You could try a git status. A git pull will just add new modifications to your local working copy, but if you have modifications locally that do not conflict with incoming ones, your copy could still remain dirty.
git checkout . will overwrite your local changes with the master copy.
This is my shell script to update and build darktable:
#!/bin/bash
renice -n 19 -p $$
ionice -c 3 -p $$
rm -rf ~/.cache/darktable/cached_kernels*
cd ~/darktable ;
git clean -d -f -x ;
git submodule update
git pull --rebase
./build.sh --prefix /home/kofa/darktable-master && cmake --build "/home/kofa/darktable/build" --target install --
darktable sources are in /home/kofa/darktable, and I install to /home/kofa/darktable-master. git clean -d -f -x makes sure I start with a clean slate. I delete the compiled OpenCL kernels to make sure no old ones remain in my runtime environment: rm -rf ~/.cache/darktable/cached_kernels*.