contents: read



jobs:

  lint:

    runs-on: ubuntu-latest



    permissions:

      # required for all workflows

      security-events: write



      # only required for workflows in private repositories

      actions: read

      contents: read



    steps:

      - name: Repository checkout

        uses: actions/checkout@v4

        with:

          # Differential ShellCheck requires full git history

          fetch-depth: 0



      - id: ShellCheck

        name: Differential ShellCheck

        uses: redhat-plumbers-in-action/differential-shellcheck@v5

        with:

          token: ${{ secrets.GITHUB_TOKEN }}



      - if: always()

        name: Upload artifact with ShellCheck defects in SARIF format

        uses: actions/upload-artifact@v4

        with:

          name: Differential ShellCheck SARIF

          path: ${{ steps.ShellCheck.outputs.sarif }}

```



> [!IMPORTANT]

>

> _`fetch-depth: 0` is required to run `differential-shellcheck` successfully. It fetches all git history._



  Console output example

  


    Console output example

  



  Example of Job Summary

  


    

      

      Example of Job Summary

    

  



  Example of output in Changed files tab

  


    

      

      Example of output in Changed files tab

    

  



  Example of @github-code-scanning bot review comment

  


    

      

      Example of @github-code-scanning bot review comment

    

  



### Real life examples of usage



* [`rbenv/rbenv`](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/rbenv/rbenv%24+file:%5E%5C.github/workflows+redhat-plumbers-in-action/differential-shellcheck&patternType=literal) [![GitHub Repo stars](https://img.shields.io/github/stars/rbenv/rbenv?style=social)](https://github.com/rbenv/rbenv)



* [`systemd/systemd`](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/systemd/systemd%24+file:%5E%5C.github/workflows+redhat-plumbers-in-action/differential-shellcheck&patternType=literal) [![GitHub Repo stars](https://img.shields.io/github/stars/systemd/systemd?style=social)](https://github.com/systemd/systemd)



* [`cockpit-project/cockpit`](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/cockpit-project/cockpit%24+file:%5E%5C.github/workflows+redhat-plumbers-in-action/differential-shellcheck&patternType=literal) [![GitHub Repo stars](https://img.shields.io/github/stars/cockpit-project/cockpit?style=social)](https://github.com/cockpit-project/cockpit)



* [`89luca89/distrobox`](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/89luca89/distrobox%24+file:%5E%5C.github/workflows+redhat-plumbers-in-action/differential-shellcheck&patternType=literal) [![GitHub Repo stars](https://img.shields.io/github/stars/89luca89/distrobox?style=social)](https://github.com/89luca89/distrobox)



* [`flatpak/flatpak`](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/flatpak/flatpak%24+file:%5E%5C.github/workflows+redhat-plumbers-in-action/differential-shellcheck&patternType=literal) [![GitHub Repo stars](https://img.shields.io/github/stars/flatpak/flatpak?style=social)](https://github.com/flatpak/flatpak)



* more examples - [here](https://github.com/redhat-plumbers-in-action/differential-shellcheck/network/dependents?package_id=UGFja2FnZS0yOTkzNjMxNzI2)



## Configuration options



Action currently accepts following options:



```yml

# ...



- name: Differential ShellCheck

  uses: redhat-plumbers-in-action/differential-shellcheck@v5

  with:

    triggering-event: 

    base: 

    head: 

    pull-request-base: 

    pull-request-head: 

    push-event-base: 

    push-event-head: 

    diff-scan: 

    strict-check-on-push: 

    external-sources: 

    severity: 

    scan-directory: 

    exclude-path: 

    include-path: 

    token: 



