Baked into the code was an assumption that a repository's git directory
could be determined by adding ".git" to its work tree (or nothing for bare
repos). That fails when core.worktree, or GIT_DIR and GIT_WORK_TREE are
used to separate the two.
This was attacked at the type level, by storing the gitdir and worktree
separately, so Nothing for the worktree means a bare repo.
A complication arose because we don't learn where a repository is bare
until its configuration is read. So another Location type handles
repositories that have not had their config read yet. I am not entirely
happy with this being a Location type, rather than representing them
entirely separate from the Git type. The new code is not worse than the
old, but better types could enforce more safety.
Added support for core.worktree. Overriding it with -c isn't supported
because it's not really clear what to do if a git repo's config is read, is
not bare, and is then overridden to bare. What is the right git directory
in this case? I will worry about this if/when someone has a use case for
overriding core.worktree with -c. (See Git.Config.updateLocation)
Also removed and renamed some functions like gitDir and workTree that
misused git's terminology.
One minor regression is known: git annex add in a bare repository does not
print a nice error message, but runs git ls-files in a way that fails
earlier with a less nice error message. This is because before --work-tree
was always passed to git commands, even in a bare repo, while now it's not.
annex.ssh-options, annex.rsync-options, annex.bup-split-options.
And adjust types to avoid the bugs that broke several config settings
recently. Now "annex." prefixing is enforced at the type level.
This is incomplete, it does not honor it yet for hash directories
and other annex bookkeeping files. Some of that is not needed for a bare
repo; some of it may be.
getConfig got a remote-specific config, and this confusing name caused it
to be used a couple of places that only were interested in global configs.
Rename to getRemoteConfig and make getConfig only get global configs.
There are no behavior changes here, but remote.<name>.annex-web-options
never actually worked (and per-remote web options is a very unlikely to be
useful case so I didn't make it work), so fix the documentation for it.
Add tuning, docs, etc.
Not sure if status is the right place to remote size.. perhaps unused
should report the size and also warn if it sees more keys than the bloom
filter allows?
Can't trust the key size to be accurate for tmp and bad keys, so check
actual file size. In the wild I saw the old code be wrong by a factor
of about 100!
If all tmp/bad keys are empty, they're not shown in status at all.
Showing 0 bytes and suggesting to clean it up seemed weird..
Stale and bad files are rare, so it's more efficient to use inAnnex to see
if they can be deleted, rather than keeping the list of all present keys
around for them.
Before, it leaked space due to caching lists of keys. Now all necessary
data about keys is calculated as they stream in.
The "nearly constant" is due to getKeysPresent, which builds up a lot
of [] thunks as it traverses .git/annex/objects/. Will deal with it later.
Much of the memory bloat turned out to be due to getKeysReferenced
containing a mapM, which is strict and buffered the whole list
rather than streaming it.
The other half of the bloat was due to building a temporary Set
in order to call S.difference. While that is more cpu efficient,
I switched to successive S.delete, since with it, I can run a whole
git annex unused in less than 8 mb of memory.
The whole Set of keys with content available is still stored in memory,
so running unused in a repo with a whole lot of file content will still
use more memory. In a repo containing 6000 files, it needed 40 mb.
Note that the status command still uses the bloatful getKeysReferenced.
This has two benefits.
1. When a lot of refs are going to be received, get them via lower cost
connection when possible.
2. Allows ctrl-c of sync after the cheaper remotes have been pulled from
(or pushed to).
Rather than go through the location log to see which files are present on
the remote, it simply looks at the disk contents directly.
I benchmarked this speeding up scanning 834 files, from an annex on my
phone's SSD, from 11.39 seconds to 1.31 seconds. (No files actually moved.)
Also benchmarked 8139 files, from an annex on spinning storage,
speeding up from 103.17 to 13.39 seconds.
Note that benchmarking with an encrypted annex on flash actually showed a
minor slowdown with this optimisation -- from 13.93 to 14.50 seconds. Seems
the overhead of doing the crypto needed to get the filenames to directly
check can be higher than the overhead of looking up data in the location
log. (Which says good things about how well the location log and git have
been optimised!) It *may* make sense to make encrypted local remotes not
have hasKeyCheap set; further benchmarking is called for.
Eventually, git-annex might try running this after making changes to
a remote. I have not yet thought of a good way for it to tell which
remotes it needs to run it on though. It can't just do it when
shutting down a cached ssh connection, because ssh connection caching
is optional, and that would not handle local remotes not accessed over ssh
either.
Now changes are staged into the branch's index, but not committed,
which avoids growing a large journal. And sync and merge always
explicitly commit, ensuring that even when they do nothing else,
they commit the staged changes.
Added a flag file to indicate that the branch's journal contains
uncommitted changes. (Could use git ls-files, but don't want to run
that every time.)
In the future, this ability to have uncommitted changes staged in the
journal might be used on remotes after a series of oneshot commands.
