There's also a memory leak fixed. ok stsp@

The session process opened an object as part of a sanity check and simply closed it again. Opening an object involves decompression and combination of deltas. Add a new interface which checks whether an object ID exists without such overhead and call it from gotd.

We need to free the matched object id queue on each pack index iteration--not only when the objects/pack dir modification time has changed--otherwise the ids are leaked when we reinitialise the queue in got_packidx_match_id_str_prefix(). tweaked by + ok op@

This should prevent a use-after-free crash I observed in gotwebd. ok op@

Fix a regression in db82695e31945b3ce001a5fb69674c3638622368 where the fetch_all_branches configuration setting from got.conf was dropped and always defaulted to "no". Add corresponding regression test. ok stsp

Fixes a crash regression introduced when fetch/send were made to close the work tree earlier.

If the child has exited for some reason then we won't be able to send a stop message on the pipe. Ignore such errors while we are tearing a repository data structure down. The error should be harmless but can trip up gotwebd when cycling repositories out of its repo cache: gotwebd[29683]: gotweb_render_index: got-portable.git: unexpected end of file

and use it to avoid hardcoding the digest type in a few places. ok stsp@

it abstracts over the hash type and ensures that object ids are zero'ed before their sha1 digest is written. Needed by the incoming sha256 support. ok stsp@

It will soon grow functions to deal with sha256 too. stsp@ agrees.

In preparation for wide sha256 support; stsp@ agrees. Change done mechanically with find . -iname \*.[cy] -exec sam {} + X ,x/<sha1\.h>/i/\n#include <sha2.h>

reported by Lucas on IRC, who sent a patch which this commit was based on ok jamsek

Most extension allow only for a boolean value so the current behaviour of just sending the extension with a trueish value is fine. However, some extensions that we could eventually support (like "objectformat") have a string value. This is a preparatory step towards that. ok stsp@

got_repo_get_gitconfig_extensions is only used in gotadmin to check if the preciousObjects extension is active; let's replace it with a function that just checks whether a certain extension is active. It simplifies future changes to the extensions handling. ok stsp@