# ...

```



### triggering-event



The name of the event that triggered the workflow run. Supported values are: `merge_group`, `pull_request`, `push` and `manual`.



* default value: `${{ github.event_name }}`

* requirements: `optional`



### base



`SHA1` of the commit which will be used as the base when performing differential ShellCheck. Input is used only when `triggering-event` is set to `manual`.



* default value: `undefined`

* requirements: `optional`



### head



`SHA1` of the commit which refers to the `HEAD` of changes. Input is used only when `triggering-event` is set to `manual`.



* default value: `undefined`

* requirements: `optional`



### merge-group-base



`SHA1` of the merge group's parent commit. Input is used when `triggering-event` is set to `merge_group`.



* default value: `${{ github.event.merge_group.base_sha }}`

* requirements: `optional`



### merge-group-head



`SHA1` of the merge group commit. Input is used when `triggering-event` is set to `merge_group`.



* default value: `${{ github.event.merge_group.head_sha }}`

* requirements: `optional`



### pull-request-base



`SHA1` of the top commit on the base branch. Input is used when `triggering-event` is set to `pull_request`.



* default value: `${{ github.event.pull_request.base.sha }}`

* requirements: `optional`



### pull-request-head



`SHA1` of the latest commit in Pull Request. Input is used when `triggering-event` is set to `pull_request`.



* default value: `${{ github.event.pull_request.head.sha }}`

* requirements: `optional`



### push-event-base



`SHA1` of the last commit before the push. Input is used when `triggering-event` is set to `push`.



* default value: `${{ github.event.before }}`

* requirements: `optional`



### push-event-head



`SHA1` of the last commit after push. Input is used when `triggering-event` is set to `push`.



* default value: `${{ github.event.after }}`

* requirements: `optional`



### diff-scan



Input allows requesting a specific type of scan. Input is considered only if `triggering-event` is set to `manual`.



Default types of scans based on `triggering-event` input:



| `triggering-event` | type of scan               |

|--------------------|----------------------------|

| `merge_group`      | differential               |

| `pull_request`     | differential               |

| `push`             | full                       |

| `manual`           | based on `diff-scan` input |



* default value: `true`

* requirements: `optional`



### strict-check-on-push



Differential ShellCheck performs full scans when running on a `push` event, but the Action fails only when new defects are added. This option allows overwriting this behavior. Hence when `strict-check-on-push` is set to `true` it will fail when any defect is discovered.



* default value: `false`

* requirements: `optional`



### external-sources



Enable following of source statements even when the file is not specified as input. By default, [ShellCheck](https://github.com/koalaman/shellcheck/blob/master/shellcheck.1.md) will only follow files specified on the command-line (plus `/dev/null`). This option allows following any file the script may source. This option may also be enabled using `external-sources=true` in `.shellcheckrc`.



* default value: `true`

* requirements: `optional`



### severity



Minimal severity level of detected errors that will be reported. Valid values in order of severity are `error`, `warning`, `info` and `style`.



* default value: `style`

* requirements: `optional`



### scan-directory



List of relative paths to directories that will be scanned for shell scripts. Globbing is supported. The list is a multi-line string, not a YAML list.



By default the whole repository is scanned. This feature is useful when you want to scan only a subset of the repository.



This feature is fully compatible with [exclude-path](#exclude-path) and [include-path](#include-path) options.



* requirements: `optional`

* example: `"build/**"`

* example for multiple values:



  ```yml

  scan-directory: |

    build/**

    testing

  ```



### exclude-path



List of relative paths excluded from ShellCheck scanning. Globbing is supported. The list is a multi-line string, not a YAML list.



* requirements: `optional`

* example: `"test/{bats,beakerlib}/**"`



### include-path



List of file paths that will be scanned by ShellCheck. Globbing is supported. The list is a multi-line string, not a YAML list.



* requirements: `optional`

* example: `"src/**.{shell,custom}"`



### display-engine



Tool used to display the defects and fixes in the console output. Currently supported tools are [`csgrep`](https://github.com/csutils/csdiff) and [`sarif-fmt`](https://github.com/psastras/sarif-rs/tree/main/sarif-fmt#readme).





  csgrep output example

  
`display-engine: csgrep`


  sarif-fmt output example

  
`display-engine: sarif-fmt`





* requirements: `optional`

* default value: `csgrep`



### token



The token is used to upload findings in SARIF format to GitHub.



* default value: `undefined`

* requirements: `optional`



The token needs to have the following [permissions](https://docs.github.com/en/rest/code-scanning#upload-an-analysis-as-sarif-data):



* `security_events: write` - required for **all repositories**.

* `actions: read` and `contents: read` - required only for **private repositories**.



> [!TIP]

>

> When the `token` isn't passed, the SARIF file won't be uploaded (the GitHub Security Dashboard won't be updated), but the Action will work as expected. SARIF file can also be uploaded manually using [sarif from outputs](#sarif) and [github/codeql-action/upload-sarif](https://docs.github.com/en/code-security/code-scanning/integrating-with-code-scanning/uploading-a-sarif-file-to-github#uploading-a-code-scanning-analysis-with-github-actions) GitHub Action.



## Outputs



Differential ShellCheck exposes following [outputs](https://docs.github.com/en/actions/using-jobs/defining-outputs-for-jobs).



### `sarif`



Relative path to the SARIF file containing detected defects. Example of how to use `sarif` output within the workflow:



