GitHub Actions
GitHub Actions if expression starting with ! failed YAML parsing
`!` is reserved notation in YAML format.
GitHub Actions conditionals that begin with ! must use expression syntax or quoting because raw YAML treats ! as reserved notation.
Observed message
`!` is reserved notation in YAML format.
Why it happens
- An if condition starts with ! without using proper expression syntax.
- The workflow relies on YAML parsing a negation expression literally.
- A valid GitHub expression was written in a YAML-invalid form.
How to fix it
- Wrap the expression with ${{ }} when the condition starts with !.
- Quote or escape the expression if needed for the YAML context.
- Retest the workflow after changing the conditional syntax so the parser and expression evaluator both accept it.
