Upgrading from 6.22/09 to 6.24/02


Just reading into the new ROOT version and pondering if Upgrading would be worth it. Maybe the experts have a better idea. I work with ROOT in quite a few programs and upgrades can cost me a lot if something doesn’t line up perfectly. My instincts are telling me to wait for a few more patches, a stable version that is a little older does just fine for my work.

Also, I don’t suppose there’s a straightforward way to do the upgrade if it came down to it?

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ROOT Version: 6.22/09
Platform: Ubuntu 21.04
Compiler: gcc 10.3.0

You can have MULTIPLE (different) ROOT versions installed SIMULTANEOUSLY in different directories (and easily switch between them). See e.g.:

As a rule of thumb, we always recommend to upgrade due to the bug fixes that come with each new release. You can also check the release notes for new features that might be interesting for you.

I agree with @Wile_E_Coyote 's suggestion to try it out before doing the jump. Another easy way to try out the new version is by installing it via conda in a dedicated environment, see https://root.cern/install . Or by running a Docker container, or by testing in on LXPLUS, etc.


Thank you. I’ll try that. I’m also seeing something about doing a ‘git pull’ command inside of the root_src folder in the reading? Can I get some clarification of what that is exactly?

@Jason_Forson, can you please provide a link or a quote of the part of the documentation that you are reading?

That’s for updating an old copy of the repository to the latest latest-stable branch. If you clone fresh, there is no updating to do. But actually, in general, you don’t have to build from source, using the pre-compiled binaries or a conda environment is much simpler and less prone to errors.

@jalopezg the quote is here: Building ROOT from source - ROOT

Not even that interesting @eguiraud
@jalopezg Installing ROOT - ROOT

# You may update your local copy by issuing a `git pull` command from within `root_src/`.
$ git clone --branch latest-stable https://github.com/root-project/root.git root_src
$ mkdir root_build root_install && cd root_build
$ cmake -DCMAKE_INSTALL_PREFIX=../root_install ../root_src # && check cmake configuration output for warnings or errors
$ cmake --build . -- install -j4 # if you have 4 cores available for compilation
$ source ../root_install/bin/thisroot.sh # or thisroot.{fish,csh}

@Jason_Forson Thanks for copying the quote! Actually, that only applies some time after cloning the repository (cloning a branch always retrieves the tip of that branch). That allows users to keep updated with upstream ROOT. Moreover, if you run $ git pull right after cloning, git will just tell you that there is nothing to do. Maybe we should make that point clear in the documentation?


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