FORCE_JAVASCRIPT_ACTIONS_TO_NODE20 has no effect

[EliahKagan]

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About ten days ago, on 7 March 2024, the GitHub changelog post GitHub Actions; All Actions will run on Node20 instead of Node16 by default documented the effect of setting the FORCE_JAVASCRIPT_ACTIONS_TO_NODE20 environment variable to true for a workflow:

If you would like to test this ahead of timer, you can choose to set FORCE_JAVASCRIPT_ACTIONS_TO_NODE20=true as an ‘env’ in their workflow or as an environment variable on your runner machine to force the use of Node20 now.

It seems to me that the way this uses "now" unambiguously expresses that setting this environment variable is currently effective at causing actions that specify Node 16 to be run on Node 20 instead, and can therefore already be relied on to check actions' compatibility with Node 20 and make decisions based on the results.

Searching public code and pull requests across GitHub for FORCE_JAVASCRIPT_ACTIONS_TO_NODE20 suggests that there are at least a few cases where this may have been assumed. I had assumed it myself, but I wanted to check to be sure, because it looks like this was implemented in actions/runner#3192, which was only merged a few days ago, on 14 March 2024, and there has not been any new release of actions/runner since then, the most recent release currently being v2.314.1 on 27 February 2024.

The version of Node being used is often not immediately clear in examining workflow results, even when debug logging is enabled (or perhaps I just don't know where to look for it). So I tested this by:

• Following the Create a JavaScript action tutorial, but using Node 16 instead of Node 20, and extending it to report process.version for the Node version, as well as process.env['FORCE_JAVASCRIPT_ACTIONS_TO_NODE20'] to ensure the environment variable was coming through. (The latter may not really be a sufficient check, since the environment variable is not documented to have an effect at the job or step level, but I also verified that I had placed it at the workflow level.) The Node version was still 16.
• Separately checking this in a workflow with the environment variable set as before but--instead of using a custom action for this purpose--using v6 the github-script action, passing a script that accesses process.version. This likewise reported Node 16.

When setting env for the workflows, I wrote the values as strings because environment variables' values are inherently strings rather than booleans. But I have also separately tested this with a variety of expressions of "true", including writing it as a boolean (even though it will still be converted to a string) and using "1". None affect the Node version.

As I suggested above, I think the reason is simply that the version of actions/runner that honors this variable has not yet been released (nor otherwise put into use on GitHub's own infrastructure). However, the post in the GitHub changelog blog does strongly seem to indicate this is in place now, so I wanted to check. If I'm making a mistake here and really this is working but I'm doing something wrong, then thank you for bearing with me. Otherwise, I think it might be worthwhile to make a correction to the blog post so that anyone who believes they have tested the effect of running their workflows with all JavaScript actions running on Node 20 can know to test again once the feature to do so is in place.