Warning about GITHUB_STEP_SUMMARY env var

I get this warning for each build execution. Is there anything I can do against that? From the linked documentation I learned that the file and env var GITHUB_STEP_SUMMARY should be set by Github, right?

We are using GitHub Enterprise Server 3.3.10. I can not share a link to the internal repositories. Version 1.39 of the action was used.

This is the log output of the step:

2022-07-19 06:39:08 +0000 - publish -  INFO - Reading build/test-results/**/*.xml (34 files, 2.1 MiB)
2022-07-19 06:39:08 +0000 - publish -  INFO - Available memory to read files: 5.9 GiB
2022-07-19 06:39:08 +0000 - publish -  INFO - Finished reading 34 files in 0.06 seconds
2022-07-19 06:39:08 +0000 - publish -  INFO - Publishing failure results for commit f5eaa3572aa120e90acae4c210741b[26](https://github.xxxx/xxx/xxx/runs/1843157?check_suite_focus=true#step:10:26)65c139ba
2022-07-19 06:39:10 +0000 - publish -  INFO - Created check https://github.xxxx/xxx/xxx/runs/1843185
2022-07-19 06:39:10 +0000 - publish - WARNING - Cannot append to environment file GITHUB_STEP_SUMMARY as it is not set. See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#environment-files
2022-07-19 06:39:10 +0000 - publish -  INFO - Created job summary
2022-07-19 06:39:14 +0000 - publish -  INFO - Edited comment for pull request #53: https://github.xxx.com/xxx/xxx/pull/53#issuecomment-1333[28](https://github.xxx.com/xxx/xxx/runs/1843157?check_suite_focus=true#step:10:28)
Warning: Cannot append to environment file GITHUB_STEP_SUMMARY as it is not set. See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#environment-files

The action is called like this:

    - name: Publish Test Results
      uses: EnricoMi/publish-unit-test-result-action@v1
      if: always()
      with:
        files: "build/test-results/**/*.xml"

It is executed on a Linux runner. I get the warning for regular commit (push) builds and for PRs.

[EnricoMi]

All features work, only the job summary won’t appear. Thanks for reporting!

[buehlerjochen]

Just to complete the information on this “issue”: We learned that just updating to GHActions Runner version 2.288.0 was not sufficient to use GITHUB_STEP_SUMMARY. It was also necessary to upgrade GH Enterprise to version 3.5+ because older versions do not set the variable.