Avoid an installation if the requested ruby is already installed

[ferrarimarco]

Currently I am running ruby-install ruby x.x.x to install Ruby as a non privileged user.

If I run the same command again with the same user, ruby-install does not check if the package is already installed, but installs it one more time, leading to a waste of time.

[postmodern]

There is a --no-reinstall flag, or do you want --no-reinstall to be the default behavior?

[havenwood]

@ferrarimarco Sometimes folk build the same version once again but differently.

[ferrarimarco]

@postmodern I didn't notice the flag. Is there any documentation? Maybe it could be useful to have a --force-reinstall flag and the --no-reinstall be the default, like other package managers do, like pip for example.

@havenwood I think it's a bad practice so it should not be encouraged.

[havenwood]

@ferrarimarco What's bad practice about rebuilding the same version with different build options? Say for example you want to rebuild 2.3.0 with tail call optimization or whatever else?

[ferrarimarco]

@havenwood I misunderstood your first answer. This is a perfectly fine use case.

[todd-a-jacobs]

I came to this thread because I was surprised to find that ruby-install --update ruby will (by default) reinstall the current version even if it's already the latest version. I'm also currently looking through the code to see if YJIT is currently enabled by default for later versions. It's also a little unclear whether build options passed are preserved if the -c flag is passed to ruby-install as that cleans up the build directory.

I wrote a Fish function this morning that checks the current Ruby version against the latest stable builds as reported by ruby-install, and then calls ruby-install with some hard-coded defaults and updates ~/.ruby-version with the latest C Ruby. This is probably not what everyone wants, so I'm not proposing it as a solution. I'm just suggesting that a recompilation of an existing Ruby by default is not what most people intend when they "upgrade."

Even if nothing else changes, I think "--reinstall" or "--recompile" should be non-default options, while "--no-reinstall" should be the default behavior. Especially when upgrading libraries, a deliberate recompile can make sense, but reinstalling from scratch by default wastes CPU cycles that likely aren't intended. Just my $0.02 regarding my own personal experience; other use cases may vary.

[todd-a-jacobs]

There is a --no-reinstall flag, or do you want --no-reinstall to be the default behavior?

If it’s an option, I think not reinstalling should be the default behavior. A reinstall or rebuild flag could enable recompiling when someone really wants to make changes such as rebuilding with YJIT enabled/disabled. I doubt rebuilding is what most people intend as the default use case when running a bare install, though, unless Ruby-install is caching build options and detects a change.

[postmodern]

Should --no-reinstall be the default behavior (i.e. not installing the same ruby into the same location twice)?