I tried to open my pre-existing repo in SourceTree (running macOS Catalina) and get the error "hg status failed with code 255....repository requires features unknown to this Mercurial: sparserevlog". My version of Mercurial (hg --version) is vdersion 5.3.
The repo works find and can be managed fine from the command line (for years). My hope was to transition away from the command line.
Well I managed to switch to the system version which was located at
mine is located at /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/mercurial
However....I now get error code 255 again but this time with "failed to import extension hgext.hgflow....module has no attribute."
Something of a can of worms it seems......