ok op, tracey

thanks for all the help massaging this diff

Avoids clobbering open files for delta base/accumulation, leaking file descriptors, and triggering errors from close(2) during got_repo_close() as we try to close the same file descriptor more than once.

found by tracey

This prepares for callers of got_repo_open() that cannot afford to open files in /tmp, such as gotwebd. In a follow-up change, we could ask such callers to pass in the required amount of open temporary files. One consequence is that got_repo_open() now requires the "cpath" pledge promise. Add the "cpath" promise to affected callers and remove it once the repository has been opened. ok tracey

Saves us from doing a malloc/free call for every item on the list. ok op@

otherwise we call got_repo_close with repo being NULL and segfault there. ok stsp

Avoids overhead due to readdir calls while searching a pack index. ok op@

suggested by + ok naddy

Match command line arguments against references before matching object IDs. This makes it possible to use reference names that happen to match a short object ID. For example, a branch called "11ac" could not be diffed in OpenBSD src.git which happens to contain commit IDs that begin with hex digits 0x11ac. A bogus error would be reported in this situation: $ got diff master 11ac got: ambiguous object ID ok naddy

imsg_clear frees and closes resources allocated as part of enqueueing imsgs so it's a no-op after reads. discussed with and ok stsp@

tested by thomas, naddy, and myself

suggested by millert ok thomas_adam

suggested by millert ok thomas_adam

ok millert@

Potentially this function could return objects of a type that was not requested. Problem found by code inspection. This change does not affect any of our existing tests.