```yaml

- id: ShellCheck

  name: Differential ShellCheck

  uses: redhat-plumbers-in-action/differential-shellcheck@v5



- if: always()

  name: Upload artifact with ShellCheck defects in SARIF format

  uses: actions/upload-artifact@v4

  with:

    name: Differential ShellCheck SARIF

    path: ${{ steps.ShellCheck.outputs.sarif }}



- if: always()

  name: Upload SARIF to GitHub using github/codeql-action/upload-sarif

  uses: github/codeql-action/upload-sarif@v2

  with:

    sarif_file: ${{ steps.ShellCheck.outputs.sarif }}

```



> [!TIP]

>

> `sarif` output can be used together with tools like [`microsoft/sarif-tools`](https://github.com/microsoft/sarif-tools?tab=readme-ov-file#sarif-tools) to convert SARIF to other formats like `codeclimate`, `csv`, `docx` and more. [Example of use](https://github.com/microsoft/sarif-tools?tab=readme-ov-file#suggested-usage-in-ci-pipelines).



### `html`



Relative path to the HTML file containing detected defects. Example of how to use `html` output within the workflow:



```yaml

- id: ShellCheck

  name: Differential ShellCheck

  uses: redhat-plumbers-in-action/differential-shellcheck@v5



- if: always()

  name: Upload artifact with ShellCheck defects in HTML format

  uses: actions/upload-artifact@v4

  with:

    name: Differential ShellCheck HTML

    path: ${{ steps.ShellCheck.outputs.html }}

```



[Example](docs/example.xhtml) of HTML output:





  HTML output example




## Using with Private repositories



Differential ShellCheck GitHub Action could be used in private repositories by any user. But code scanning-related features are available only for GitHub Enterprise users, as mentioned in [GitHub Documentation](https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/about-code-scanning):



_Code scanning is available for all public repositories on GitHub.com. Code scanning is also available for private repositories owned by organizations that use GitHub Enterprise Cloud and have a license for GitHub Advanced Security. For more information, see "[About GitHub Advanced Security](https://docs.github.com/en/get-started/learning-about-github/about-github-advanced-security)"._



## Using with Visual Studio Code



Differential ShellCheck doesn't have a Visual Studio Code plugin, but results can be accessed by using [SARIF Viewer](https://marketplace.visualstudio.com/items?itemName=MS-SarifVSCode.sarif-viewer) Visual Studio Code extension provided by Microsoft. Once installed, you have to connect your GitHub account with Visual Studio Code. Then, if you open a repository that uses Differential ShellCheck, you will see reported defects directly in your Visual Studio Code IDE.





  Visual Studio Code SARIF connect






  Visual Studio Code SARIF results




## Limitations



* `differential-shellcheck` Action doesn't run correctly when overwriting commits using `--force` and when the triggering event is `push`.



---



Useful documents: _[CHANGELOG](docs/CHANGELOG.md)_ | _[ARCHITECTURE](docs/ARCHITECTURE.md)_ | _[CONTRIBUTING](docs/CONTRIBUTING.md)_ | _[CODE_OF_CONDUCT](docs/CODE_OF_CONDUCT.md)_ | _[SECURITY](docs/SECURITY.md)_ | _[LICENSE](LICENSE)_