How to fix bup make AssertionError: assert not date.startswith(b’$Format’)


While trying to build bup using make you see the following error message:

set -e; bup_ver=$(./bup version); \
echo "s,%BUP_VERSION%,$bup_ver,g" > Documentation/substvars.tmp; \
echo "s,%BUP_DATE%,$bup_ver,g" >> Documentation/substvars.tmp
Traceback (most recent call last):
  File "/usr/lib/python3.10/", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib/python3.10/", line 86, in _run_code
    exec(code, run_globals)
  File "/home/uli/dev/deb-buildscripts/bup/lib/bup/", line 181, in <module>
    cmd_module = import_module('bup.cmd.'
  File "/usr/lib/python3.10/importlib/", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/home/uli/dev/deb-buildscripts/bup/lib/bup/cmd/", line 5, in <module>
    from bup import options, version
  File "/home/uli/dev/deb-buildscripts/bup/lib/bup/", line 20, in <module>
    assert not date.startswith(b'$Format')
make: *** [GNUmakefile:252: Documentation/substvars] Fehler 1


This error occurs because bup can’t determine the correct version & date for bup. This happens because you deleted the .git directory which bup needs in order to determine its version.

You can create a clone of bup with the .git directory intact by just cloning, for example, the specific version you want to build:

git clone -b 0.33 --depth 1

and then run

make -j4

as usual