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.

Feature requested by naddy. ok naddy, who also suggested some tweaks that will arrive shortly

ok millert