Several MSAN issues in local pytests and CI pipeline

Basic info

• Fixed point:
  • Encoder (fixed): 3342b22c
  • Decoder (fixed): 3342b22c

Bug description

When running the pytests locally using the basop-ci-branch and a clang 18 MSAN build in the WSL (e.g. via prepare_pytests.py), almost all the tests fail with a use-of-uninitialized-value MSAN Warning. These issues originate from various locations throughout the encoder and decoder libraries. For some reason, this is not a problem in the CI pipeline, which runs the MSAN tests successfully.

Furthermore, the last ivas-pytest-msan test has failed with the following error

bash: line 287: CI_MERGE_REQUEST_TARGET_BRANCH_NAME: unbound variable

These issues need to be investigated and fixed, if necessary.

Ways to reproduce

python3 tests/prepare_pytests.py

or

pytest "specific test to execute"