This write permission frobbing is very appropriate in indirect mode,
since annexed objects are stored as immutably as can be managed. But not
in direct mode, where files should be able to be modified at any time.
There are already sufficient guards that there's no need to prevent a file
being written to while it's being ingested, in direct mode. The inode cache
will detect (most) types of modifications, and the add will fail. Then a
re-add should be done. The assistant should get another inotify change
event, and automatically add the new version of the file.
Fuzz tests have shown that git cat-file --batch sometimes stops running.
It's not yet known why (no error message; repo seems ok). But this is
something we can deal with in the CoProcess framework, since all 3 types of
long-running git processes should be restartable if they fail.
Note that, as implemented, only IO errors are caught. So an error thrown
by the reveiver, when it sees something that is not valid output from
git cat-file (etc) will not cause a restart. I don't want it to retry
if git commands change their output or are just outputting garbage.
This does mean that if the command did a partial output and crashed in the
middle, it would still not be restarted.
There is currently no guard against restarting a command repeatedly, if,
for example, it crashes repeatedly on startup.
The checkpresent hook can return either True or, False, or fail with a message
if it cannot successfully check the remote. Currently for glacier, when
--trust-glacier is not set, it always returns False. Crucially, in the case
when a file is in glacier, this is telling git-annex it's not there, so copy
re-uploads it. This is not desirable; it breaks using glacier-cli to retreive
that file later, and it wastes money/bandwidth.
What if it instead, when the glacier inventory is missing a
file, it returns False. And when the glacier inventory has a file, unless
--trust-glacier is set, it *fails*.
The result would be:
* `git annex copy --to glacier` would only send things not listed in inventory. If a file is listed in the inventory, `copy`
would complain that --trust-glacier` is not set, and not re-upload the file.
* `git annex drop` would only trust that glacier has a file when --trust-glacier is set. Behavior unchanged.
* `git annex move --to glacier`, when the file is not listed in inventory, would send the file, and delete it locally. Behavior unchanged.
* `git annex move --to glacier`, when the file is listed in inventory, would only trust that glacier has the file when --trust-glacier is set
* `git annex copy --from glacier` / `git annex get`, when the file is located in glacier, would trust the location log, and attempt to get the file from glacier.
Ie, when there'a a conflicted merge we may get foo.variant-xxxx
created in a merge. If a second merge conflict occurs on that new file,
it was not falling back to putting in the whole key (which should stop
the merge conflicts happening for good, but is ugly).
The current manual mode preferred content expression is:
"present and (((exclude=*/archive/* and exclude=archive/*) or (not (copies=archive:1 or copies=smallarchive:1))) or (not copies=semitrusted+:1))"
The old matcher misparsed this, to basically:
OR (present and (...)) (not copies=semitrusted+:1))
The paren handling and indeed the whole conversion from tokens to the
matcher was just wrong. The new way may not be the cleverest, but I think
it is correct, and you can see how it pattern matches structurally against
the expressions when parsing them.
That expression is now parsed to:
MAnd (MOp <function>)
(MOr (MOr (MAnd (MOp <function>) (MOp <function>)) (MNot (MOr (MOp <function>) (MOp <function>))))
(MNot (MOp <function>)))
Which appears correct, and behaves correct in testing.
Also threw in a simplifier, so the final generated Matcher has less
unnecessary clutter in it. Mostly so that I could more easily read &
confirm them.
Also, added a simple test of the Matcher to the test suite.
There is a small chance of badly formed preferred content expressions
behaving differently than before due to this rewrite.
I noticed that when my modem hung up and redialed, my xmpp client was left
sending messages into the void. This will also handle any idle
disconnection issues.
This bug was turned up by the test suite, running fsck in direct mode.
A repository was cloned, was put into direct mode, was fscked, and fsck
incorrectly said that no copy existed of a file, that was actually present
in origin.
This turned out to occur because fsck first did a Annex.Branch.change,
recording that it did not locally have the file. That was recorded in the
journal. Since neither the git annex direct not the fsck had yet needed to
read any info from the branch, but had only made changes to it, the
origin/git-annex branch was not yet merged in. So the journal got a
location log entry written to it, but this did not include
the location log info for the origin. When fsck then did a
Annex.Branch.get, it trusted the journal was cosnsitent, and returned it,
again w/o merging from origin/git-annex. This latter behavior is the
actual bug.
Refer to commit e9bfa8eaed for the thinking
behind it being ok to make a change to a file on the branch, without
first merging the branch. That thinking still stands. However, it means
that files in the journal cannot be trusted to be consistent if the branch
has not been merged. So, to fix, just enure the branch gets merged, even
when reading from the journal.
In tests, this does not seem to cause any extra merging. Except, of course,
in the one case described above. But git annex add, etc, are able to make
changes w/o first merging the branch.
The bug was in movein, which just replaceFile'd the file with a symlink,
even if it already had the desired content, before trying to pull the
content out of the annex and replace the symlink with it.
That was ok-ish for non conflicted merges, where if the file existed it would
be an old version of the content. But for conflicted merges, the automatic
merge resolver has already run, and will have already put the desired
content into the file for the local variant.
Also, made removeDirect not trust that the associated files map is correct.
Only if it can verify that another file has the content will it not move it
into .git/annex/objects.
As seen in this bug report, the lifted exception handling using the StateT
monad throws away state changes when an action throws an exception.
http://git-annex.branchable.com/bugs/git_annex_fork_bombs_on_gpg_file/
.. Which can result in cached values being redundantly calculated, or other
possibly worse bugs when the annex state gets out of sync with reality.
This switches from a StateT AnnexState to a ReaderT (MVar AnnexState).
All changes to the state go via the MVar. So when an Annex action is
running inside an exception handler, and it makes some changes, they
immediately go into affect in the MVar. If it then throws an exception
(or even crashes its thread!), the state changes are still in effect.
The MonadCatchIO-transformers change is actually only incidental.
I could have kept on using lifted-base for the exception handling.
However, I'd have needed to write a new instance of MonadBaseControl
for the new monad.. and I didn't write the old instance.. I begged Bas
and he kindly sent it to me. Happily, MonadCatchIO-transformers is
able to derive a MonadCatchIO instance for my monad.
This is a deep level change. It passes the test suite! What could it break?
Well.. The most likely breakage would be to code that runs an Annex action
in an exception handler, and *wants* state changes to be thrown away.
Perhaps the state changes leaves the state inconsistent, or wrong. Since
there are relatively few places in git-annex that catch exceptions in the
Annex monad, and the AnnexState is generally just used to cache calculated
data, this is unlikely to be a problem.
Oh yeah, this change also makes Assistant.Types.ThreadedMonad a bit
redundant. It's now entirely possible to run concurrent Annex actions in
different threads, all sharing access to the same state! The ThreadedMonad
just adds some extra work on top of that, with its own MVar, and avoids
such actions possibly stepping on one-another's toes. I have not gotten
rid of it, but might try that later. Being able to run concurrent Annex
actions would simplify parts of the Assistant code.
