prettier --list-different lists only filenames without an actual error message, meaning there is nothing to match for message in a problem matcher.
It’d be great if GitHub Actions supported hard-coding a message instead of attempting to match one:
{
"problemMatcher": [
{
"owner": "prettier",
"message": "Code style issue (have you run prettier?)",
"pattern": [
{
"regexp": "^(.*)$",
"file": 1
}
]
}
]
}