I had no issues yesterday but today I cannot run git svn anymore. It says:
git: 'svn' is not a git command. See 'git --help'.
The most similar commands are
fsck
mv
show
I don't know if it's relevant but since yesterday I updated npm(6.14.4) and node (v12.6.0).
I'm on macOs Catalina
UPDATE: SEPTEMBER 2020
It seems the end is here. Following the original suggestion will delete subversion forever. I found a verified version of Subversion for MacOS and downloaded and installed it. I then needed to add Subversion to the $PATH variable to supersede Apple's svn (which just prints a message saying subversion is no longer included). To add it, add this line to your ~/.zprofile:
export PATH=/opt/subversion/bin:$PATH
This will fix svn. I still have not figured out how to fix git svn.
NB: I also am aware that one can get subversion from homebrew, but homebrew is prohibited by my company's policies. If homebrew works better for somebody, please post your results here.
ORIGINAL ANSWER: MARCH 2020
Same thing happened to me today. After software update, git svn and svn are gone. It seems that Apple is deprecating Subversion in XCode:
Command line tool support for Subversion — including svn, git-svn, and related commands — is no longer provided by Xcode. If you need Subversion or related command line tools, install the Command Line Tools package by running xcode-select --install. (50266910)
In the mean time, I was able to resolve this situation by deleting the XCode command line tools and reinstalling them:
sudo rm -Rf /Library/Developer/CommandLineTools
sudo xcode-select --install
After that, git svn and svn were back. Hopefully that will give us a stay of execution before final deprecation and deletion.