Feature request: implement dry-run mode

Hint: maybe enable github Discussions, so folks can ask questions without filing them as issues?

Interested in this, but trying to figure out if it fits in a particular project's workflow. It's hard to tell, if you create a stack of PRs, if the maintainer can merge individual ones as s/he finishes with them through the web UI "as I've always done", or if it has to be done all in one go from the cli (presumably by the submitter, since others are unlikely to have the branches locally in the right form). There's a hint at the latter in the workflow description with this line:

instead of merging them you should use land.

It's also not entirely clear how the workflow works once submit happens and reviewers start asking for changes:

If we need to make changes to any of the PRs (e.g. to address the reviewfeedback), we simply amend the desired changes to the appropriate git commits and run submit again.

That implies force-pushing, which is generally considered a no-no.

If needed, we can rearrange commits or add new ones.

Does that imply new PRs will be created too? Or will they be included in existing branches/PRs?

To come down to something resembling a suggestion/feature request - while some of us aren't really sure what's going on under the covers and whether it will be okay for our particular needs, could the project implement a dry-run mode that shows what would be done without actually making the live changes?

Start by reading the workflow description around submit and land, then trace the entry points for those commands. Define the dry-run output for each live change and verify that the mode performs no GitHub or branch mutations.