Brian questioned the unnecessary alarms in v1 when "git diff" or "git index-pack" run in no-repository mode. I had the same feeling after sending v1. But instead of suppresing alarms, we could do better.
v2 breaks those "fall back to SHA-1" code into separate patches and handles it properly (I hope) instead of blind fall back like v1: - for index-pack, we can determine the needed algorithm from the pack file. I'm making an assumption here that pack files with new hash algo must step up file format version. But I think it's a reasonable assumption. - for diff --no-index, I still fall back to SHA-1 to generate the hashes like before. We could probably introduce a new command line option to use a different hash. But that work could be done later when an actual new hash has come Note, I didn't test but this series could potentially break 'pu' (in a good way). I initially was puzzled why the test suite didn't fail when the_repository->hash_algo was NULL (i.e. before Brian's fix). Then I found out that more work to abstract away SHA-1 hashing functions have been done since then. But because the_hash_algo is pre-initialized with SHA-1, these special cases did not show up until now. If there are more the_hash_algo conversion on 'pu', more "no-repo" cases could be spotted by the test suite. I think this makes pre-initializing the_hash_algo to NULL a very good point: during the abstraction work, we at least must identify the use cases like this (code running without repo). We don't have to fix it right away, but we can start thinking about how to deal with it. If we ignore it and switch to a new hash, these code will keep using SHA-1 and cause more headache in future. Nguyễn Thái Ngọc Duy (5): setup.c: initialize the_repository correctly in all cases sha1_file.c: keep a good name for "unknown" hash_algos[UNKNOWN] index-pack: check (and optionally set) hash algo based on input file diff.c: initialize hash algo when running in --no-index mode Revert "repository: pre-initialize hash algo pointer" builtin/index-pack.c | 26 +++++++++++++++++++++++++- builtin/init-db.c | 3 ++- cache.h | 3 ++- common-main.c | 10 ++++++++++ diff.c | 12 ++++++++++++ path.c | 2 +- repository.c | 2 +- setup.c | 5 ++++- sha1_file.c | 2 +- t/helper/test-dump-split-index.c | 2 ++ 10 files changed, 60 insertions(+), 7 deletions(-) -- 2.16.1.435.g8f24da2e1a
