Authenticating to Subversion
The Subversion server does not require user authentication on every request. When you use Subversion integration in PyCharm, you only need to answer the authentication challenge of the server if it is required by the authentication and authorization policies. Upon successful authentication, your credentials are saved on disk, in ~/.subversion/auth/ on Unix systems or <USER HOME>/.subversion_IDEA on Windows and macOS.
When an authentication challenge comes from the server, the credentials are sought for in the disk cache; if the appropriate credentials are not found, or fail to authenticate, you are prompted to specify your login and password.
If necessary, you can opt to delete all credentials stored in the cache for the http, svn and ssh+svn protocols.