On Tue, Mar 29, 2022 at 11:04:18AM +0200, Ævar Arnfjörð Bjarmason wrote: > > On Wed, Mar 23 2022, Taylor Blau wrote: > > > On Wed, Mar 23, 2022 at 03:22:13PM -0400, Derrick Stolee wrote: > >> On 3/23/2022 2:03 PM, Josh Steadmon wrote: > >> > prepare_repo_settings() initializes a `struct repository` with various > >> > default config options and settings read from a repository-local config > >> > file. In 44c7e62 (2021-12-06, repo-settings:prepare_repo_settings only > >> > in git repos), prepare_repo_settings was changed to issue a BUG() if it > >> > is called by a process whose CWD is not a Git repository. This approach > >> > was suggested in [1]. > >> > > >> > This breaks fuzz-commit-graph, which attempts to parse arbitrary > >> > fuzzing-engine-provided bytes as a commit graph file. > >> > commit-graph.c:parse_commit_graph() calls prepare_repo_settings(), but > >> > since we run the fuzz tests without a valid repository, we are hitting > >> > the BUG() from 44c7e62 for every test case. > >> > > >> > Fix this by refactoring prepare_repo_settings() such that it sets > >> > default options unconditionally; if its process is in a Git repository, > >> > it will also load settings from the local config. This eliminates the > >> > need for a BUG() when not in a repository. > >> > >> I think you have the right idea and this can work. > > > > Hmmm. To me this feels like bending over backwards in > > `prepare_repo_settings()` to accommodate one particular caller. I'm not > > necessarily opposed to it, but it does feel strange to make > > `prepare_repo_settings()` a noop here, since I would expect that any > > callers who do want to call `prepare_repo_settings()` are likely > > convinced that they are inside of a repository, and it probably should > > be a BUG() if they aren't. > > I think adding that BUG() was overzelous in the first place, per > https://lore.kernel.org/git/211207.86r1apow9f.gmgdl@xxxxxxxxxxxxxxxxxxx/; I think Junio raised a good point in https://lore.kernel.org/git/xmqqcznh8913.fsf@gitster.g/ , though some of the detail was lost in 44c7e62e51 (repo-settings: prepare_repo_settings only in git repos, 2021-12-06). > I have that in my local integration branch, because I ended up wanting > to add prepare_repo_settings() to usage.c, which may or may not run > inside a repo (and maybe we'll have that config, maybe not). I see what you're saying, though I think we would be equally OK to have a default value of the repo_settings struct that we could rely on. I said some of this back in https://lore.kernel.org/git/Yjt6mLIfw0V3aVTO@nand.local/ , namely the parts around "I would expect that any callers who do want to call `prepare_repo_settings()` are likely convinced that they are inside of a repository, and it probably should be a BUG() if they aren't." Thinking in terms of your message, though, I think the distinction (from my perspective, at least) is between (a) using something called _repo_-settings in a non-repo context, and (b) calling a function which is supposed to fill in its values from a repository (which the caller implicitly expects to exist). Neither feel _good_ to me, but (b) feels worse, since it is making it OK to operate in a likely-unexpected context with respect to the caller's expectations. Anyway, I think that we are pretty far into the weeds, and it's likely time to turn around. I don't have that strong a feeling either way, and in all honesty either approach is probably just fine. Thanks, Taylor
