The self-upgrade feature is undesirable when deno is installed from
(Linux) distribution repository - using a system package manager. This
change will allow package maintainers to build deno with the "upgrade"
subcommand and background check disabled.
When the user runs `deno upgrade <args>` and the upgrade feature is
disabled, it will exit with error message explaining that this deno
binary was built without the upgrade feature.
Note: This patch is already used in the Alpine Linux’s
[deno](https://pkgs.alpinelinux.org/packages?name=deno) package.
This commit adds `--unstable-hmr` flag, that enabled Hot Module Replacement.
This flag works like `--watch` and accepts the same arguments. If
HMR is not possible the process will be restarted instead.
Currently HMR is only supported in `deno run` subcommand.
Upon HMR a `CustomEvent("hmr")` will be dispatched that contains
information which file was changed in its `details` property.
---------
Co-authored-by: Valentin Anger <syrupthinker@gryphno.de>
Co-authored-by: David Sherret <dsherret@gmail.com>
