On Mon, Jun 8, 2020 at 10:18 AM Junio C Hamano <gitster@xxxxxxxxx> wrote: > > It may make sense to do one of the two things: > > - The lighter weight one is to rename the macro to the reflect the > trait we are trying to capture more faithfully: "fopen opens > directories" and leave the code and performance characteristics > as-is. > > - Heavier weight one is to audit callers of fopen() and only let > those that know they do not have a directory directly call > fopen(). The other callers would call our wrapper under a > different name. This way, the former won't have to pay the > overhead of checking for "you gave me a directory but I only take > a file" error twice. This is what Brandon proposed in the > thread. > > Doing neither would leave this seed of confusion for later readers, > which is not ideal. I am tempted to say that we for now should do > an even lighter variant of the former, which is to give a comment. > > Thoughts? I'd suggest a medium weight approach which would be to introduce a new function with an appropriate name (fopen_file_only()?) that behaves the way we want it to, and replace every existing fopen() call with this new function. We could introduce a new macro, which I think would only be used on Windows, to say "fopen already fails to open directories" (FOPEN_FAILS_ON_DIRECTORIES?) so that fopen_file_only could be simplified to just a bare fopen there. That way it's clear to the reader, at the callsite, that the call does not have the standard behavior of fopen. Then, FREAD_READS_DIRECTORIES could be removed from all but the 1 or 2 platforms that it was originally set for. I'd imagine that we'd basically just promote the git_fopen() function from compat to become the implementation of the first tier fopen_file_only() function. On the FREAD_READS_DIRECTORIES platforms, a bare fopen would also become fopen_file_only(). The call to fopen() within fopen_file_only() would obviously need to take this into account to ensure that it calls the real fopen(). I think this would put the pieces in place for someone to audit all of the existing uses of fopen_file_only() and potentially replace them with a straight fopen() if appropriate. And it would allow future code to explicitly make the choice between fopen_file_only() or just fopen(). None of this would produce any functional change on any of our platforms, but I think it would make things more clear. -Brandon
